The application of PIM (powder injection molding) process of cemented carbide parts bas been studied. Two kinds of cemented carbide powders, with the particle size of 3um and 0.4um respectively, were used in the experiments. Two kinds of binders were applied. The rheological properties of feedstocks were studied. The thermogravimetry analysis and thermal debinding cycles were investigated. Possible defects introduced in PIM process steps were described. The influences of holding temperature and holding time during debinding on the carbon content in compacts were studied. The mechanical properties of cemented carbide parts prepared with different partiele sized powders were compared.

Ti'/AI203 Functionally Gradient Material (FGM) was prepared by an explosive compaction/SHS process. Ten sheets of the compounding powder were laminated and pressed to get a green body of FGM. It was then compacted explosively. By burying the explosive compaction body into a stoichiometric AI/TiO2 mixture and igniting the combustion of the stoichiometric AI/TiO2 mixture, the SHS reaction of the explosive compaction body was initiated by the heat released from the combustion of the stoichiometric AI/TiO2 mixture. In this way, Ti/AI203 FGM was synthesized. The adiabatic temperatures of each gradient layer were calculated when the pre-heating temperatures were 298 K and 1173 K, respectively. The microstructure, composition and properties of Ti/AI203 FGM and the reaction mechanism of each gradient layer were studied. It was found that Ti/AI203 FGM prepared by the explosive cornpaction/SHS process had a high density and a high microhardness. Its structure, composition and properties showed apparent gradient distribution. The structure of the standard stoichiometric ratio gradient layer of FGM was a network structure. Its reaction mode could be described as follows: AI powder melted first, then the molten AI penetrated into the TiO2 zone and reacted with TiO2, and big pores were left in the original positions of AI powder. The reaction of gradient layers with the addition of AI203 as diluents was similar to that of the standard stoichiometric ratio gradient layer, so were their structure and composition. However, the reaction of gradient layers with the addition of Ti as diluents was more complex and the composition deviated slightly from the designed one.