ADVANCED CERAMIC TOOLS FABRICATED FROM CERAMIC COATED CARBIDE POWDERS
An experimental investigation is carried out to coat two types of carbide powders, TiC and (W, Ti) C, with an alumina ceramic using a sol-gel technology. The coated carbide powders are then fabricated into two kinds of new ceramic tool materials by the hot pressing method. A scanning electron microscopy (SEM) observation reveals that the matrix (carbide) grains are uniformly coated with the alumina ceramic and the new tool materials have a homogeneous microstructure. The tests of mechanical properties and wear resistance in machining are finally conducted. It is shown that the new tool materials can increase the tool-life by up to 100% as compared to other ceramic tool materials when machining a mild carbon steel, while the fracture toughness is improved by up to 33%. When compared with a hard coated carbide tool, the new materials exhibit a superior ability in maintaining the wear resistance during the entire tool-life.