Volume 4, Issue 10 (November 2007)
Friction and Wear Behavior of Electroplated and Thermal Sprayed Coatings Tested in an Instrumented Rubber Wheel Abrasion Test
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.