Screening tests have to be conducted during validation of the design of a machine componentand/or during the development and selection of materials, coatings, and surface treatmentsfor a particular application. These screening tests include accelerated friction and wear tests(including corrosion tests) and functional tests (Bhushan and Gupta, 1997). Simulated ac-celerated friction and wear tests are conducted to rank the candidate designs of a machinecomponent or candidate materials. Accelerated tests are inexpensive and fast. After the designsand/or materials have been ranked by accelerated friction and wear tests, the most promisingcandidates (typically from 1 to 3) are tested in the actual machine under actual operatingconditions (functional tests). In order to reduce test duration in functional tests, the tests canbe conducted for times shorter than the end-of-life. By collecting friction and wear data atintermediate intervals, end-of-life can be predicted.Accelerated friction and wear tests should accurately simulate the operating conditions
to which the component will be subjected. If these tests are properly simulated, an accel-eration factor between the simulated test and the functional test can be empirically deter-mined so that the subsequent functional tests can be minimized, saving considerable test time.Standardization, repeatability, short testing time, and simplemeasuring and ranking techniquesare desirable in these accelerated tests.This chapter presents a review of accelerated friction and wear-test methods. It presents the
design methodology and typical test geometries for friction and wear tests.
11.2 Design Methodology
The design methodology of a friction and wear test consists of four basic elements: simulation;acceleration; specimen preparation; and friction and wear measurements. Simulation is themost critical, but no other elements should be overlooked.
Proper simulation ensures that the wear a mechanism experienced in the test is identical to thatof the actual system. Given the complexity of wear processes and the incomplete understandingof wear mechanisms, test development is subject to trial and error and is dependent on thecapabilities of the developer. The starting point in simulation is the collection of available dataon the actual system and test system. A successful simulation requires similarity between thefunctions of the actual system and those of the test system, i.e., similarity of inputs and outputsand of the functional input–output relations.To obtain this similarity, selection of the test geometry is a critical factor in simulating
wear conditions. Generally, in laboratory testing for sliding contacts, three types of contact areemployed: point contact (such as ball-on-disk), line contact (such as cylinder-on-disk), andconforming contact (such as flat-on-flat). Selection of the geometry depends on the geometryof the function to be simulated. Each of these contact geometries has its advantages anddisadvantages. Point-contact geometry eliminates alignment problems and allows wear to bestudied from the initial stages of the test. However, the stress level changes as the matingsurfaces wear out. Conforming-contact tests generally allow the mating parts to wear in toestablish a uniform and stable contact geometry before taking data. As a result, it is difficult toidentifywear-in phenomena, because there is no elaborate regularmonitoring ofwear behavior.Other factors besides contact type that significantly influence the success of a simulation
include type of motion, load, speed, lubrication condition, and operating environment (con-tamination, temperature, and humidity). The type of motion that exists in the actual systemis one of four basic types: sliding; rolling; spin; and impact. These motions can be simulatedby performing wear tests under unidirectional, reciprocating, and oscillating (reciprocatingwith a high frequency and low amplitude) motions and combinations thereof. Load conditionsare simulated by applying static or dynamic load by dead weight, spring, hydraulic means,or electromagnetic means. Lubrication (or lack thereof), temperature, and humidity also con-siderably influence the friction and wear characteristics of certain materials. The ambienttemperature and contact temperature determine the thermal state of the system and should beprecisely simulated and controlled during the test. Measurements at the surface of a specimencan be made with thermocouples, thermistors, or infrared (IR) methods. Thermocouples arethe cheapest and simplest to use, and IR methods are the most accurate but complicated.Humidity affects chemical reactions which occur at a moving interface.
11.2.2 Acceleration
Accelerated tests are extremely inexpensive and fast. However, if the acceleration is not doneproperly, the wear mechanism to be simulated may change. Accelerated wear is normallycaused by increasing load, speed, or temperature, by decreasing the amount of lubricant inlubricated interfaces, and by continuous operation.
