US3132927A - Wear-resistant material - Google Patents

Description

May 12, 1964 w. G. BORNER 3,132,927

WEAR-RESISTANT MATERIAL Filed July 31, 1961 5 Sheets-Sheet 1 May 12, 1964 w. G. BORNER 3,132,927

WEAR-RESISTANT MATERIAL Filed July 3l, 1961 5 Sheets-Sheet 2 .ODI

ALUM/NUM M54@ u, y A /0 ./o /V/C/fz WEAR o x ff IO 2O 30 40 .50 60 70 5544/06 S7-9655 PSI X /03 Fi S.

.O04` ALUM/NUM A454@ Q .oo- WEA@ ATTUQNE'Y May 12, 1964 W. G. BORNER WEAR-RESISTANT MATERIAL Filed July 51, 1961 ze s .00,

E S k i) O 3 Sheets-Sheet 3 IO 2O 30 40 50 60 70 Bew/NG 6719665 Rs/ A /O 3 Ti fl INVENTOR. M1. L/AM G. 50e/ys@ aware, was entirely successful when carried into United States Patent O 3,132,927 WEAR-RESISTANT MATERIAL William G. Borner, Fair Haven, NJ., assignor to The International Nickel Company, Inc., New York, NX., a corporation of Delaware Filed July 31, 1961, Ser. No. 128,158 3 Claims. (Cl. 29-'183.5)

The present invention relates to wear-resistant materials and, more particularly, to wear-resistant coatings, and a process for making said wear-resistant coatings.

It is well known that wear is attrition and/ or impairment due to use. It is also well known that wherever there is relative motion and contact, ie., dynamic contact, between two or more bodies there is wear. Thus, the principal cause of wear is friction. While it is clear that friction cannot be completely eliminated between moving bodies, there has been a never-ending search for means to abate the amount of wear since wear costs industry millions of dollars annually. Among the factors which must be taken into account whenever it is desired to obviate the deleterious effects of wear are lubrication, temperature, mechanical impact, thermal shock, time, vibration, surface speeds, etc. In many cases, however, the nature of the operation precludes the designer from altering many, if not all, of these factors.

In such cases, then, the designer must direct his attention to the compositions of materialsA andattempt to find those materials which are compatible with other materials. oftentimes, the material having optimum wear properties is, however, prohibitively expensive. Conversely, those materials which are inexpensive are usually not the ones having the best wear properties. Although many attempts were made to provide an inexpensive material having good wear properties, none, as far as I am practice commercially on an industrial scale.

It has now been discovered that unique materials` and/or coatings having excellent resistance to wear'rnay` now be produced by electrodeposition under specially 40 controlled conditions.

Itnis an object of the present invention to provideimyproved and novel coatings which are, even in the asplated condition, unexpectedlyV resistant to wear, abrasion and/ or attrition. 45

It is another object of the'present invention to provide unique electrodeposited coatings on aluminum to movek with continuous compatibility against cast aluminum.

The invention also contemplates providing an irnproved process for producing wear-resistant coatings and/ or materials.

Other objects and advantages will become' apparent from the following description taken in conjunction with the accompanying drawing in which: A

FIGURE l is a pen andink drawing of a photomicrograph taken at a magnilication of 250'diameters (250x) of an. unetched wearresistant coating within the scope of the present invention;

FIGURE 2 is a graphical representation showing the low cumulative wear of a wear-resistant coating made in accordance with the present invention under varying bearing stresses against cast-aluminum which also had low cumulative wear; p

FIGURE 3 is also a graph showing the higher cumulative wear of cast aluminum in contact with cast alumi# num under several bearing stresses under oil lubricated conditions;

FIGURE 4 is a plot of cumulative wear with oil lubri- 3,132,927. Patented May l2, 1964 cation at various bearing stresses for cast aluminum contacting a hard nickel coating outside the scope of this invention;

FIGURE 5 is a graph depicting the corresponding high cumulative wear when a coating not within the scope of the presentinvention was used; Y

FIGURE 6 is, similarly, Ystill another graph illustrating the high cumulative wear versus bearing stresses when another coatingnot within the contemplation of this invention wasused; and A A Y FIGURE 7 is, like FIGURES 5 and 6, a graph showing the high cumulative wear versus bearing stresses when still another coating not within this inventionwas used.

