|Publication number||US3297552 A|
|Publication date||Jan 10, 1967|
|Filing date||Aug 25, 1964|
|Priority date||Feb 25, 1963|
|Publication number||US 3297552 A, US 3297552A, US-A-3297552, US3297552 A, US3297552A|
|Inventors||Gisser Henry, Arthur M Shapiro|
|Original Assignee||Gisser Henry, Arthur M Shapiro|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (2), Referenced by (12), Classifications (14)|
|External Links: USPTO, USPTO Assignment, Espacenet|
' Jan. 10, 1967 GISSER ETAL 3,297,552
METHOD OF MAKING A TITANIUM PIECE HAVING GOOD ANTI-WEAR, ANTI-GALLING, ANTI-SEIZURE AND ANTI-FRICTION PROPERTIES Original Filed Feb. '25, 1963 IST NC FROM INVENTOR. HENRY GISSER ARTHUR SHAPIRO United States Patent 4 Claims. (Cl. 204-37) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to us of any royalty there- This invention is a divisional application of our co- ,pending patent application, Serial No. 260,925, filed February 25, 1963, entitled, Titanium Piece Having Good Anti-Wear, Anti'Galling, Anti-Seizure and Anti-Friction Properties, now abandoned, and relates to anti-wear and anti-friction alloy concentration gradients on titanium surfaces such that titanium pieces may be used satisfactorily in diverse machine applications.
It is well known that titanium is a relatively light metal, its specific gravity being only slightly greater than onehalf that of steel. Titanium possesses an exceptionally high strength to-weight ratio and good corrosion resistant properties which make it especially useful in various machine elements as in gearing and the like. Its frictional properties, wear and galling resistance, however, need considerable improvement if titanium is to advance its status in diversified machinery equipment.
Toward this end, much research has been directed to the development of suitable lubricants for titanium pieces which would aid in lowering its high ooefiicient of friction and thus minimize wear of moving parts. To date, however, no single lubricant has been found which will give good service when used with bare titanium metal.
It is therefore, a broad object of this invention to increase the usefulness of titanium metal in various machine elements.
Another object of the invention is to provide means for improving the friction and wear properties of titanium.
A more specific object of the invention is to improve the friction and wear properties of titanium by diffusing a second metal into the surfaces of the titanium.
Other and further objects of the invention will be apparent to those skilled in the art upon study of this disclosure and of the single drawing which graphically represents the variations in hardness of the alloy concentration gradients (or modified surfaces) of our new compositions.
We have discovered that when silver or gold is diffused into a titanium surface resulting in an alloy concentration gradient (see the hardness curves in the drawings) the surface (when appropriately lubricated) offers admirable anti-friction, anti-wear, anti-seizure and antigalling properties to the titanium, considerably simplifying the lubrication problem on the titanium surface.
Further, we have discovered that the titanium surfaces modified by the aforementioned metals as hereinabove described are receptive to lubrication by conventional lubricants and additives (see Tables III, III, IV and VI).
More specifically, when any of the two metals aforementioned are electroplated on titanium and the resulting piece is heated in an evacuated furnace, the electroplated surface of the titanium is provided with an alloy con- Patented Jan. 10, 1967 P? CC centration gradient having good anti-wear and anti-friction properties to thereby increase the usefulness of titanium machine elements.
A typically pure metal piece treated in accordance with our invention has the following physical properties given below by way of illustration.
Table I Tensile yield strength, p.s.i 76,700 Ultimate tensile strength, p.s.i 87,200 Tensile elongation in one inch, percent 23.5 Carbon content, percent 0.08 Nitrogen content, percent 0.02 Hydrogen content, percent 0.005
Grams Potassium cyanide (C.P.) 11 Gold (as potassium gold cyanide) 8.4 Distilled water to make 1 liter of solution.
The temperature of the bath was maintained between 60 and C. and a current density of about 2 to 3 arn.p./ft. was employed. Using a gold anode, anelectroplate of about 0.001 inch was obtained after about 2 hours.
In electroplating silver, the sandblasted titanium piece was immersed for about 10 seconds in a striking 'bath of:
02. Silver cyanide (tech.) 0.5 Sodium cyanide (tech.) 8.0
Distilled water to make 1 gallon.
The temperature of the striking bath was about 25 C. with a current density of 20 amp/ft The piece was then transferred to a plating bath having the composition:
02. Silver cyanide (tech.) 4.0 Potassium cyanide (C.P.) 7.5 Potassium carbonate 6.0
Distilled water to make 1 gallon.
The plating bath temperature may conveniently be about 25 C. while the current density approximates 4 am:p./ft. After 1 hour, a plate approximately 0.0005 inch thick was produced. Silver anodes were used in both the striking and plating baths.
