CA2523882A1

CA2523882A1 - Work piece with a layer of hard material that contains alcr and a method for producing this

Info

Publication number: CA2523882A1
Application number: CA002523882A
Authority: CA
Inventors: Volker Derflinger; Andreas Reiter; Christoph Gey
Original assignee: Individual
Current assignee: Oerlikon Surface Solutions AG Pfaeffikon
Priority date: 2003-04-28
Filing date: 2004-03-24
Publication date: 2004-07-15
Anticipated expiration: 2024-03-24
Also published as: MXPA05011608A; JP6383333B2; TWI354708B; IL171467A; EP2275585A1; CA2523882C; JP2010275639A; JP2011126009A; WO2004059030A3; KR20060005397A; EP1627094A2; WO2004059030A2; JP2015214021A; KR101047630B1; SI1627094T1; BRPI0409913A; EP1627094B1; BRPI0409913B1; TW200500483A; JP2014076540A

Abstract

Disclosed is a work piece with a layer system that contains at least one layer of composition (Al y Cr1-y) N, with a cubic structure, where 0.415 <=y <=0.695, the composition of the layer changing over the thickness of the layer continuously or incrementally, the work piece being a milling tool, a broaching cutter, a reamer, a turnover cutting plate for turning and milling, a molding tool, an injection-molding tool, a forming tool or a hot-forming tool. Also disclosed is a method for producing such a work piece or part.

Description

Work Piece with a Layer of Hard Material that Contains AICr and a Method for Producing This The technical domain to which the present invention relates includes work pieces that are covered with a layer system that contains at least one (AlyCr~ _y) X layer that is composed as in Claim 1 and Claim 2. The present invention also relates to a PVD process for depositing an (AlyCr~_y) X layer on a work piece as in Claim 16.
In particular, the present invention includes:
- work pieces that are coated with hard material and have one or a sequence of a number of different aluminum chromium nitride or aluminum carbon nitride layers;
- tools, in particular cutting and forming tools (drills, milling tools, turnover cutting plates, thread cutters, thread formers, hob milling cutters, stamps, matrices, drawing tools, etc.), and the use of these tools with AICrN or AICrCN layers;
- components, in particular components from the machine-building domain, such as gear wheels, pumps, barrel tappets, piston rings, injector needles, complete bearing sets or individual parts thereof, and the use of these component parts with AICrN or AICrCN layers;
- a method for producing AICrN or AICrCN layers with a defined layer structure.
Different AICrN layers are known from the prior art. JP 09-041127 describes a wear-resistant layer of hard material of the following composition (Al, _yXy) Z, wherein X =
Cr, V or Mg, Z = N, C, B, CN, BN or CBN and 0 < Y < 0.3. This layer has been used advantageously to increase the useful life of turnover cutting plates.
In their paper "Multicomponent hard thin films . . ., " Thin films (Proc. 4t'' Int. Sympos.
Trends and New Applications of Thin Films 1993) DGM Info.gesellschaft Oberursel.
1993.) p. 73, D. Schulz and R. Wilberg describe a CrAIN layer that, during a drilling test, doubled the service life of a drill that was coated with TiAIN. The layer was precipitated by a hollow cathode process that, however, caused a pronounced variation of the chromium/aluminum distribution in the (CrAI)N layer because of an intermittent vapourization process.
In their paper titled "Oxidation Resistance of Cr ~_XAIX N and Ti~_XAIXN
Films," Surf. &
Coat Tech., Vol. 165, 2, (2003), pp. 163-167, M. Kuwate et al. describe a Cr, _XA12N layer that, with a high aluminum content and wurzite structure, displayed improved resistance to oxidation as compared to conventional TiAIN layers.
In their paper titled "Investigations of Mechanical and Tribol Properties of CrAIN + C
Thin Coatings Deposited on Cutting Tools," E. Lugschneider, K. Bobzin, and K.
Lackner compare arced CrAIN layers and CrAIN layers that additionally have an even harder covering layer that contains carbon. All the layers display a coefficient of friction that rise rapidly to higher values.
It is the objective of the present invention to describe work pieces coated with (AlyCr~_y) X, for example, machining tools, cutting and forming tools, or components for machine building and die making, as well as a method for depositing such layers on a work piece, and at the same time avoid the disadvantages found in the prior art.
This includes work pieces, for example, that are of an adjustable, even or variable layer composition, at least with reference to the Al/Cr ratio, and which display greater wear resistance, at least in specific applications, than work pieces that have previously known layers.
In order to investigate the wear resistance of (AIYCrI_y) N or -CN layers on different tools, Cr layers with various aluminum contents were deposited on different work pieces in Type RCS industrial machinery (Balzer company), as described in EP 1186681 in Figure 3-6, Description page 12, lines 26 to page 14, line 9. This publication is hereby declared to be an integral part of this application. To this end, the cleaned work pieces were secured, depending on their diameters, on two- or, in the case of diameters smaller than 50 mm, on threefold rotating substratum Garners, and two titanium targets and four targets produced by powdered metallurgy which were of different AICr alloys were built into six cathodic arc sources attached to the walls of the coating machinery.
Next, the work pieces were initially brought to a temperature of approximately 500°C by irradiation heaters similarly installed in the machinery, and the surface was subj ected to etching cleaning by applying a bias voltage of -100 to-200 V in an Ar atmosphere at a pressure of 0.2 Pa.
Subsequently, by operating the two Ti sources with a power of 3.5 kW (140 A) in a pure nitrogen atmosphere at a pressure of 3 Pa and a substrate voltage of -50 V for a period of five minutes, a TiN adhesive layer, approximately 0.2~m thick, and an AICrN
layer was next deposited by operating the four AICr sources with a power of 3 kW for a period of 120 minutes. In order to achieve an optimum layer transition, the sources were operated jointly for a period of two minutes. Then a nitride layer on an AICr base was deposited in a pure nitrogen atmosphere, also at a pressure of 3 Pa and a substrate voltage of -50 V.
In principle, the process pressure in each of these steps can be set in a range of 0.5 to approximately 8 Pa, preferably between 2.5 and S Pa, and either a pure nitrogen atmosphere or a mixture of nitrogen and a noble gas such as argon can be used for a nitride layers, or a mixture of nitrogen and a gas that contains carbon which can, if necessary, have a noble gas added to it, can be used for carbon nitride layers.
Accordingly, in order to deposit layers that contain oxygen or boron, oxygen or a gas that contains boron can be added, as known.
Layer properties such as the crystal structure of the layer, and layer thickness, layer hardness, wear resistance, and the adhesion of AICrN layers as a function of the chemical composition and crystal structure, as well as the composition of the targets that were used, are set out in Table 1. Process parameters such as target power, substrate bias voltage, and process pressure and temperature, are set out in Table 2.
Table 3 shows a measurement series in which the AICr layers were deposited using targets with an Al/Cr ratio of 3, during the application of various substrate voltages.
When this is done, the wear resistance as determined with a precision wear tester manufactured by Fraunhoferinstituts-IST Brunswick, when a calotte-grinding method that had been modified from DIN EN 1071-2 was used in order to determine the rate of wear. The details of this method can be found in Michler, Surf. & Coat. Tech., Vol. 163-164 (2003), p. 547, Col. l, and Figure 1. This publication is hereby declared to be an integral part of this application.
The present invention will be described in greater detail below on the basis of the drawings appended hereto. These drawings show the following:
Figure 1: XRD spectrum of an AICrN with B1 and B4 structure;
Figure 2: XRD spectrum of an AICrN as a function of the chemical composition Al/Cr:
A = 75/25, C = 50/50, D = 25/75.
As can be seen from Table 1 and Figure l, and as is known from Kawate, "Micro-hardness and lattice parameter of Cry-XAIX N," J. Vac. Sci. Technol. A 20 (2), Mar/Apr 2002, pp. 569-571, an hexagonal (B1) layer structure could be established for Al proportions of > 70 AT% of metal content in the layer, and a cubic (B1) lattice structure could be established for smaller A1 proportions. For hexagonal layers, HV
values of approximately 2100 HVo.os could be measured, although for cubic layer structures higher HV values of approximately 2800-3100 HVo.os could be measured (see Table 1).
At higher Cr contents (Sample D), a hardness of approximately 2300 HVo,os was established.
At this composition, as distinct from the A1N lattice with a high aluminum content, as is shown in Figure 2A, there is a CrN lattice as in Figure 2D.
Next, the service life of 6 mm HSS drills coated with AICrN was determined on DIN
1.2080 steel material with a hardness of 230 HS at a feed of 0.12 mm and a cutting speed of 35 m/min as in Example 1 below. When this was done, it was revealed that, in contrast to the range of (AlyCrl_y) N <Y <_ 0.7 that was described as being particularly favorable in JP 09-041127, a chromium content of greater than 0.3 was advantageous.
At chromium contents of greater than or equal to 0.8, the productivity fell once again for this range of application because of the existing CrN lattice. In this case, the increase in service life of cubic as compared to hexagonal AICrN layers amounted to 235%.
For layers in a transition range with an aluminum content between 60% and 75 at%, it is possible to adjust not only the preferred orientation, but also the underlying structure of the crystal lattice, by way of the process parameters. Thus, for example, in Test B (Table 2) at a low pressure of 1 Pa and a substrate voltage of -50 V, an hexagonal structure is generated, whereas in a pressure range from 3 Pa and the substrate voltage of -50 V, a cubic structure is generated. The hexagonal structure is thus deposited at a relatively lower bias voltage and low pressure, whereas the preferred cubic structure is deposited at higher pressure or at the amount according to a higher bias voltage. It is no longer possible to generate a cubic layer structure at higher aluminum contents.
Work pieces according to the present invention are thus distinguished by a cubic (AlyCr~_y) X coating of the following composition: X = N or CN, but preferably N, and 0.2 < Y < 0.7, preferably 0.40 < y <_ 0.68. The layer structure is microcrystalline with a median grain size of approximately 20-120 nm.
The methods according to the present invention are distinguished by a sequence of operations in which a cubic (AlyCra_y) X layer of a composition as defined above is deposited. Target compositions of 75 to 15% aluminum content can be used advantageously for the cathodic arc method described above. At high aluminum contents, process parameters are to be set as described above in order to generate a cubic crystal structure.
When this is done, it is advantageous to use targets produced by powder metallurgy, in particular by cold pressing; these targets display greater strength than Al/Cr targets produced by fusion or sintering, which mostly contain brittle phases, particularly at high aluminum contents.