11.2.3 Specimen Preparation
Specimen preparation plays a key role in obtaining repeatable/reproducible results. However,specimen preparation may vary depending on the type of material tested. For metals, surface
Friction and Wear Screening Test Methods 617
roughness, geometry of the specimen,microstructure, homogeneity, hardness, and the presenceof surface layers must be controlled carefully for both the mating materials. Similar controlsare necessary for the wear-causing medium. For instance, in an abrasive wear test, purity,particle size, particle shape, and moisture content of the abrasive must be controlled.
11.2.4 Friction and Wear Measurements
The coefficient of friction is calculated from the ratio of friction force to applied normal force.The stationary member of the material pair is mounted on a flexible member, and the frictionalforce (force required to restrain the stationary member) is measured using the strain gages(known as strain-gage transducers) or displacement gages (based on capacitance or opticalmethods) (Doeblin, 1990). Under certain conditions, piezoelectric force transducers (mostlyfor dynamic measurements) are also used for friction-force measurements (Bhushan, 1980).Examples of two accelerated pin/ball on flat/disk tests are shown in Figure 11.2.1. In these
tests, a flat or a disk can reciprocate or rotate. Figure 11.2.1a shows the reciprocating stagewhich can be replaced with a rotating stage for unidirectional slidingmotion. In both examples,strain-gage beams are used to measure friction force during a sliding test. In Figure 11.2.1a,normal load is applied by dead weight loading and a strain-gage ring is used to measure thefriction force. In Figure 11.2.1b, normal load is applied by a microactuator and both normaland friction forces are measured by using a structure with two crossed I beams. For highsensitivity, semiconductor strain-gages with a gage factor of 115 or larger, as compared to 2.1for resistive gages, can be used.In the case of fibers, belts, and tapes wrapped around a cylinder, the coefficient of friction
(μ) is measured by using the belt equation, μ = (1/θ )�n (T/T0), where θ is the wrap angleand T0 and T are the inlet and exit tensions (T > T0) (Bhushan, 1996). The coefficient of staticfriction of particles against a flat surface can be measured by utilization of the centrifugalforce experienced by a rotating body (e.g., see Dunkin and Kim, 1996). A particle is placedon a disk which is rotated at increasing speeds until the particle flies off due to centrifugalaction. At an angular speed at which the particle starts to fly off, the centrifugal force justexceeds the friction force. For a particle flying off at an angular speed (ω) and radial locationof the particle (r), μs = ω2r/g. The angular speed can be obtained by videotaping the particleduring the test.Commonly used wear measurement techniques are weight loss, volume loss or wear scar
width or depth, or other geometric measures and indirect measurements such as time re-quired to wear through a coating or load required to cause severe wear or a change in surfacefinish. Scanning electron microscopy (SEM), scanning tunneling microscopy (STM), andatomic force microscopy (AFM) of worn surfaces are commonly used to measure microscopicwear. Other less commonly used techniques include radioactive decay. The resolutions ofseveral techniques are presented in Table 11.2.1 (Bhushan, 1996). For applications requir-ing low particulate contamination, particle counts are measured by using a particle counter(Bhushan, 1996).Weight-loss measurements are suitable for large amounts of wear. However, weight-loss
measurements have two major limitations. First, wear is related primarily to the volume ofmaterial removed or displaced. Thus such methods may furnish different results if materialsto be compared differ in density. Second, this measurement does not account for wear by
618 Introduction to Tribology
Figure 11.2.1 Schematics of accelerated friction and wear tests (a) with a strain-gage ring and deadweight normal loading, and (b) with a crossed I-beam strain gage transducer and microactuator loading.
Friction and Wear Screening Test Methods 619
Table 11.2.1 Resolutions of several wear-measurement techniques.
