Titanium Carbide Ring And Chrome Carbide Liner Coatings

For evaluating wear couples used in low heat rejection engine tests, sample temperatures were set to 427°C and load maintained at 70 lbf/in. Figure 5 shows results for the titanium carbide ring on the chrome carbide liner without lubrication. This is combination 3 in Table 1. There was no progressive change in friction coefficient as test time progressed. The average value remained quite high at 0.58. Figure 6 shows a trace of the surface of the liner prior to testing (sampling interval 39 liin). The surface is relatively-rough. Figure 7 shows the surface after two hours in the Hohman-A9 tester. Very high wear is evident and some smoothing occurred. (sampling interval 281 uin).

The friction coefficient dropped significantly with time when, synthetic oil Type A was used. Figure 8. This is combination 5 in Table 1. After two hours the friction coefficient dropped to about 0.1. The test duration proved to be too short to obtain a resolvable amount of wear using the profilometer.

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