Generally speaking, the present invention contemplateselectrodeposited materials and/or coatings having excellent resistance to wear even in the as-plated condition which coatings contain about l% to about 20% by weight of particulate mica, each of said particles having a mean major dimension of about 5 to about 45 microns, and,- advantageously, about7 to about 40 microns, with the balance essentially a continuous matrix of an electrodeposited metal having a melting point in excess of about C. and having a standard electrode potential of less than about +08 volt according to the electromotive series. The mica of the coating is substantially uniformly dispersed throughout the metal matrix as discrete particles having a substantially similar laminar orientation one with the other andwith the surface to be subjected to wear, i.e., the mica particles are manifestly oriented in approximately parallel' relationship, such as illustrated in FIG. l. In such an orientation, the plate-like particles of mica have predominantly similar directional relation to eachother.

The mica of the coatings can be in the form of synthetic micas and/or natural micas, including the heptaphyllites such as muscovite and paragonite, the octophyllites suchas lepidolite, phlogopite and'biotite, the soda-micas, the lithia-micas, the magnesia-micas, the ferro-micas, the mica-like minerals such as vermiculite and combinations thereof. As was mentioned"l1ereinbefore, the mica is present in the coatings in amounts ranging from about '1% to about 20% by weight and advanta- Vgeously in amounts of about,2% `to 10% lby weight. If

less than 1% is present, the characteristics, including wear characteristics,-=of the coatings are merely those of the matrix metal. If more than 20% is present, the materiall is substantially weakened. Furthermore, if. the mean particle A size of the mica is notin the range of about 5 to aboutl 45 microns, the properties of the coating will deteriorate.`

For example, if the particle size is less than about 5 microns, substantially no improved wear resistance swobtained. On the other hand, y than about 45 microns, the coating is rough and is only weakly adherent. For optimum wearability, the mica is advantageously present in amounts ranging from about 2% to about 10% by weight and its mean particle size lies between about 7 microns and 40 microns.

Advantageously, the matrix is a metal selected from the group consisting of nickel, cobalt,'iron and copper. More advantageously, the matrix metal is nickel because of its remarkable compatibilitywhen used in accordance with the invention with most materials, its excellent corrosion-resistance characteristics and its ease of high quality electrodeposition. Other metals having a melting point in excess of 150 AC. and a standard electrode potential of less than about-10.8 vol-t canl if the particle size is greaterl the metals which are included as those itemized in Table I:

TABLE I the matrix metal are Standard electrode potential at 25 C.

in volts Metal Palladium Platinum Gold (auric) Gold (aurons) The present invention also contemplates a process for producing the Wear-resistant materials and/or coatings of the present invention lhaving compositions both within the broad and advantageous ranges. According to this process, an electrically conductive surface is made the cathode of an electrolytic cell and is immersed in an electrolyte containing ions of a metal as described hereinbefore, i.e., a metal having a standard electrode potential of less than about +08 volt at 25 C. and a melting point in excess of about 150 C., and containing about 1% to about 10% by volume, advantageously about 2% to about 5%, of mica having a particle size of between about 5 microns and about 45 microns suspended or dispersed in said electrolyte. The mica is caused to contact the cathode, eg., by rotation of the cathode and/ or by agitation, circulation or the like of the elec- .ftrolyte, while an electrodepositing electric current is passed through the cell in a manner well known in electroplating to produce a coating containing about 1% =to about by Weight mica having a particle size (i.e., major dimension) of about 5 microns to about 45 microns with the balance essentially an electrodeposited metal of the character described hereinbefore while maintaining the particulate mica dispersed in the electrolyte. The electrolyte can be any available electrolyte which will deposit lthe matrix metal. As has been mentioned, the metal is advantageously selected from the group consisting of nickel, cobalt, copper, iron and combinations thereof.

