The Solid Phase Sintering Of Silicon Carbide Ceramic And Preparation Of Grinding Media Ball

Silicon carbide ceramics with its excellent properties is widely used in national defense, machinery, metallurgy, electronics and other industry fields. In many ceramics materials, Si C has been hot discussed in the study of material science for its high hardness, anti-high-temperature oxidation, good stability, low expansion coefficient and good heat conduction.Compact Si C ceramic was prepared by solid phase sintering process parameters(pressureless sintering process and hot-pressing sintering process) in this paper.The influence of the sintering preservation time, sintering temperature and the hot-pressing pressure on the performance of the ceramic were mainly discussed. And its microstructure and properties were charactered and tested with Hydrostatic balance,universe tester,microhardness tester, SEM and XRD. The results show that, the optimal processing parameters of pressureless sintering were determined at 2010℃×45 min and in this condition, the ceramic volume density, bending strength and fracture toughness were up to 3.1261g/cm3, 4.46 MPam1/2 and 379 MPa, respectively. The optimal processing parameters of hot-pressing sintering were determined at 1900℃×60min×50MPa and in this condition, the ceramic volume density fracture toughness and bending strength were up to 3.1756g/cm3 and 5.12 MPam1/2 and 596 MPa, respectively.This paper is based on the results of the predecessors which use the same particle size(1μm) β-Si C and α-Si C particles as experimental materials. The result shows that the optimum adding amount of the β-Si C within pressureless sintering and hot pressing sintering ceramic were 5% and 10% respectively. And the sintered β-Si C grain was long cylindrical and the fracture toughness had greatly improved by the addition of β-Si C addition. Compared with the ceramic sintered by pure α-Si C, the fracture toughness of ceramic sintered by pressureless increased to 0.52MPam1/2 and the hot-pressing sintering process increased to 0.21 MPam1/2, respectively. The bending strength of pressureless sintering ceramic increased from 341 MPa to 379 MPa, and the bending strength of the hot-pressing sintering ceramic increased from 527 MPa to 596 MPa.The production process of grinding media ball was studied. The results showed that the Rolled molding(Rolling mold and Cold isostatic pressing mold) had an effect on the density of ceramic ball apparently. Rolled forming ceramic ball sintering density was 2.93g/cm3 and all ceramic ball’s crushing value was less than 2.08% when the grinding ball diameter was 1mm, 2mm, 3mm, 4mm and 5mm under the pressure of 36.8MPa, 32.1MPa, 29.9MPa, 16.1MPa and 13.8MPa, respectively. The abrasive wear resistance rate was all less than 0.95g/kg·h when the diameter of the grinding ball was from 1mm to 5mm ball and the lowest wear resistance rate(0.27g/kg·h) was obtained when the diameter is 3mm. Paraffin as a sealing material was used for coating green body ball and the sintering density increased to 2.958g/cm~3.