Wear Behavior of Cold Pressed and Sintered Al(2)O(3)/TiC/CaF(2)-Al(2)O(3)/TiC Laminated Ceramic Composite

A novel laminated Al(2)O(3)/TiC/CaF(2)-Al(2)O(3)/TiC sandwich ceramic composite was fabricated through cold pressing and sintering to achieve better anti-wear performance, such as low friction coefficient and low wear rate. Al(2)O(3)/TiC/CaF(2) and Al(2)O(3)/TiC composites were alternatively built layer-by-layer to obtain a sandwich structure. Solid lubricant CaF(2) was added evenly into the Al(2)O(3)/TiC/CaF(2) layer to reduce the friction and wear. Al(2)O(3)/TiC ceramic was also cold pressed and sintered for comparison. Friction analysis of the two ceramics was then conducted via a wear-and-tear machine. Worn surface and surface compositions were examined by scanning electron microscopy and energy dispersion spectrum, respectively. Results showed that the laminated Al(2)O(3)/TiC/CaF(2)-Al(2)O(3)/TiC sandwich ceramic composite has lower friction coefficient and lower wear rate than those of AC/TiC ceramic alone because of the addition of CaF(2) into the laminated Al(2)O(3)/TiC/CaF(2)-Al(2)O(3)/TiC sandwich ceramic composite. Under the friction load, the tiny CaF(2) particles were scraped from the Al(2)O(3)/TiC/CaF(2) layer and spread on friction pairs before falling off into micropits. This process formed a smooth, self-lubricating film, which led to better anti-wear properties. Adhesive wear is the main wear mechanism of Al(2)O(3)/TiC/CaF(2) layer and abrasive wear is the main wear mechanism of Al(2)O(3)/TiC layer.