Measurement technique Resolution
Weight loss 10–100 μgRadioactive decay ∼1 pgStylus and optical profilers 0.5–10 nmMicrohardness indentation 25–50 nmNanoscratch technique 1–10 nmScanning electron microscope 0.1 nmScanning tunneling microscope/atomicforce microscope
0.05–0.1 nm
material displacement, that is, a specimen may gain weight by transfer. Thus weight-lossmeasurements are valid only when density remains constant and transfer does not occurduring the wear process. This technique is not sensitive enough for tests being conductedat low load and/or short time or in the case of thin wear-resistant coatings, where wear isvery small.A stylus or noncontact optical profiler and Vickers or Knoop microhardness indentation
techniques are easy to use and are commonly used to measure depth of wear with a resolutionof up to a fraction of a nanometer. An example of a wear-track profile obtained with astylus profiler is shown in Figure 11.2.2. Three-dimensional worn-surface profiles also can beobtainedwith fully automated profilers. In themicrohardness indentation technique, Vickers orKnoop indentations are made on the wear surface. By measuring the width of the indentationsbefore and after the wear test under a microscope, the wear depth can be calculated (Bhushanand Martin, 1988). In the nanoscratch technique, a nanoscratch is made with a conical tipusing a nanoindenter at low loads (Bhushan and Lowry, 1995). Measurement of the depth ofthe nanoscratch before and after the wear test, using an AFM, gives the wear depth.For measurements of microscopic wear, SEM, STM, and AFM of worn surfaces are com-
monly used (Bhushan, 1996, 1999). Radioactive decay (also called autoradiography) is verysensitive, but it requires facilities to irradiate one of the members and to measure the changesin radiation (Rabinowicz and Tabor, 1951; Bhushan et al., 1986). If particulate contaminationis an issue such as in gas-lubricated bearings, a particle count is also made during the test.Particle counters measure the number of particles per unit volume and their size distribution.Laser particle counters measure the particles in the range of 0.1–7.5 μm by the principle oflight scattering (Bhushan, 1996). A small volume of air (a few cc/s) containing particles to besampled is brought into contact with the particle-detecting optical system that measures thescattered light.
11.3 Typical Test Geometries11.3.1 Sliding Friction and Wear Tests
Many accelerated test apparatuses are commercially available that allow control of suchfactors as sample geometry, applied load, sliding velocity, ambient temperature, and humidity.Benzing et al. (1976), Bayer (1976, 1979, 1982), Clauss (1972), Nicoll (1983), Bhushan
620 Introduction to Tribology
Figure 11.2.2 Example of a wear-track profile obtained by a stylus profiler.
(1987), Yust and Bayer (1988), Bhushan and Gupta (1997), and Bhushan (2001) have reviewedthe various friction and wear test apparatuses that have been used in various tribologicalapplications. The most commonly used interface geometries for screening component designsand materials are shown in Figure 11.3.1 and are compared in Table 11.3.1 Many of thetest configurations are one-of-a-kind machines; others are available as commercial units fromsuch companies as Falex-Le Valley Corporation, Downers Grove, Illinois, Cameron PlintTribology, Berkshire, UK, Swansea Tribology Center, Swansea, UK, Optimol InstrumentsGmbH,Munich, Germany, and CSEM,Neuchatel, Switzerland. However, testing is not limitedto such equipment; tests often are performed with replicas and facsimiles of actual devices.Brief descriptions of the typical test geometries, illustrated in Figure 11.3.1 and comparedin Table 11.3.1, are presented in the following subsections. Static or dynamic loading can beapplied in any of the test geometries.
11.3.1.1 Pin-on-Disk (Face Loaded)
In the pin-on-disk test apparatus, the pin is held stationary and the disk rotates, Figure 11.3.1a.The pin can be a nonrotating ball, a hemispherically tipped rider, a flat-ended cylinder, or evena rectangular parallelepiped. This test apparatus is probably the most commonly used duringthe development of materials for tribological applications.
Friction and Wear Screening Test Methods 621
Figure 11.3.1 Schematic illustrations of typical interface geometries used for sliding friction andwear tests: (a) pin-on-disk, (b) pin-on-flat, (c) pin-on-cylinder, (d) thrust washers, (e) pin-into-bushing,(f) rectangular flats on rotating cylinder, (g) crossed cylinders, and (h) four-ball.