Such targets are cold pressed by mixing the powdered starting materials and then compacted by repeated forming, for example in a forging press, at temperatures below 660 °C during flow and low-temperature welding, and brought to an end state with a theoretical density of approximately 96-100%.
In addition, it could also be established that with an AICrN coating that was deposited, for example, using targets of a composition AI/Cr = 3, wear resistance could be influenced by the substrate bias voltage. As the substrate bias voltage rises, resistance to abrasive wear declines (see Table 3). Even at a very small-substrate voltage, which is not shown explicitly in the table, of only a few volts (3-10 V and any intervening values), it is possible to achieve a clear improvement as compared to floating substrates (no external voltage supply). At approximately -20 V, wear resistance for AICr = 3 reaches a maximum and falls once again at higher voltages. An optimal range of substrate voltage between 3 to 150 V, in particular between 5 and 40 V, can be derived from the test to determine wear behavior; a very low rate of wear between 0.4 and 1.0, in particular between 0.4 and 0.8 m3m-1N-~ 10-15 can be derived, was measured in these. The same applies for layers according to the present invention, which is to say, cubic layers with different Al/Cr composition at which no wear rates above 1.5 m3rri ZN-110-15 were measured. Tt should be noted however, that the wear resistance of floating layers deposited at a higher substrate voltage is significantly greater than the wear resistance of known TiAIN layers, the wear coefficient of which is significantly greater.
For example, a wear rate of 3.47 m3rri 1N-110-15 was measured for a TiAIN layer deposited analogously to the AICrN layers (Experiment 2, Al 47 at%, Ti 53 at%).
Using TiAI targets produced by the method described above, in particular by powder metallurgy, it is possible to deposit layers having a low level of roughness.
The measured Ra values lie in the range between 0.1 and 0.2 ~m and are thus in the same range as comparably produced CrN layers. Further smoothing of the layers will result from the use of a magnetic field generator that includes two magnetic systems of opposing polarity and which is so configured that the B1 component of the resulting magnetic field that is perpendicular to the surface displays essentially constantly small values across the major part of the service, or is zero. At the same time, the value of the perpendicular B~ component is less than 30 and preferably less than 20, and in particular is less than 10 Gauss. The Ra value of the (AlyCr~_y) X layers that are deposited thereby lie in the range from 0.05 to 0.15 pm. The magnetic field was generated by two coils of opposing polarity arranged coaxially behind the target.
In addition, during the precipitation of (AlyCr~_y) X layers, other preferably highly conductive nitride or metallic adhesive layers can be used, or the use of such an adhesive layer can be dispensed with for certain applications. For example, in order to achieve particularly high productivity, an AICr-/AICrN- adhesive layer can be applied in place of a TiN adhesive layer, which makes it possible to provide all the arc sources of a coating machinery with AICr targets and increase the coating rates.
In the same way, it is also possible to deposit gradient layers with, for example, aluminum contents that increase towards the surface, if two target types with a different Al/Cr ratio are used or if, proceeding from a Cr and/or CrN adhesive layer, a change in the layer composition is achieved by, for example, continuous or incremental regulation of the corresponding target powers of a coating chamber that is equipped with Cr as well as AICr targets. What is important for an industrial application of such a coating system is the possibility of setting up the process parameters so that they can be replicated essentially across the whole coating sequence, and thus across the whole thickness of the layer. Minimal variations in the composition, like those brought about by substrate movement, for example, on a single or multiple rotating substrate carrier, can be used additionally for nanostructuring that is formed partially or across the whole thickness of the layer, i.e., lamination in the nanometer or micrometer range. If unalloyed chromium and aluminum targets are used, a more coarsely structured hard layer will be precipitated than is the case when alloyed AICr targets are used.
Less suitable for this purpose, however, are processes known from the prior art in which, for example, the vaporization process of a least one component is difficult to manage or is intermittent, since no reproducible layer quality can be achieved thereby.