The titanium pieces, having been plated with silver or gold to the thickness described in Tables 11 and III, were placed in a suitable electric oven or furnace which was then evacuated to about 10* mm. of mercury. The furnace temperature was raised from room temperature to about 860 C. in a period of 2 /2 to 3 hours, maintained at this temperature for a period of about 7 hours and the furnace allowed to cool gradually while still evacuated. The penetration of the alloying metal into the surface of the titanium may be seen from the drawing which shows that for each alloy the hardness first increases to a maximum then falls off and thereafter the hardness finally levels off generally to that of the titanium 6 metal itself. The depth of penetration for any of the metals used maybe seen from the drawing.
To show efiectiveness of the modified titanium surfaces as prepared above in reducing friction and wear, and in improving the load carrying capacity (e.g. cutting down seizing and galling) on the titanium surface, coefficient of friction tests, wear tests and extreme pressure tests were run and the resulting data are described in the following.
Before running the coefficient of friction, the treated titanium surface was ground down to a depth indicated in the tables. (This was done to insure that the tests were not being run on the unalloyed metal.) Coefiicient of friction was measured at several depths. It will be seen from Tables II and III that in every instance the measurement was made at a depth below the thickness of the original unditfused plating. The coefiicient of friction in Tables II and III are those for the sliding of 52100 steel over the treated titanium surface. Coefficients of friction were run on unlubricated surfaces, surfaces lubricated with cetane, and surfaces lubricated with various additives in cetane as shown in Tables II and III. By comparison of the figures obtained with the treated surfaces with those obtained with the untreated surface of titanium, it is seen that the coefiicient of friction is greatly reduced in many instances. It was found that when the coefiicient of friction on untreated titanium was run, there was extensive stick-slip. This was not the case with many of the treated surfaces. The Tables also shown that the treated surfaces has become susceptible to lowering the coefficient of friction by the addition of active additives.
TABLE II.C ()EFFICIENTS OF FRICTION MEASUREMENTS OF MODIFIED TITANIUM SURFACES WITH VARIOUS LUBRICANTS -Smo0th sliding.
ties of the gold and silver treated titanium surfaces as compared with untreated titanium surfaces.
TABLE IV.FOUR BALL WEAR TEST Failure Time, minutes Alloying Metal Load,
Cetane Diisopropyl 1 Benzyl Phosphite Disulphide None g Gold 50 "i5 "at Silver 40 20 1 2% solution in cetane. 2 Immediate.
TABLE V.SGAR DEPTH lIgSTTHE FOUR BALL WEAR AlloyingMetal Load, Kg. Scar depth, in.
Gold 10 0. 0015*0. 0005 20 0. 0O25:l;0. 0005 Silver 30 0. 002i0. 0005 In Table VI below, excellent anti wear anti-seizure and anti-galling properties of our gold modified titanium surface are shown. The data were obtained on a Falex \Vear Tester.
The tests were conducted using jaw blocks made from FS2320 steel and pins made from 75 A. titanium. The jaw load was increased from zero to 250 pounds by engaging the eccentric arm of the rachet wheel. When TABLE III.COEFFICIENT OF FRICTION MEASUREMENTS OF MODIFIED TITANIUM SURFACES WITH VARIOUS LUB RICANTS Alloying Original Metal Plating Depth, Tncresyl 1 Octyl 1 42% Benzyl l I-Iexachloro- Diisopropyl 1 Thickness, in. Phosphate Mercaptan Chlorinated 1 Disulphide Ethane Phosphate in. Parallin None 0.001 0.22 0.20 0.24 0.20 0.25 0.23 Silver 0.0005 0.0005 0.11 0.20 0.13 0.17 0.25 0.0s 0.0015 0.25 0.21 0.21 0.21 0.19 0.22 Gold. 0.001 0.0005 000 0.09 0.00 008 0.09 0.11 0.0015 0.09 0.12 0.21 0.19 012 0.09 0.0025 "0.28 -0.29 =0.20 0.21 0.24 0.24
1 2% in cetane. SticksIip. Smooth sliding.
Wear tests were run on the well known Four Ball the jaw load reached 250 pounds the eccentric arm was Wear Tester at 600 r.p.m. and 20 to 25 C. The upper disengaged and the load maintained for one minute. and lower balls were inch diameter commercially pure Using the same procedure, the jaw load was increased in titanium (75 A.). Surfaces were alloyed in accordance increments of 250 pounds until failure occurred.
with the aforedescribed procedures. Except for titanium which failed at a 2 kilogram load, the tests were run at intervals of 10 kilograms for one hour. If no failure occurred in one hour, the positions of the balls were changed so that fresh surfaces were exposed and the test continued at the next higher load. Accordingly, when failure times for any load are given in Table IV, it means that at a load of 10 kilograms less, there was no failure for a period of one (1) hour.
