To make a further understanding of the materials removal mechanisms of polycrystalline sintered silicon carbide (SiC) ceramics

a single diamond grain scratch platform was built to carry a single diamond grain scratch test on the polycrystalline solid phase sintered silicon carbide ceramics. In the scratching process

the chip formations were observed and the scratching force signals were collected and analyzed

then the scratch morphologies were observed with an optical microscope.The results show that the chip forms of sintered SiC ceramics are classified into continuous chips and collapsing chips

and scratching process has in turn experienced continuous chips formation stage

continuous chips accumulation stage and chips collapsing stage. Besides

when the scratching speed v=0.01mm/s

there is a significant turning point of tangential and normal scratch force at the time of 16s. Whereas

at the scratching speed of 0.04mm/s

the turning point just appears in normal scratching force

and the normal grinding force fluctuates heavily when the scratching time exceeds 12.5s

which may be due to the collapsing chips formation. What’s more

even the SiC ceramic materials are removed in ductile mode

there are fishscales cracks appearing on the scratching surface. When polycrystalline SiC ceramics removed in brittle mode

the fractured surfaces transforms from the discontinuous region into the continuous region with the increasing scratching depth. Eventually

the fractured surface extends to the non-scratching area.