It is, of course, possible to produce layers of this kind using other vacuum coating machinery or, for example, by sputtering processes, although ionization of the process gases, which is in principle lower, must under certain circumstances be balanced out by known measures such as special adhesive layers, additional ionization, etc., in order to achieve comparable layer adhesion.
In principle, using the Cr~_XAIXN layers with a cubic structure it is possible to coat very different work pieces. Examples of these are cutting tools such as milling tools, hob cutters, round-head, flat, and profile milling tools, as well as drills, threading taps, reamers, and turnover cutting plates for turning and milling work, or forming tools such as, for example, stamps, matrices, drawing rings, ejector cores or thread formers.
Injection molding tools, for example, for metal injection molding alloys, plastics, or thermoplastic, in particular injection molding tools such as those used for producing molded plastic parts or data carriers such as CDs, DVDs etc., can also be used and can to advantage be protected by layers of this kind. A further range of applications includes components that demand wear resistance which under certain circumstances is coupled with great resistance to oxidation. For example, sealing rings, pistons, stamps, gear wheels, and valve gear such as barrel tappets and rocker arms, or needles for injectors, compressor shafts, pump spindles, or many components to which one or plurality of meshing elements are attached.
Additionally, because of the behavior of (AlyCr~_y) X layers, which is, in principle, similar, an improvement in wear behavior can also be anticipated if in the following layer systems target composition and coating parameters are so selected that a cubic layer structure is achieved.
(AlyCrl_y) X wherein X = N, C, B, CN, BN, CBN, NO, CO, BO, CNO, BNO, CBNO, preferably, however, N or CN , and 0.2 < Y < 0.7, preferably 0.40 < Y < 0.68 (A166Cr3q) NO layers with different N/0 ratios were deposited thus and then their Iayer properties were tested. The coating parameters were selected so as to be similar to those selected above. The total pressure was between 1 and 5 Pa at an oxygen flow between 20 and 60 scan (remainder nitrogen), the substrate voltage was between -40 to -150 V, the temperature was 450°C, and the source power at a current of 140 A was set at 3.5 kW.
This produced layers with O/N ratios of approximately 0.2, 0.6, and 2.2. The layers with the low oxygen content proved to be superior in different milling tests. The results were clearly better than the service lives achieved with conventional TiN or TiCN.
Because of the improved slip properties of the (AlyCr~_y) X layers discussed above, there is the possibility -- which is interesting from both economic and ecological standpoints -of dispensing with lubricants when operating tools, in particular cutting tools and forming tools, or else use only minimal quantities of such lubricants. From the economic standpoint, one must take into account the fact that the costs for cooling lubricant, in particular in the case of cutting tools, can be greater than the cost of the tool itself.
An even more far-reaching possibility for improving the slip properties of a layer system according to the present invention, which contains an (AlyCr~_y) X layer, will result if a slip layer is applied as the outermost layer. It is advantageous if the slip layer is of a lower hardness than the (AlyCr, _y) X layer and possesses break-in characteristics.
The slip-layer system can be built up from at least one metal or from a carbide of a least one metal and dispersed carbon, MeC/C, the metal being a metal from the group Nb, Vb and/or VIb and/or silicon. For example, a WC/C cover layer of a hardness that can be adjusted between 1000 and 1500 HV, and which possesses excellent break-in characteristics, is well-suited for this. Cr/C layers display a similar behavior, although at a somewhat higher coefficient of friction.
In the case of deep-hole drill bits coated in this way, after the production of one to three bore holes, it was possible to see excellent break-in smoothing which, up to now, could only be achieved by means of costly mechanical machining. Such properties are interesting, in particular, for component applications that are subjected to slip, friction, or rolling stresses, with little lubrication or when running dry, or if an uncoated opposing body is to be protected at the same time.
Additional possibilities for forming a finishing slip layer are metal-free, diamond-like, carbon layers, or layers containing MoSX, WSX, or MoSX or MoWX layers that contain titanium.
As discussed, the slip layer can be applied directly on the (AlyCr~_y) X layer or after application of an additional adhesive layer, which can be formed as metal, nitride, carbide, or carbon nitride, or as a gradient layer with, for example, a continuous transition between (AlyCr~ _y) X and slip layer, in order to bring about the best possible adhesion of the layer bond.
For example, after the application of a sputtered or arced Cr or Ti adhesive layer, WC/C
or CrC/C layers can be produced, advantageously by sputtering of WC targets during the addition of a gas that contains carbon, when the proportion of gas that contains carbon is increased over time in order to arrive at a greater proportion of free carbon in the layer.
Further advantageous applications for different (AlyCr~_y) X hard coated tools are described below, their use for different cutting operations serving as examples.
Example 1: Milling structural steel Tool: Shank-type cutter Diameter D = 8 mm, tooth count 3 Material: Ck 45 structural steel, DIN 1.1191 Milling parameters:
Cutting speed: v~ = 200/400 m/min Feed speed vt: 2388/4776 mm/min Width of radial contact a~: 0.5 mm Width of axial contact: ap: 10 mm Cooling: Emulsion 5%
Process: Constant speed milling Wear criterion: Free-surface wear VB = 0.12 mm ~ari.m~nt Meta~llanteil Standzeit N7C. IAt~E) : bei V8 Eohicht 0,12 amp O !,n titinuren ~ Ty Al Cx v ~ 200 v,. = C00 m/win ut/min 1 TiCN) I00 - - 71 9 2 (TiAlLIT 53 a7 d~ ~ 15 3 AI.CzN181 69.5 3p,5 167 4U

