Polycrystalline diamond layers were deposited onto the titanium alloy Ti-6A
l-4V via microwave plasma chemical vapor deposition (CVD). It is shown that
the diamond film reduces wear and friction immensely compared with uncoate
d titanium/titanium tribe systems. An additional polishing process of the C
VD-diamond layer improves the wear behavior even further. An influence of a
ir humidity is found.
In addition, different ceramic materials (Al2O3, SiC, Si3N4, ZrO2) were tes
ted against as-deposited and polished CVD-diamond layers. Al2O3 and Si3N4 e
xhibit very good wear behavior accompanied by very low friction against as-
deposited CVD-diamond. SiC and ZrO2, however, show somewhat inferior wear a
nd friction behavior. Suggestions are made to explain the different perform
ance. Again, a wear increase is found with increasing humidity. Polishing o
f CVD-diamond layers improves the tribological performance further. (C) 199
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