11.3.1.2 Pin-on-Flat (Reciprocating)
In the pin-on-flat test apparatus, a flat moves relative to a stationary pin in reciprocatingmotion,such as in a Bowden and Leben apparatus, Figure 11.3.1b. In some cases, the flat is stationaryand the pin reciprocates. The pin can be a ball, a hemispherically tipped pin, or a flat-endedcylinder. By using a small oscillation amplitude at high frequency, fretting wear experimentscan be conducted.
622 Introduction to Tribology
Table 11.3.1 Some details of typical test geometries for friction and wear testing.
oscillating8. Four balls Point Unidirectional sliding
asee Figure 11.3.1Type of Loading: Static, dynamic.
11.3.1.3 Pin-on-Cylinder (Edge Loaded)
The pin-on-cylinder test apparatus is similar to the pin-on-disk apparatus, except that loadingof the pin is perpendicular to the axis of rotation or oscillation, Figure 11.3.1c. The pin can beflat or hemispherically tipped.
11.3.1.4 Thrust Washers (Face Loaded)
In the thrust-washer test apparatus, the flat surface of a washer (disk or cylinder) rotatesor oscillates on the flat surface of a stationary washer, such as in the Alpha model LFW-3,Figure 11.3.1d. The testers are face loaded because the load is applied parallel to the axis ofrotation. The washers may be solid or annular. This configuration is most common for testingmaterials for low-stress applications, such as journal bearings and face seals.
11.3.1.5 Pin-into-Bushing (Edge Loaded)
In the pin-into-bushing test apparatus, the axial force necessary to press an oversized pin intoa bushing is measured, such as in the Alpha model LFW-4, Figure 11.3.1e. The normal (axial)force acts in the radial direction and tends to expand the bushing; this radial force can becalculated from the material properties, the interference, and the change in the bushing’s outerdiameter. Dividing the axial force by the radial force gives the coefficient of friction.
11.3.1.6 Rectangular Flats on a Rotating Cylinder (Edge Loaded)
In the rectangular-flats-on-a-rotating-cylinder test apparatus, two rectangular flats are loadedperpendicular to the axis of rotation or oscillation of the disk, Figure 11.3.1f. This apparatusincludes some of the most widely used configurations, such as the Hohman A-6 tester. In the
Friction and Wear Screening Test Methods 623
Alpha model LFW-1 or the Timken tester, only one flat is pressed against the cylinder. Themajor difference between Alpha and Timken testers is in the loading system. In the Falextester, a rotating pin is sandwiched between two V-shaped (instead of flat) blocks so that thereare four lines of contact with the pin. In the Almon-Wieland tester, a rotating pin is sandwichedbetween two conforming bearing shells.
11.3.1.7 Crossed Cylinders
The crossed-cylinders test apparatus consists of a hollow (water-cooled) or solid cylinder asthe stationary wear member and a solid cylinder as the rotating or oscillating wear member thatoperates at 90◦ to the stationary member, such as in the Reichert wear tester, Figure 11.3.1g.
11.3.1.8 Four Ball
The four-ball test apparatus, also called the Shell four-ball tester, consists of four balls in theconfiguration of an equilateral tetrahedron, Figure 11.3.1h. The upper ball rotates and rubsagainst the lower three balls, which are held in a fixed position.
11.3.2 Abrasion Tests
Abrasion tests include two-body and three-body tests. In a two-body abrasion test, one of themoving members is abrasive. In a three-body abrasion test, abrasive particles are introducedat the interface. Abrasion tests can be conducted using any of the so-called conventional testgeometries just described, with one of the surfaces being made of abrasive material or in thepresence of abrasive particles. A few commonly used specialized tests are described here.