As previously stated, the electrodeposited matrix metal is more 'advantageously nickel. The plating baths and/ or electrolytes for use in depositing a nickel electroplate con-taining mica in accordance with the invention include those which are listed compositionally in the following Table II:

TABLE II Weight of const., ounces/gallon of Bath Constituents ofbath water Type ofbath No. inaddition to mica Range Example Nickel sulfate.- 25-50---. 40 1 Nickel chloride. Upto 12- 6 Watts type.

Boric acid Upto 7. 4-5 Nickel sulfate- 1040---- 32 2 Nickel chloride-.- 10-40 12 High chloride.

ic e ori eo O-- 32 s {seriada-faan t l Amm i0 1c e uo ora e o 4 {Boric acid 31:0 7.- 4 imuoborate 5 {Nickel suliamatc ltoSO.. t0 }Hardnickcl Boric acid 3ro 7.- 4 ,sulfamate It is to be appreciated that variations may be mad@ 75 in the baths listed in Table Il as those skilled in the art will readily understand. For example, brighteners such as naphthalene disulfonic acid, saccharin, butyndiol, etc., may be added -to any of the baths of Table II. In addition, levelling agents such as coumarin, etc., and antipitting agents such as sodium lauryl sulfate, etc., may also be added to any of the baths of Table Il. Of course, other nickel plating baths or electrolytes can also be used.

Satisfactory operating conditions for the deposition of nickel coatings containing mica by electroplating from the baths of Table II are hereinafter set forth in Table *As measured by quinllydrone glass electrode.

Representative plating baths for depositing other metal coatings containing mica within the scope of the present invention are listed in the following Table IV:

TABLE IV B ath No.

constituents of bath in addition to mica Weight, ounces] gallon of Water A Metal deposited Cobalt sulfate Sodium chloride. Berio acid Nickel sulfate Nickel chloride-.

Cobaltv sulfate- Boric acid Zinc cyanide-- Sodium cyanid Rochelle salt. Ammonia (28%) Hydrotluoric acid VResorcinol. .Ammonium nitrate- Sodium nitrate Pla Ammonium hydroxide (28%) Palladium, as palladium chloride p `ammonium chloride tinum diammino-nitrite Cobalt.

Nickel-18% Cobalt.

han.

}Coppcr. Copper.

Brass.

Zine.

Cadmium.

l l l l }Cliromium.

lfrmuum.

Palladium.

Satisfactory operating conditions for the deposition of metals containing mica by electroplating from the baths of Table IV are set forth in Table V:

1 VA=very acidic.

2 VB=ver`y basic.

The unique compositions of the present inventions can be electrodeposited onto various basis metals such as aluminum, iron, stainless steel, brass, copper, nickel, etc. Alternatively, the materials can be electrodeposited onto a base then stripped off, e.g., onto a suitable stainless steel surface or a graphitized surface.

In carrying the invention into practice, it is advantageous to incorporate the mica as a dispersion in the electrolyte. In order to assure that the mica is suspended in the electrolyte solution and does not settle out (otherwise little of the mica will be codeposited with the metal) the electrolyte should be agitated as by vibration, circulation, rotation of cathode, etc., as those skilled in the art readily understand, to provide a dispersed system of mica in the electrolyte in contact with the cathode.

For the purpose of giving those skilled in the art a better understanding of the invention, the following illustrative example is given:

Example A cast aluminum article, containing about 3% copper, about 9% silicon, with the balance essentially aluminum, 2.352 inches in diameter by 0.394 inch wide was cleaned in alkali to blacken it. The article was then dipped in a solution containing nitric acid and hydrofluoric acid, water rinsed-and placed in a bath containing Zinc oxide in caustic soda. Thereafter, the aluminum article was rinsed in water and then in a 5% solution of sulfuric acid. The article was then again rinsed in water and made the cathode in a hard nickel bath containing about 40 ounces of nickel sulfamate and about 4 ounces of boric acid per gallon of water. The pH of the electrolyte was determined electrometrically to be about 4. Mica having a particle size of between about 7 microns and about 40 microns was then suspended in the electrolyte so that it comprised about 2% by volume of the bath. The bath was then provided with a nickel anode and it was then heated to about 140 F. and maintained at that temperature throughout the plating operation. During the electroplating operation the cathode was rotated at about 0.5 surface foot per minute. A cathode current density of 40 amperes per square foot (asf.) was applied to the electrolyte and was continued for about 3 hours. The cathode was then removed from the bath and it was determined that the coating was about 6 mils thick. The unetched coated aluminum cathode was then observed under a microscope at a magnication of 250 showing, as illustrated by FIGURE 1 (a pen and ink drawing of the photomicrcgraph), a coating 11 containing a nickel matrix 12 and lamellae of particulate mica 13 substan- 6 tially uniformly dispersed throughout the nickel matrix. It is to be observed that the preponderance of discrete mica particles have similar directional orientation to each other and to the article surface 14.