$ AlCZ2J)B4 72 2S dl 7 (AIC~i~T - 41,5 5$,5 ~,SO 1~

5 (111Ct~) - 19 81 3.9 d ~~

Key: 1 - Experiment Number; 2 - Proportion of metal (At%) Layer; 3 - Standard times t at VB = 0.12 mm in minutes Example 1 shows a comparison of the standard times of coated HM milling tools that were tested using different cut parameters.
It is clear that the AICrN layers referred to have longer service Lives as compared to the layer systems used in industry up to the present time, such as TiCN and TiAIN.
In addition, the results show that, as in Example 1, the service life behavior improves as the aluminum content increases, to the extent that the cubic B 1 structure is maintained, as is the case in Example 1 (compare Experiments No. 3, 5, 6). This can be attributed above all to the improved resistance to oxidation and hardness that can be seen with the increasing aluminum content (see Table 1). The very good resistance to oxidation of the AICrN coating becomes particularly noticeable in the range of dry and high-speed machining (e.g., v~ = 400 rpm). Furthermore, this test, too, shows that when the crystal lattice is collapsed from B 1 to B4, the structure of the wear behavior is degraded (compare Experiments 3 and 4).
Example 2: Milling austenitic steel Tool: Shank-type cutter, hard steel Diameter D = 8 mm, tooth count 3 Material: X 6 CrNiMoTi 17 12 2 austenitic steel, DIN 1.4571 Milling parameters:
Cutting speed v~ = 240 m/min Tooth feed speed f~~ = 0.08 mm Width of radial contact ap = 0.5 mm Width of axial contact: 10 mm Cooling: Emulsion 5%
Process: unidirectional milling Wear criterion: free-surface wear VB = O.lmm p~'Xm~TlL vt~tLtX~.t~TitCiJ (%'a.~;' ~ ~ Sttsncisaw~ 7:E boa 3Ii ~ t7. Z nuc:
I~Y, Sek~~ch~: in :r:e:t.~x~
'1'i t A1 i __._ _..
7 ('iXCtJ) 1.00 - f " .._...~i;' ..
8 {t332'.~.fiT) 35 ti5 ~ - 95 9 ~i.C:.'T~) Hl 69,5 - , :~G,:i:i~.
Key: 1 - Experiment Number; 2 - Proportion of metal (At%) Layer; 3 - Standard path lr at VB = 0.1 mm in meters Example 2 shows a comparison of the service lives of coated HM milling tools.
Here, in the same way as with the AICrN layer, it is possible to achieve an improvement of wear as compared to the layers of hard material used in industry. In the case of AICrN, the improvement in service life could be achieved, on the one hand, by a lesser inclination --as compared to the Ti in TiAIN layers -- of the second alloying element Cr to spread, which up to now remains unproved and, on the other hand, by the clearly good resistance to wear displayed by AICrN layers (A, B, D) according to the present invention, as set out in Table 1, at a simultaneously high degree of hardness.
Example 3: Milling hardened steel Tool: Ball-head cutter Diameter D = 10 mm, tooth count z = 2 Material: K 340 (62 HRC), corresponding to C 1.1%, Si 0.9%, Mn 0.4%, Cr 8.3%, Mo 2.1%, Mo2.1%, V 0.5%
Milling parameters:
Cutting speed v~ = 0 - 120 m/min Tooth feed speed fX = 0.1 mm Width of radial contact as = 0.2 mm Width of axial contact ap: 0.2 mm Cooling: Dry Process: Unidirectional and bidirectional milling, planishing Wear criterion: Free-surface wear VB = 0.3 mm i iWtell 9tendwe~ lc bei VH
LAtR~J a 0,3 ~
Metal7 ~~r . ~ ic. M~ce~;
meri,t sahicht ___ T A). ~r _ _.....