11.3.2.1 Taber Abrasion Test
The Taber tester (manufactured by Teledyne Taber, North Tonawanda, NY) is widely usedfor determining the abrasion resistance of various materials and coatings. Test specimens(typically 100 mm square or 110 mm in diameter) are placed on the abrader turntable andare subjected to the rubbing action of a pair of rotating abrasive wheels (resilient calibrade,nonresilient calibrade, wool felt, plain rubber, and tungsten carbide) at known weights (250,500, or 1000 g), Figure 11.3.2a. Wear action results when a pair of abrasive wheels is rotatedin opposite directions by a turntable on which the specimen material is mounted. The abradingwheels travel on the material about a horizontal axis displaced tangentially from the axis ofthe test material, which results in a sliding action. Results are evaluated by four differentmethods: end point or general breakdown of the material, comparison of weight loss betweenmaterials of the same specific gravity, volume loss in materials of different specific gravities,and measuring the depth of wear.The Taber abrasion test provides a technique for conducting comparative wear performance
evaluations with an intralaboratory precision of +15%. These tests are commonly used byindustry, government agencies, and research institutions for product development, testing, andevaluation.
624 Introduction to Tribology
Figure 11.3.2 Schematic illustrations of abrasion test apparatuses: (a) two abradent wheels weightedon test specimen driven in opposite directions in the Taber abrasion test apparatus, (b) abrasive belt testapparatus, (c) dry-sand abrasion test apparatus, (d) wet-sand abrasion test apparatus.
11.3.2.2 Abrasive Belt Test
A flat-ended block or cylindrical specimen is abraded by sliding against an abrasive belt,Figure 11.3.2b. The belt runs horizontally, while the specimen runs transversely across thebelt. The specimen also can be rotated during this abrasion test (Benzing et al., 1976).
11.3.2.3 Dry-Sand Abrasion Test
In the dry-sand abrasion or dry-sand rubber-wheel abrasion test apparatus (ASTM G65), thespecimen is loaded against the rotating rubber wheel, Figure 11.3.2c. The load is applied alongthe horizontal diametral line of the wheel. The abrasive is gravity-fed into the vee formed atthe contact between the sample block and the wheel. The abrasive is typically 50–70 mesh(200–300 μm) dry American Foundry Society (AFS) test sand. Specimen weight loss is usedas a measure of abrasive wear (Bayer, 1982).
11.3.2.4 Wet-Sand Abrasion Test
In the wet-sand abrasion test apparatus, also known as the SAE wet-sand rubber-wheel testapparatus, the specimen is pressed against the rubber wheel, Figure 11.3.2d. It consists ofa neoprene rubber rim on a steel hub that rotates through a silica-sand slurry. The wheelhas stirring paddles on each side to agitate the slurry as it rotates. Sand is carried by the
Friction and Wear Screening Test Methods 625
rubber wheel to the interface between it and the test specimen. The slurry consists of 940 g ofdeionized water and 1500 g of AFS 50–70 mesh silica test sand. Specimen weight loss is usedas a measure of abrasive wear (Bayer, 1982).
11.3.2.5 Mar-Resistance Abrasion Test
The mar-resistance abrasion test apparatus, also called the falling silicon carbide test apparatus(ASTM D673), simulates abrasive wear resulting from the impingement or impact of coarse,hard silicon carbide particles. The test involves allowing a weighed amount of no. 80 siliconcarbide grit to fall through a glass tube and strike the surface of a test specimen at a 45◦ angle.The abrasion resistance is determined by measuring the percent change in haze of the abradedtest specimen by ASTM D1003 (Bayer, 1982).
11.3.3 Rolling-Contact Fatigue Tests
A number of rolling-contact fatigue (RCF) tests are used for testing materials and lubricantsfor rolling-contact applications such as antifriction bearings and gears.
11.3.3.1 Disk-on-Disk
The disk-on-disk test apparatus uses two disks or a ball-on-disk rotating against each other ontheir outer surfaces (edge loaded), Figure 11.3.3a. The disk samples may be crowned or flat.Usually, the samples rotate at different sliding speeds to produce some relative sliding (slip)at the interface (Benzing et al., 1976).
