Friction and Wear Behavior of Electroplated and Thermal Sprayed Coatings Tested in an Instrumented Rubber Wheel Abrasion Test

Abstract

This paper presents the results of a three-body abrasive wear and friction study of two different coatings on steel substrates. An instrumented rubber wheel abrasion test (RWAT) was used. One coating was thermally-sprayed WC-12 %Co, using the high-velocity oxygen fuel (HVOF) process, and the other coating was applied as electroplated hard chrome. Unlike current RWAT equipment, the apparatus described here has computer control of load and speed as well as instrumentation to measure specimen temperature and friction force. The instrument was calibrated using quenched and tempered D2 tool steel, per ASTM G 65-94. Tests of the thermally-sprayed coating were performed with loads of 65 or 130 N, and tests of the hard chrome plating used Procedure E of the standard. The wear resistance of the thermally-sprayed coating was dependent on substrate (52100 or 1020 steel) and it was in general superior to that for the hard chrome. The friction coefficients ranged between about 0.4 and 0.6 for the coatings against flowing sand. The tests performed with an applied load of 130 N did not meet the recommendation of ASTM on the coefficient of variation, and probably low loads should be considered in the standard to determine the wear resistance of coatings.

Abrasion and corrosion resistance of new Ni–based coating deposited by HVOF thermal spray process

“…The run-in period in the instrumented rubber wheel abrasion test has been discussed elsewhere. 21 In a general way, the friction behaviour was similar for all tested specimens. Table 3 presents the results of mass loss and average friction values obtained during tests with the instrumented rubber wheel apparatus.…”

“…20 The reason for this is the smaller coefficient of variation obtained by Pintaude et al 21 for HVOF coatings under tests performed with 65 N load. The effect of substrate properties was the other reason why Pintaude et al 21 used a lower test load. They verified the substrate effect (52100 or 1020 steel) on the friction and wear behaviour of HVOF WC-Co coatings.…”

“…20,21 The abrasive material employed was foundry sand with 99?8% silica content, with an average sand particle size of 0?3 mm. After the friction coefficient run-in, 230 data points were considered to calculate the average values.…”

“…Coatings were deposited using a METCO Diamond Jet HVOF gun with DJ 2701 air gap at a spray distance of 200 mm, powder spray rate of 60 g min 21 and air compressed flowrate of 304 L min 21 . These parameters were used for deposition of coatings with 0?3 mm of nominal thickness onto AISI 316L stainless steel substrates, with 173¡8 HV.…”

“…The abrasion resistance was verified in an instrumented rubber wheel abrasion test, following a modification of procedure 'E' of ASTM G65 standard. 20,21 The abrasive material employed was foundry sand with 99?8% silica content, with an average sand particle size of 0?3 mm. After the friction coefficient run-in, 230 data points were considered to calculate the average values.…”