X.4 tTiA7.zaJ 53 a~ . ru ;

~1 t711crNl 69. 30, 90 a 5 5 Key: 1 - Experiment Number; 2 - Proportion of metal (At%) Layer; 3 - Standard path at VB = 0.3 mm in meters Example 4: Rough milling tool steel Tool: Shank-type cutter, hard steel Diameter D = 10 mm, tooth count z = 4 Material: X 38 tool steel X 38 CrMoV 5 1, DIN 1.2343 (50 HRC) Milling parameters:
Cutting speed v~ = 60 m/min Tooth feed speed fX = 0.02 mm Width of radial contact a~~ = 2 mm Width of axial contact ap: 10 mm Cooling: Dry Process: Unidirectional milling, roughing Wear criterion: Free-surface wear VB = 0.1 mm t~erimezW Dir_te2lcs~t~ai1 (~.~:~3 ~~~~:a:d~~ is ~u_ ,rte - ~,:1 ~,tx'- 9cYaChC ..~.._,..r ~..._~~'~' -m teaer:
~. ~ td~~.C xN ) 'E i _ ' ~?~ 3 C~ ; ~... ~---~, ;;
Key: 1 - Experiment Number; 2 - Proportion of metal (At%) Layer; 3 - Standard path at VB = 0.1 mm in meters Example 3 and Example 4 display an improved standard path of the AICrN layer as opposed to the TiAIN layers used in industry. AICrN is particularly well-suited for dry machining that imposes great demands with respect to resistance to oxidation and resistance to wear.
Example S: Drilling in tool steel Tool: HSS drill bit (S 6-5-2) Diameter D = 6 mm, Material: X 210 tool steel, Cr 12 DIN 1.2080 (230 HB) Cutting speed V~ = 35 m/min Drilling parameters:
Feed f = 0.12 mm Bore hole depth z = 15 mm, blind hole Cooling: Emulsion 5%
Wear criterion: torque shutoff (corresponding to erosion wear of >_ 0.3 mm $xporimeat Ns. Metallantci 8tnndwep~
[jt~[ ~ [Y
SehlCht a~h~nhl ! 1xm pl cr ,, Schiahtdiekel 14[AlCxN)H1 19 B1 21 15AlCz~N181 41 Sg , 52 5 5..-x6AlcrCN)81 4x.5 58,5 65 7,7(A1C7CN1H1 69.5 30.5 10B

i8AICrNIH4 72 a& Q6 Key: 1 - Experiment Number; 2 - Proportion of metal (At%) Layer; 3 - Standard path (hole count/p,m layer thickness) Example 6 shows a comparison of the hole count, standardized on the basis of layer thickness and achieved with HSS drill bits with AlyCr~_y N/ AlyCr~_y CN layers with different A1 contents.
The layers were produced with the parameters set out in Table 2. As the aluminum content increase, there was an increase in the service life up to not quite 70% aluminum in the metal content. In the case of a further increase, and thus the precipitation of a layer with an hexagonal crystal structure, performance falls off. In the range between 41.5 and 69.5% aluminum (Experiment 15, 17) it is possible to establish a clear increase in performance in this application as compared to the prior art (Experiment 18).
Example 6: Deep hole drilling 5 x D in Ck 45 Tool: Drill bit hard metal, Diameter D = 6.8 mm, Material: Structural steel, 1.1191 (Ck 45) Drilling parameters:
Cutting speed vs =120 m/min Feed f = 0.2 mm Bore hole depth z = 34 mm, blind hole Cooling: Emulsion 5%
Wear criterion: Erosion wear VB = 0.3 mm E~~timont Motallanteil 9te.ndz~tit t boi Hr. fRt%) VB ~ e,3 , ~ mm in 8ohiaht ~ Ti , Cr Aazahi Hohxit5cher a 1$ K~iAlN)'70 30 990 _ 53 " 47 ~1i35 19 tTiAI.N) 20 A7.CYN ~ 69 30 > 2128 Key: 1 - Experiment Number; 2 - Proportion of metal (At%) Layer; 3 - Standard time t at VB = 0.3 mm in number of bore holes Example 6 shows an improved service life of the AICrN layer as compared to the TiAIN
layers, as used industrially, in a drilling application. Here, the improved resistance to abrasive wear of the AICrN coating according to the present invention becomes obvious.
In addition, drill bits coated as in Experiment No. 20 were provided with a WC/carbon slip layer after application of a Cr adhesive layer, whereupon a clearly improved service life could be achieved under otherwise identical test conditions. Torque measurements conducted at the same time revealed a clearly smaller torque moment than is observed without a slip layer. In addition, it is possible to see a better surface quality and, until shortly before the end of the service life, no coloration brought about by excessive temperature stress.

Example 7: Tapping 2xD in austenitic steel Tool: HSS screw tap , thread dimension M8 Material: Austenitic steel, 1.4571 (X6CrNiMoTi 17/12/2) Drilling parameters:
Cutting speed v~ = 3 m/min Thread depth: 2XD
Thread type: blind hole Number of threads: 64 Cooling: Emulsion 5%
Wear criterion: Torque progression over thread count, visual assessment of wear after 64 threads.
~cv~riu~nt Mntallaxttoil .
Iix. tAt~

Schicht Ti A1 Cr m ~, Optiacher SchnittnsvrnentVaraahloi ~~ d ~" c zi tTica~rf xoo d. ~a Z2 AlCrN>Dl 69,5 30,5 4 05 __,-~*

~3 (AlCrtQ d7. 58.~ 4.23 +*~' ~1 5 2d X1G'rH7 19 B1 4 ~ 27 k~.