11.3.3.2 Rotating Four Ball
The rotating four-ball test apparatus consists of four balls in the configuration of an equilateraltetrahedron, Figure 11.3.3b. The rotating upper ball is dead weight-loaded against the threesupport balls (positioned 120◦ apart), which orbit the upper ball in rotating contact. In sometests, five balls instead of four balls are used. Also, in some studies, the lower balls are clamped(Bhushan and Sibley, 1982).
11.3.3.3 Rolling-Element-on-Flat
The rolling-element-on-flat test apparatus consists of three balls or rollers equispaced bya retainer that are loaded between a stationary flat washer and a rotating grooved washer,Figure 11.3.3c. The rotating washer produces ball motion and serves to transmit load to theballs and the flat washer (Bhushan and Sibley, 1982).
11.3.4 Solid-Particle Erosion Test
Erosion testing is generally conducted at room temperature using an air-blast test apparatus,shown in Figure 11.3.4. The tester is operated by feeding the eroding particles from a vibrating
626 Introduction to Tribology
Figure 11.3.3 Schematic diagram of three types of rolling-contact fatigue test apparatus: (a) disk-on-disk, (b) rotating four ball, (c) balls-on-flat.
hopper into a stream of gas. A known amount of eroding particles is directed onto one or moretest specimens. The weight loss of the test specimens is used as a measure of erosive wear(Bayer, 1976).
11.3.5 Corrosion Tests
Corrosion can occur because of electrochemical or chemical interactions with the environment.Electrochemical corrosion, also called electrolytic corrosion (EC), and accelerated businessenvironment (ABE) tests are used to test specimens. The EC test, where the test time is a fewminutes, is used to rank specimens that corrode by electrochemical means. These tests areuseful during early development. In the ABE test, the test time can be from a fraction of a day
Friction and Wear Screening Test Methods 627
Figure 11.3.4 Schematic diagram of solid-particle erosion test apparatus.
to several days depending on the environmental conditions. A properly simulated ABE test isgenerally used to predict the component life under actual conditions (Bhushan, 1996).
11.3.5.1 Electrochemical (EC) Test
In this test, two- or three-electrode cells are normally used to measure (1) the corrosionpotential to determine the practical nobility of a material, and (2) the corrosion-current densityto determine the corrosion rate of two dissimilar materials to determine the corrosion rate of amaterial couple (Bhushan, 1996). A number of electrochemical instruments are commerciallyavailable for EC tests (Dean et al., 1970).
11.3.5.2 Accelerated Business Environment (ABE) Test
The test samples are exposed to a controlled accelerated corrosive environment representativeof the business environment. The degradation of the test specimen in the corrosive envi-ronmental test is measured by various methods, such as measuring weight loss, quantifyingdimensional changes, noting changes in physical or chemical properties, measuring the sizeand number of defects on the surface using optical or scanning electron microscopes (visualmethods), determining the total defect density by light-scattering techniques, determiningthe atomic concentration of substrate material on a coated surface (chemical analysis), andquantifying performance degradation (if measurable). Commonly used corrosion tests thatapproximate the corrosion produced in service are discussed here. Frequently, combinationsof corrosive environments are used.
628 Introduction to Tribology
Salt Spray (Fog)The neutral salt-spray (fog) test utilizes a box of suitable size, from about 2 m3 to walk-insize, into which a 5% NaCl solution is aspirated with air. A common testing time is 72 hours,although exposure duration can vary considerably (ASTM B117-73). This test is commonlyused for zinc coatings (Saur, 1975). For corrosion tests of gas-turbine components, salts suchas Na2SO4 and NaCl are added in air (Nicoll, 1983).
SeawaterThe test samples are partially or completely submerged in natural or synthetic (ASTMD1141-52) seawater for a fraction of a day to several months. This method is commonly used formarine applications (Bhushan and Dashnaw, 1981; Bhushan and Winn, 1981).
