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ZrB2-Cu composite is a new electrical contact materials in the integration of high conductivity, high wear resistance and good mechanical strength. In this paper, ZrB2-Cu composites were prepared by hot-pressing sintering at 800~900 °C under a pressure of 20 MPa.The densification of ZrB2-Cu composites was improved by the addition of nickel using an electroless metal plating technique. X-ray diffraction and scan electron microscopy were used to analyze the phase and microstructure of ZrB2-Cu composites. The results showed that ZrB2-Cu composites with 60 vol % Cu which was sintered at 900 °C had a higher relative density, highest flexural strength of 381 MPa and higher hardness of 2.16 GPa(HV). ZrB2-Cu composites with 50 vol % Cu which was sintered at 900 °C had higher flexural strength of 297 MPa and the highest hardness of 2.66 GPa.

Porous silicon nitride (Si3N4) ceramics green were prepared by sol-gel and freeze drying processing. Al2O3 and MgO were selected as sintering additives. Porous Si3N4 ceramics were sintered at 1200~1300 °C. The porosity of porous Si3N4 ceramics reached 60~80%, the pore size of porous Si3N4 ceramics dried by freeze drying is less than 5μm. Two kinds of pores were formed, including open pores with pore size of 1~5μm and closed pores pore size with the nanometer level. The compression strength of porous Si3N4 ceramics was 15~25MPa. Thermal conductivity of porous Si3N4 ceramics was 0.08-0.1 W/m·K.

SiCw/3Y-ZrO2/A12O3 composites were prepared. The composite powders were prepared by a precursor method. Samples were conventionally sintered at 1500°C and 1580°C for 2h in air. The density, phases, microstructure, hardness of the SiCw/3Y-ZrO2/A12O3 composites were investigated. It was found that the relative density of the samples decreased as the increasing content of SiCw. The optimum mechanical properties may be obtained in the SiCw/3Y-ZrO2/A12O3 composites with 5 vol.% SiCw.