Key: 1 - Experiment Number; 2 - Proportion of metal (At%) Layer; 3 - Qj maximum cut moment (Nm); 4 - Visual wear (1) Explanation of (1) + Wear behaviour satisfactory during tapping ++ Wear behaviour good during tapping +++ Wear behaviour very good during tapping A reduction of the average maximal cutting moment is achieved with all the layers compared to the prior art. In addition, because of the very good wear resistance of the layers with the higher aluminum content, there is improved wear behavior compared to TiCN. Certainly, in this example, presumably because of the adhesive tendency of the aluminum, which leads to material spreading and subsequently to layer breakdown, the layer in Experiment 23 displayed a better wear image than Experiment 22.
Additionally, screw taps coated as in Experiment Nos. 22 and 23, were provided with a WC/carbon slip layer or, after application of a Ti adhesive layer, were provided with a MoS2 layer containing Ti, whereby an improvement in service life and better surface quality of the machined material could be achieved under otherwise equal test conditions.
Example 8: Hobbing in CrMo steel Tool: Hob milling machine Material: DIN 86-7-7-10 (ASP60) Diameter: D = 80 mm, length L = 240 mm, Modulus m = 1.5 25 chip grooves Angle of engagement a = 20°
Reference profile 2, tooth count 50, thread width 25 mm Material: Cr-Mo steel DIN 34CrMo4 Cutting parameters:
Cutting speed V~ = 260 m/min Feed: 2 mm/L1 Piece count: 300 Cooling: dry cut, compressed air to remove chips.
ExpsrimtntMotal.J.nnte varschi~ieeuarken l~r. (AtBI iCV i,n S~hicht n~tl f ~ Ti A7. Cx Prei~l~henv.ICellrvat ( achleiaa a5 (TiCD1)100 .0,32 0,062 Z6 (TiA1D1133 47 - O,aS U,UG2 t 77 RlC.xl~1 72 2U U. ~y 0 053 ~8 t3t.zCrN)Bi 19 81 U,d6 0,051 29 (R.lCsnJ')HJ. 41.,5 5B.5 G 13 0,022 3U (l~l.CrN)81- 69,5 90.5 9 lc M - p,018 Key: 1 - Experiment Number; 2 - Proportion of metal (At%) Layer; 3 - Width of wear marks in (mm); 4 - Free surface wear; 5 - Erosion wear In Tests 25 to 30, different hobbing cutters made from high-speed steel (HSS) produced by powder metallurgy and with different layer systems were tested during dry cutting. A
significant improvement as compared to known TiCN or TiAIN coated cutters could be achieved with tools coated as in the present invention (Experiment 29 and Experiment 30). In the same way, it must be acknowledged that AICrN layers with a low (No. 28) to high aluminum content offer a lesser degree of protection against wear if an hexagonal crystal structure is present (No. 27).
The following examples, Nos. 31 to 33, also shows the clear superiority of an AICrN
layer according to the present invention, with a cubic crystal lattice in the essentially stochiometric nitrogen proportion and an aluminum content of 66%. Milling cutters made from PM HSS or hard metal were tested both for dry and for emulsion-lubricated cutting.
Experiment No. 31: Hobbing Tool: PM HSS
Diameter: D = 80 mm, length L = 240 mm Cutting speed: 180 m/min (A1o.42Tio.ss)N~ balinite NANO: 1809 pieces (A10.63T1p.39)N, balinite X.CEED 2985 pieces 5370 pieces (Alo.6sCro.3~)N
Experiment No. 32 Hobbing Tool: Hard metal (HM) Diameter: D = 60 mm, length L = 245 mm Modulus: 1.5 Angle of engagement ??? = 20°
Material: 42 CrMo4 Cutting speed: 350 m/min, dry (Alo.4~Tio.39)N, balinite X.TREME 1722 pieces (Alo.ssTio.37)N~ balinite X.CEED 2791 pieces (A10.65Cr0.34)N > 3400 pieces Experiment No. 33: Hobbing Tool: PM HSS
Diameter: D = 80 mm, length L = 240 mm Modulus: 2.5 Material: 16MnCr5 Cutting speed: 140 m/min, emulsion TiCN, BALINITE B: 1406 pieces (A1o,42Tio.ss)N~ balinite NANO: 1331 pieces (A1o.66Cro.aa)N 1969 pieces Additional tests, not described herein, showed that even at still higher speeds, up to vs =
450 m/min, durability remained good. Standard times of hard-metal hob cutters could also be improved noticeably during wet and, in particular dry, machining.
Example 9: Rough milling tool steel Tool: Shank-type cutter Diameter D = 10 mm, tooth count z = 4 Material: X 40 tool steel CrMoV 5 l, DIN 1.2344 (36 HRC) Milling parameters:
Cutting speed v~ = 60 m/min Tooth feed speed fa = 0.05 mm Width of radial contact aX = 3 mm Width of axial contact ap: 5 mm Cooling: Emulsion 5%
Process: Unidirectional milling, roughing Wear criterion: Free-surface wear VB = 0.1 mm ExperimentMstallnrrreil 8tandwvg 1~ b~3 VB
isr. ~ JAtB = 0, 3, uun I
J is Miter ~ I
.
~
JchicBt Ti Al Cx ' 3A IhlTi 35 65 - 6 -W

35 (AlxtJN58 4a - 3 - 4 36 (AlTflCNSO 90 3 4 ~~ T~Crr ~.oo .. - s - i1 ...-38 AlCx HS 64 36 12 - 21 N

39 fA7,Cx u1~ 66 36 21 - Z8 N

40 tAlCr)1Q ~6 3a 12 - 1B

HS = Adhesive layer of TiN
puts = pulsed Key: 1 - Experiment Number; 2 - Proportion of metal (At%) Layer; 3 - Standard path 1 ~~~ at VB = 0.1 mm in meters Example 10: External machining of hardened carburizing steel Tool: Turning tool with soldered-in CBN insert Material: Carburizing steel I 6 MnCr 5, DIN 1.7131 (49 - 62 HRC) Turning parameters: hard-soft machining with interrupted cut and partially thinner wall thickness Cooling: dry Wear criterion: piece count up to achievement of free-surface wear of VB = 0.1 mm rxpoximemrMatallsnteil 9tandsneriGA boi v8 Nr. (hC8) ~ 0.1 ram ~
Scbicht ~ Ti A1 Cr 41 (AITi 35 65 - yo ' N -___ 42 AlCslN 66 34 ~.a4 I

Key: 1 - Experiment Number; 2 - Proportion of metal (At%) Layer; 3 - Standard quantity at VB = 0.1 mm in meters Similar results were also obtained with cermets produced by powder metallurgy consisting of a TiN, TiC, or a Ti(CN) hard phase, to which molybdenum and or tantulum was added. Ni or Ni/Co was used as a binding phase.