Corrosive GasesIn this test, the test specimen is exposed to an accelerated corrosive gas environment (withconstituents representative of the business environment). The corrosive gases may consist ofsmall fractions of Cl2, NO2, H2S and SO2 (such as air with 5 ppb Cl2, 500 ppb NO2, 35 ppbH2S, and 275 ppb SO2 at 70% relative humidity and 25◦C). An exposure of a fraction of a dayto few days is sufficient (Bhushan, 1996).
Temperature/Humidity (T/H)In this test, test specimens are exposed to high temperature (T) and/or high humidity (H) fora fraction of a day to several days (Nicoll, 1983; Bhushan, 1996).
11.4 Closure
The screening tests include accelerated friction and wear tests and functional tests. Acceleratedtests are required to reduce the number of options in the design of a machine component and/ormaterials (typically from one to three). Then functional tests are conducted on a smaller sampleset. Accelerated tests reduce the testing time and cost. The accelerated tests serve a necessaryfunction; however, these should be designed so that they properly simulate wear mechanismsand at the same time accelerate the wear process. If these tests are properly simulated, anacceleration factor between the simulated test and the functional test can be empiricallydetermined to predict the component life based on the accelerated tests.
References
Bayer, R.G. (1976), Selection and Use of Wear Tests for Metals, STP-615, ASTM, Philadelphia, Pennsylvania.Bayer, R.G. (1979), Wear Tests for Plastics: Selection and Use, STP-701, ASTM, Philadelphia, Pennsylvania.Bayer, R.G. (1982), Selection and Use of Wear Tests for Coatings, STP-769, ASTM, Philadelphia, Pennsylvania.Benzing, R.J., Goldblatt, I., Hopkins, V., Jamison, W., Mecklenburg, K., and Peterson, M.B. (1976), Friction and
Wear Devices, Second edition, ASLE, Park Ridge, Illinois.Bhushan, B. (1980), “Stick-Slip Induced Noise Generation in Water-Lubricated Compliant Rubber Bearings,” ASME
J. Tribol. 102, 201–212.Bhushan, B. (1987), “Overview of Coating Materials, Surface Treatments, and Screening Techniques for Tribological
Applications Part 2: Screening Techniques,” In Testing of Metallic and Inorganic Coatings (W.B. Harding andG.A. DiBari, eds), STP-947, pp. 310–319, ASTM, Philadelphia, Pennsylvania.
Friction and Wear Screening Test Methods 629
Bhushan, B. (1996), Tribology and Mechanics of Magnetic Storage Devices, Second edition, Springer-Verlag,New York.
Bhushan, B. (1999), Handbook of Micro/Nanotribology, Second edition, CRC Press, Boca Raton, Florida.Bhushan, B. (2001),Modern Tribology Handbook, Vol. 1: Principles of Tribology, CRC Press, Boca Raton, Florida.Bhushan, B. and Dashnaw, F. (1981), “Material Study for Advanced Stern-tube Bearings and Face Seals,” ASLE
Trans. 24, 398–409.Bhushan, B. and Gupta, B.K. (1997),Handbook of Tribology: Materials, Coatings, and Surface Treatments, McGraw-
Hill, New York (1991); Reprint edition, Krieger, Malabar, Florida (1997).Bhushan, B. and Lowry, J.A. (1995), “Friction and Wear Studies of Various Head Materials and Magnetic Tapes in a
Linear Mode Accelerated Test Using a New Nano-Scratch Wear Measurement Technique,”Wear. 190, 1–15.Bhushan, B. and Martin, R.J. (1988), “Accelerated Wear Test Using Magnetic-Particle Slurries,” Tribol. Trans. 31,