Table IV shows the excellent wear resistance proper- TABLE VL-FALEX WEAR TEST ONMODIFIED TITANIUM SURFACES Cetane Diisopropyl Bennyl Phosphite 2% Disulphide 2% in Cetane in Cetane Pin Wear, Failure, Wear Failure Wear Failue lbs. lbs.
Titanium 0 0 0 0 0 0 Gold"--- 2, 250 3, 000 1, 500 2, 750 2, 000 3, 000
It is apparent therefore that through the practice of our invention the usefulness of titanium has been considerably extended. When lubricated as aforedescribed, although not limited to the specific lubricant compositions described herein, the modified titanium surfaces exhibit anti-wear, anti-galling, anti-seizure and anti-friction properties not heretofore realized in the use of titanium.
1. A method for producing a machinable titanium piece having on its surface a thin layer of a noble metal selected from the group consisting of gold and silver and between said layer and titanium base a thicker alloy concentration gradient of titanium and said noble metal, said gradient having a hardness exceeding the hardness of said titanium base over a major portion thereof, said method comprising the steps of:
electroplating said piece with said noble metal,
gradually and strongly heating the electroplated piece in vacuo from room temperature,
holding the electroplated piece in vacuo in its strongly heated state, and
allowing the piece to cool gradually in vacuo.
2. The method as described in claim 1 wherein said electroplated piece is gradually and strongly heated in vacuo from room temperature to a final temperature of about 860 C. over a period of about 2 /2 hours and wherein said heated electroplated piece is held in vacuo at about 860 C. for about 7 hours.
3. A method as described in claim 1 wherein said metal consists of gold and said electroplating step is carried on until about 0.001 inch of gold electroplate results.
4. A method as described in claim 1 wherein said metal consists of silver and said electroplating step is carried on until about 0.0005 inch of silver electroplate results.
References Cited by the Examiner UNITED STATES PATENTS 2/1956 Hands 204--46 X 7/1962 Finlay 29198 X
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US2734837 *||Sep 27, 1954||Feb 14, 1956||Surface treatment of titanium or|
|US3045333 *||Oct 18, 1951||Jul 24, 1962||Rem Cru Titanium Inc||Titanium coated article|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US3471342 *||Jul 29, 1966||Oct 7, 1969||Ibm||Wear-resistant titanium and titanium alloys and method for producing same|
|US3522974 *||Jun 20, 1968||Aug 4, 1970||Stephanois Rech Mec||Friction pair adapted to operate without lubrication|
|US3535007 *||Jul 3, 1968||Oct 20, 1970||Klingler Emil A||Bearing|
|US3866518 *||Dec 27, 1972||Feb 18, 1975||Aisin Seiki||Fluid pressure device of the axial plunger type|
|US4137370 *||Aug 16, 1977||Jan 30, 1979||The United States Of America As Represented By The Secretary Of The Air Force||Titanium and titanium alloys ion plated with noble metals and their alloys|
|US4614445 *||Nov 2, 1984||Sep 30, 1986||U.S. Philips Corporation||Metal-lubricated helical-groove bearing comprising an anti-wetting layer|
|US4818469 *||Oct 27, 1986||Apr 4, 1989||Deutsche Gesellschaft Fur Wiederaufarbeitung Von Kernbrennstoffen Mbh||Seal for turning valve bodies, in particular for valves in nuclear-engineering plants|
|US4848934 *||Jan 11, 1985||Jul 18, 1989||The Boeing Company||Lightweight high performance titanium sliding contact bearing|
|US5292596 *||Aug 19, 1992||Mar 8, 1994||United Technologies Corporation||Force-transmitting surfaces of titanium protected from pretting fatigue by a coating of Co-Ni-Fe|
|US5484665 *||Apr 15, 1991||Jan 16, 1996||General Electric Company||Rotary seal member and method for making|
|US5545431 *||Jun 7, 1995||Aug 13, 1996||General Electric Company||Method for making a rotary seal membrane|
|US9192973||Mar 13, 2013||Nov 24, 2015||Meier Tool & Engineering, Inc.||Drawing process for titanium|
|U.S. Classification||205/228, 384/912, 428/935, 428/673, 428/660, 428/672|
|International Classification||C25D5/50, C25D7/10|
|Cooperative Classification||C25D7/10, Y10S384/912, Y10S428/935, C25D5/50|
|European Classification||C25D5/50, C25D7/10|