Example 11: Thread forming in galvanized steel Experiment No.: 43:
Tool: HSS MS thread former Material: DCO1 corresponding to DIN 1.0330 St 12 ZE
Tapping drill hole diameter: 8.34 mm Cutting parameter: 55 m/s Cutting speed: 2000 rpm Return speed: 3600 rpm Lubrication: S26 CA
TiN: 3200 threads TiCN 3200 threads TiAIN 3500 threads (Alo.~~Cro.3a)N 8800 threads Tests with coated CBN (cubic boron nitride) or cermet tools: turnover cutting plates of different CBN sintered materials with a CBN content between 30-99vo1-%, remainder binding agent, were coated, on the one hand, with known TiAIN layers as in Experiment 8, and, on the other hand, with AICrN layers as in Experiment 3, Experiments 3, and Experiment 6. Because of the non-conductive nature of the CBN sintered material, a pulsed substrate bias in the middle frequency range, preferably in a frequency range from 20 to 250 kHz, was applied for the etching and coating process.
For materials with a CBN content of up to 90%, a bonding agent powder was used that consisted of at least one of the elements from the following group: nitride, carbide, boride, and oxide of the Ti, V, or Cr group, i.e., IVa, Va, and VIa elements, as well as aluminum or aluminum compounds.
For materials with a CBN content of up to 95% a bonding agent powder was used that consisted of titanium nitride and the least one of the elements from the following group:
cobolt, nickel, wolfram carbide, aluminum, or an aluminum compound.

For materials with a CBN content of greater than 90%, a bonding agent powder was also used, consisting of titanium nitride and and at least one of the elements from the following group: boride or boron nitride of the alkali or earth-alkali metals.
During turning and milling tests conducted subsequently it was, in most instances, possible to see wear behavior that was greatly improved as compared to TiAIN
layers. It was the same in the course of a particularly exhaustive external machining test in which a shaft of complex geometry that was only partially hardened and was machined in part during interrupted cutting.
Example 12: Hot forging Tool: 4 forging jaws 220x43x30 mm, drill W350, hardness 54 HRC, 4 tools engaged simultaneously Work piece: round stock, diameter 22 mm, material 42 CrMo4 Method: Temperature of work piece before forming 1050°C Pressing force 57 t per jaw Cooling: Molicote + graphite F~cperim~atl4etallant~il x~r. (l~t~~ titnnc~nen~o Sch~cht ~ Ti A1 Cr Nh~Si v/w fStackxuhl?

43 uxabeuch.- 5U0 44 ~tAlN 58 42 900 n5 AlCrN da 36 1900 4b AICxVN 63 31 6 1500 4? AdCxSiNHS fi5 26 9 . 180ti 49 hl,CrN~P1'~=.-. __31...._7..... ., . ....... _...
- ..~2... .1~.~0",.._ ...._ .._._ d9 AICrWN 65 26 9 1630 0 7lacrYic 6Z 31 7 ' i9 3 0 51 AlCrMoI4 62 31 7 1469 HS = Adhesive layer of TiN
Key: 1 - Experiment Number; 2 - Proportion of metal (At%) Layer; 3 - Standard quantity (piece count) Example 13: Hot bordering Tool: HM flowdrill, diameter 10 mm Method: The tool was pressed against the work piece at 2800 rpm, at 3000 N.
The work piece was brought to red heat, i.e., approx. 1000°C and formed by kinetic energy.
t~cpsrirnentHetallaxiGeil .Nr. (At~t) :;t Q d ~chicht _ Ti ~ Cx on ~/simonqo V!W (Stuokzohil 1 5~ unZ~ach.- S00 b3 TiAlN 58 4a - 900..

5~ AlCrN 6a 36 i~aa 55 AICrVN 63 31 6 7.530 56 AiCrSiNHS 65 26 9 1650 57 AICzNbN- 62 31 7 1450 58 AlCs~WfP 55 25 9 1390 59 AlC b2 31 7 1f;60 YN

60 ALCxndorii 6~ 31 7 1340 HS = Adhesive layer of TiN
Key: 1 - Experiment Number; 2 - Proportion of metal (At%) Layer; 3 - Standard quantity (piece count) Example 14: Stamping Tool: 1.2379 slot punch 20 x 10 mm Work piece: TRIP 700, 1.2 mm thick Method: Shearing, cutting gap 10%, 500 strokes/min Cutting force: 20 kN
__~ -Ex~erituantt~lett~112tnteil .
nl5c. [At~E
~ Statida~an~o ~ ~
Schi.ebt __ ...._..._ ~i ...~_..._~~._-~ISi....._ ...._.
G~. utsba~aalz._ V/W ..
- St~ckzachl ) ~ 100000 , I

8~ TiAlH 5N is - 200090 63 AlCsT1 - 64 36 350000 64 AICrVDT 63 31 6 3!0000 65 AlCrBiIQHS 65 26 9 280000 65 AlCz~7b~N 62 31 7 300000 Cr5aN ~ 65 a6 9 aao00o I
67 h7 . - 63 __ _ 30000 68 AlC7CYN 31 7 sg AlC=HoA 52 ss ~ asocoo WO 2004/0659030 CA 02523882 2005-10-26 pCT/CH2004/000180 HS = Adhesive layer of TiN
! I ~ ~ I , l i tr. 1 r. i o v-t ~ r, rl rry ,: :-,.. ~ ~,:; ! r,.. 3. 4::
d ~ ~ ~ r:
r..~~::,~~.~~:i~~r 1 i t _. _., ~ i '"f ~--i-~~...._,_.
~ j . ..) . i .
~ ' ,.:; c i ,.i" ,-~i , a ~ ",'-y c:~ cv t nr ;,~ i 'ri i.
~ ~~ , ~ " , t ~ t ~ ~ !
r, i f~ ~. ,' ~; o cs ~ o o r~ o o c~ , i _.._............__.x....._. . _..._ E
,~t w ~ . M ~
rt sV t~ cY j t ~ r .~" tV t~ CO r~l : ~.._... '.
t ~ H ~ Zf M ~d' .", r tf iS~ : ~ C..T !~y~~~I,ft 'Vi ! ) : ._..~ : 'sv~ "V'~ 11' 'Cs ~ .. I
j ~ .
~, th j ~ u7 : .~.., .._~.
.~:
U ~ Ca rt P7 ; cC
:wf tt1 tPn tt7 ~ > v ~ 1 t ! i S r-1 ~ Cy ? i>'1 j _. t .-y"e_._ _ :.v..~.j Yi C~.~ p., i ~n .~t t ~n ! ~ m z s t ~ t ~ , ..... t j t --...fir , b ~ i ~ ., J i ;
i vr~r"tir"7~x"'a ~ ~ ...__' i ;i-»:.-J..... ~~.__.,.
4 a.e C. ~.'. ~ ! !
S Qt ~ i t~ ~.y ! N ~ ~ t 1 . rw; .
4> i ~ rw m a M ~ Ca rn w j "., i ,.,., n '".. w Cv t ' ' ' w s~ ~ U ~ ~ ~-i ."-"~ i ~ :~ a .d, ~ j ! rt: i, (° y v J. ~N-, ~ i l~' i ..
-.__.r..._.. I-i~~i.'-kt---~----I ~....._..i r? tn !~ N ~ ~ !
s a ~ ~:~ ~ i i .
7 ~ rC' ~ 4? ~ ~ . "' "', i L.., W,i Key: Key: 1 - Test Number; 2 - Proportion of metal (At%) Layer; 3 - Crystal structure; 4 - Layer thickness (gym); 5 - Adhesion

