Synthesis of beta-SiAION Powder by Carbothermal Reduction-Nitridation of Zeolite

摘要

P-SiAION ceramics have high strength, high hardness, high oxidation and corrosion resistance. It has been fabricated by sintering of Si_3N_4-AlN-SiO_2-Al_2O_3 powder mixture or p-SiAlON powder. Many researchers have synthesized the P-SiAlON powder by carbothermal reduction-nitridation of SiO_2-Al_2O_3 system or minerals, such as clay. Zeolite is composed of Si, Al and 0, and has high specific surface area and very small pore. The purpose of this study is to fabricate beta-SiAION powder by carbothermal reduction-nitridation of zeolite. Y-type zeolite and carbon powders were mixed in ethanol for 60min. After the slurry was dried, the mixed powder was fired at 1000 to 1450 deg C for 0 to 120min in 0.5/lmin N_2 flow, followed by heat-treatment at the temperature of 700 deg C for 120min in air in order to remove residual carbon. As a result, it was confirmed that the main phase of synthesized powder fired at 1450 deg C for 120min was P-SiAlON and the powder was composed of ultra fine particles with 25m~2/g of BET surface area and 70nm of mean particle size. Consequently, zeolite was concluded to be very useful raw material to synthesis very fine P-SiAlON powder.