After presoaking in turbine oil, having a viscosity of 305 Saybolt seconds at F. and 50.8 Saybolt seconds at 210 F., this coated aluminum article was tested in air using an Amsler wear tester which is described in detail in an article entitled Some Important Variables Encountered in Wear Testson Cast Iron, by D. E. Ackerman, published by the American Society for Testing Materials, 1937, page 24 et seq. The machine has two parallel shafts on which'were placed the coated aluminum article and another aluminum d-isc having the samecomposition and dimensions as the aluminum article which was coated in the manner hereinbefore set forth. The peripheries of the coated aluminum article and disc were made to contact each other. The gearing was set for this example, and for the other tests hereinafter set forth, so that one shaft turned at 440 revolutions per minute (r.p.m.), while the other turned in the same direction at 400 r.p.m. Thus, the aluminum article and disc were operated under conditions of slip with respect to' each other at the Wearing surfaces, i.e., equivalent tov a speed of travel of about 512 feet per minute. The aluminum article and disc were rst run in dynamic contact with each other at a bearing stress of 10,000 pounds per square inch'(p.s.i.) for 24 hours, which is equivalent to a surface travel of about 737,000 feet. This was considered to be a wearing-in period.V The aluminum article and disc were then wiped clean and measured with a micrometer to determine the change in diameter. The article and disc were then placed back in the Amsler wear tester and were run for 1 hour intervals (30,700 feet traveled) at successively higher stresses. At the end of each l hour interval the article and disc were measured with a micrometer to measure the change in diameter. The total wear, i.e., cumulative wear, was then determined by subtracting the diameter after testing from the original diameter. The results are plotted in FIG, 2 wherein the cumulative wear is the ordinate and bearing stress the abscissa. All bearing stresses are in thousands of pounds per square inch based on an unworn specimen. It is to be noted that there was substantially no wear until the bearing stress was at least about 50,000 pounds per square inch. Furthermore, the advantages of the present invention are clearly evident in that even at the higher loads the cumulative wear of the mating material and the coated test block remain substantially constant. In addition, inspection of the aluminum article and disc showed no scoring whatsoever.

In order to further show the advantages of the present invention a number of other wear tests were run. For example, cast aluminum having a composition substantially identical to the cast aluminum of the example was wear tested under identical test conditions against itself and yielded the results shown in FIG. 3. The aluminum when run against itself severely scored and eventually galled.

Another comparative test was conducted using a hard mica-free nickel plate deposited on an aluminum test block (cathode) from an electrolyte containing about 40 ounces of nickel sulfamate and about 4 ounces of boric acid per gallon of water. The plating conditions were identical to the example. The coating was found to be about 21/2 mils thick. It had a Knoop hardness of about 550 under a 100() gram load. The nickel-coated test block was then tested against cast aluminum in the same manner as hereinbefore illustrated in the example. However, in this test turbine oil lubricationwas used. The results are shown in FIG. 4. Although the nickel-coated article did not wear, the aluminum did wear excessively. In addition, the wear of the aluminum increased directly with increasing loads indicating that this type of coating would be unsuitable as a Wear resistant surface.

Another test was run on the Amsler wear tester in the manner set forth' in the example Withan aluminum test block which was chromium plated from a water solution containing 'about 32 ounces of chromic acid per gallon of Water and about 0.32 ounce of sulfuric acid per gallon of water. The temperature of the bath was 110 F. and the current density was 200 a.s.f. The results of these Wear tests against kaluminum with turbine oil lubrication are plotted in FIG. 5. The chromium coating showed an improvement over the aluminum wearing against aluminum (FIG. 3) but, nevertheless, yielded excessive Wear and scoring of the aluminum.