Claims

1. Work piece with a layer system that contains at least one layer of the composition (Al y Cr1-y) X with X = N, C, B, CN, BN, CBN, NO, CO, BO, CNO, BNO, or CBNO
and 0.2 <= y <0.7, the composition of the layer being either essentially constant within the layer itself or changing over the thickness of the layer continuously or incrementally, the work piece being one of the following tools, namely, a milling tool, in particularly a hobbing cutter, a round-head cutter, a planar cutter, or a profile cutter, a broaching cutter, a reamer, a turnover cutting plate for turning and milling, and a molding or injection-molding tool.

2. Work piece with a layer system that contains at least one layer of the composition (Al y Cr1-y) X with X = N, C, B, CN, BN, CBN, NO, CO, BO, CNO, BNO, or CBNO
and 0.2 <= y < 0.7, the composition of the layer being either essentially constant within the layer itself or changing over the thickness of the layer continuously or incrementally, the work piece being a structural element.

3. Structural element as defined in Claim 2, characterized in that the structural element is a sealing ring, a gear wheel, a piston, part of a valve system, or a needle for an injection nozzle, or is toothed.

4. Tool as defined in Claim 1, characterized in that the tool is a forming tool, in particular a stamp, matrix, a drawing ring, an injection core, a thread former, or a punch.

5. Tool as defined in Claim 1, characterized in that the tool is a hot-forming tool, in particular a forging tool, a bordering tool, or a punch.

6. Tool as defined in Claim 1, characterized in that the tool is an injection molding tool for producing a shaped plastic part or a data carrier.

7. tool as defined in Claim 1, characterized in that the tool has a CBN or cermet basic body or is a CBN or cermet turnover cutting plate.

8. Work piece as defined in one of the preceding claims, characterized in that the (Al y Cr1-y) X layer is present in a crystalline structure.

9. Work piece as defined in one of the preceding claims, characterized in that the rate of wear of the (Al y Cr1-y) X layer is more than or equal to m3m-1N-1 10 -15.

10. Work piece as defined in one of the preceding claims, characterized in that the Vickers hardness of the (Al y Cr1-y) X layer is 2300 to 3100.

11. Work piece as defined in one of the preceding claims, characterized in that the layer structure of the (Al y Cr1-y) X layer is microcrystalline and the mean grain size amounts to 20 to 120 nm.

12. Work piece as defined in one of the preceding claims, characterized in that an adhesive layer is applied between the work piece and the ((Al y Cr1-y) X
layer.

13. Work piece as defined in Claim 12, characterized in that the adhesive layer includes at least one of the metals of the IV, V, or VI subgroup, or aluminum.

14. Work piece as defined in one of the Claims 12 or 13, characterized in that the adhesive layer includes at least a nitride, carbide, or carbon nitride of one or a plurality of metals of the N, V, or VI subgroup.

15. Work piece as defined in one of the preceding claims, characterized in that in addition, a slip layer is deposited on a least one (Al y Cr1-y) X layer.

16. Work piece as defined in Claim 15, characterized in that the slip layer includes a carbide of a least one metal with dispersed carbon MoC/C, a diamond-like carbon layer, a diamond-like carbon layer that contains silicon or metal, an MoS x, a WS x or an MoS x on MoW x layer that contains titanium.

17. PVD method for depositing at least one (Al y Cr1-y) X layer on a work piece, with X =
N, C, B, CN, BN, CBN, NO, CO, BO, CNO, BNO, CBNO and 0.2 <= Y < 0.7, at least one work piece is built into a vacuum coating machinery with at least one Al x Cr1-x target with 0.25 <= z <= 0.75 at least one work piece is built in and at a pressure of 0.5 - 8 Pa is so driven during the addition of reactive gas that contains nitrogen, carbon, boron, or oxygen and with a substrate voltage between -3 to -150 V applied as an arc or sputter source that the layer composition within at least one (Al y Cr1-y) X layer changes either essentially constantly, or continuously or incrementally across the thickness of the layer.

18. PVD method as defined in Claim 12, characterized in that X = N and the reactive gas is nitrogen or oxygen.

19. PVD method as defined in Claim 17 to Claim 18, characterized in that the substrate voltage is pulsed.

20. PVD method as defined in Claims 17 to 19, characterized in that the Al y Cr1-y target is a target produced by powder metallurgy.

21. PVD method as defined in Claim 20, characterized in that a target is used that by mixing powdered starting materials is cold pressed and then and pressed by multiple reforming, for example in a forging press, at temperatures below 660°C
during flowing and cold welding, and is brought to an end state with a theoretical density of approximately 96 - 100%.

22. Method for machining a material, characterized in that a tool as defined in Claim 1 is used.

23. Method as defined in Claim 22, characterized in that the machining is done without the addition of lubricant or cooling agent.

24. Method as defined in Claims 22 to Claim 23, characterized them that the tool is a hard metal or HSS hobbing tool and the cutting speed amounts to 60 to 450 m/min.

25. Method as defined in Claim 22 to Claim 23, characterized in that the tool is a shank-type milling tool, a ball-head milling tool, or a rough-cutting milling tool.