228–238.Bhushan, B. and Sibley, L.B. (1982), “Silicon Nitride Rolling Bearings for Extreme Operating Conditions,” ASLE
Trans. 25, 417–428.Bhushan, B. and Winn, L.W. (1981), “Material Study for Advanced Stern-tube Lip Seals,” ASLE Trans. 24, 410–422.Bhushan, B., Nelson, G.W., and Wacks, M.E. (1986), “Head-Wear Measurements by Autoradiography of Worn
Magnetic Tapes,” ASME J. Tribol. 108, 241–255.Clauss, F.J. (1972), Solid Lubrication and Self-Lubricated Solids, Academic, New York.Dean, S.W., France, W.D., and Ketcham, S.J. (1970), “Electrochemical Methods of Testing,” paper presented at the
symposium on State of the Art in Corrosion Testing Methods, ASTM Annual Meeting, Toronto, Canada.Doeblin, E.O. (1990),Measurement Systems: Application and Design, Fourth edition, McGraw-Hill, New York.Dunkin, J.E. and Kim, D.E. (1996), “Measurement of Static Friction Coefficient Between Flat Surfaces,” Wear. 193,
186–192.Nicoll, A.R. (1983), “A Survey of Methods Used for the Performance Evaluation of High Temperature Coatings,” In
Coatings for High Temperature Applications (E. Lang. ed), pp. 269–339, Applied Science Publishers, London.Rabinowicz, E. and Tabor, D. (1951), “Metallic Transfer Between Sliding Metals: An Autoradiographic Study,” Proc.
R. Soc. Lond. A 208, 455–475.Saur, R.L. (1975), “Corrosion Testing: Protective and Decorative Coatings,” In Properties of Electrodeposits: Their
Measurements and Significance (R. Sard, H. Leidheiser, and F. Ogburn, eds), pp. 170–186, The AmericanElectrochemical Society, Princeton, New Jersey.
Yust, C.S. and Bayer, R.G. (1988), Selection and Use of Wear Tests for Ceramics, STP-1010, ASTM, Philadelphia,Pennsylvania.
Further Reading
Bayer, R.G. (1976), Selection and Use of Wear Tests for Metals, STP-615, ASTM, Philadelphia, Pennsylvania.Bayer, R.G. (1979), Wear Tests for Plastics: Selection and Use, STP-701, ASTM, Philadelphia, Pennsylvania.Bayer, R.G. (1982), Selection and Use of Wear Tests for Coatings, STP-769, ASTM, Philadelphia, Pennsylvania.Benzing, R.J., Goldblatt, I., Hopkins, V., Jamison, W., Mecklenburg, K., and Peterson, M.B. (1976), Friction and
Wear Devices, Second edition, ASLE, Park Ridge, Illinois.Bhushan, B. (1987), “Overview of Coating Materials, Surface Treatments, and Screening Techniques for Tribological
Applications Part 2: Screening Techniques,” In Testing of Metallic and Inorganic Coatings (W.B. Harding andG.A. DiBari, eds), STP-947, pp. 310–319, ASTM, Philadelphia, Pennsylvania.
Bhushan, B. (1996), Tribology and Mechanics of Magnetic Storage Devices, Second edition, Springer-Verlag,New York.
Bhushan, B. (2001),Modern Tribology Handbook, Vol. 1: Principles of Tribology, CRC Press, Boca Raton, Florida.Bhushan, B. (2011), Nanotribology and Nanomechanis II, Third edition, Springer-Verlag, Heidelberg, Germany.Bhushan, B. and Gupta, B.K. (1997),Handbook of Tribology: Materials, Coatings, and Surface Treatments, McGraw-
Hill, New York (1991); Reprint edition, Krieger, Malabar, Florida (1997).Clauss, F.J. (1972), Solid Lubrication and Self-Lubricated Solids, Academic, New York.Nicoll, A.R. (1983), “A Survey of Methods Used for the Performance Evaluation of High Temperature Coatings,” In
Coatings for High Temperature Applications (E. Lang. ed), pp. 269–339, Applied Science Publishers, London.Yust, C.S. and Bayer, R.G. (1988), Selection and Use of Wear Tests for Ceramics, STP-1010, ASTM, Philadelphia,