A nickel coating containing 18% silicon carbide having a particle size o f between about 7 microns and about 40 microns was electrodeposited on aluminum. The testing of this sample against aluminum was conducted under identical conditions as the example except that the blocks were turbine oil lubricated. The results are reported in FIG. 6. For bearing loads in excess of about 40,000 pounds, the aluminum Wore excessively as illustrated in FIG. 6. In addition, visual examination showed scoring of the aluminum.

When the previous test was repeated except that a nickel coating containing 7% by weight spheroidal aluminum oxide having a particle size of about 7 to about 40 microns was run against aluminum the results Were sim ilarly unsatisfactory as illustrated by FIG. 7. l It is to be noted that the coating of the present invention has superior Wear characteristics when compared with other coatings as demonstrated by the :foregoing tests and as illustrated in FIGS. 2 to 7 inclusive. In addition, the electrodeposited coatings of the present invention range in thickness from very thin, eg., at least about 1 mil, to very thick, eg., about 1 inch or even 11/2 inches.

The present invention is particularly applicable to the electroplating and/ or electroforming of articles which are to be subjected to extensive wear, e.g., bearings, bearing surfaces, etc. Specifically, the present invention is most advantageously applicable to the formation of coatings which are subjected to wear by dynamic contact with aluminum articles, eg., pistons, piston rings and/ or cylmajor dimension of about 5 microns to about 45 microns inder walls in engines. In additionythe present invention is applicable to a variety of other uses, c g., film guide for photographicV equipment, etc.'

Although the present invention has been described in conjunction with preferred embodiments, it is to be understood that modications and variations may be resorted.

to without departing from the spirit and scope of the invention as those skilled in the art will readily understand. Such modiications and variations are considered to be Within the purview and scope of the invention and ap- 2. A Wear-resistant assembly according to claim 1 wherein the electrodeposited nickel contains'about 2% to about 10% by Weight of particulate mica lamellae.

3. A wear-resistant assembly according to claim 2 wherein the mica particles have a mean major dimension of about 7 microns to about 40 microns.

References Cited in the file of this patent UNITED STATES PATENTS 2,177,853 Wills Oct. 31, 1939 2,504,239 Roehl Apr. 18, 1950 2,513,280 Brown July 4, 1950' 2,673,480 Wellman Mar. 30, i954 2,763,919 Kempe et al. Sept. 25, 1956 V2,775,531 Montgomery Dec. 25, 1956A 2,799,081 Farnham July 16, 1957 2,898,279 Metcalfe Aug` 4, 1959 UNITED STATES PATENT OFFICE CERTIFICATE 0E CORRECTION Patent No. 3,132,927 May l2, 1964 William G. Borner It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 3, TABLE I', second column thereof, opposite "Platinum", for "836" read 863 column 4I, TABLE IV,

second Column, seventh line from the bottom, for "Sodium nitrate" read Sodium nitrite Signed and sealed this 20th day of October 1964c SEAL) Anest:

RNEST W. SWIDER EDWARD J. BRENNER testing Officer Commissioner of Patents

Claims (1)

1. A WEAR-RESISTANT ASSEMBLY COMPRISING AN ALUMINUM MEMBER ADAPTED TO DYNAMICALLY CONTACT A MEMBER HAVING A SURFACE COMPRISED OF ELECTRODEPOSITED NICKEL CONTAINING ABOUT 1% TO ABOUT 20% BY WEIGHT OF PARTICULATE LAMELLAE OF MICA UNIFORMLY DISPERSED THROUGHOUT THE NICKEL AS DISCRETE PARTICLES HAVING PREDOMINANTLY SIMILAR DIRECTIONAL RELATION TO EACH OTHER AND SUBSTANTIALLY PARALLEL TO SAID NICKEL SURFACE, EACH OF SAID MICA PARTICLES HAVING A MEAN MAJOR DIMENSION OF ABOUT 5 MICRONS TO ABOUT 45 MICRONS.

Images