Corrosion Resistance of Ceramics and High-temperature Phase Change of Powders on Cubic Silicon Nitride
An installation, consisting of an explosive-driven planar flyer and a cylindrical chamber, was designed to synthesizeγ-Si3N4 with cubic spinel structure using the mixtures of impure α -Si3N4 and copper powders as starting materials. Sintering ofγ-Si3N4 with Y2O3-Al2O3-La2O3 as additives were studied under pressures of 5.7 GPa and temperatures of 1370K. The corrosion resistance ofγ-Si3N4 sintered compact to hydrofluoric acid was investigated at temperature between 490K and 500K, and its thermal stability ofγ-Si3N4 powder prepared by shock wave synthesis was studied at temperature between 1670K and 1690K in a nitrogen atmosphere. The results show thatγ-Si3N4 sintered compact could not react with hydrofluoric acid at 490K. At 500K,γ-Si3N4 sintered compact could reaction with hydrofluoric acid slowly, and 0.2gγ-Si3N4 sintered compact quality reduced 0.013g after 6h. Theγ-Si3N4 sintered compact could not react with hydrochloric acid, nitric acid, sulfuric acid and universal solvent at 500K. Theγ-Si3N4 powder was quite stable and without phase transformation at 1670K, and after soaking at 1680K for 10 min and 30 min, the ratio of transformation fromγ-Si3N4 to β -Si3N4 is about 0% and 80%, respectively. Theγ-Si3N4 powder could be completely transformed into β -Si3N4 after soaking at 1690K for 30 min.
YAO Huai XU Qiaoyu CHANG Qinghua
School of Materials Science and Engineering, Henan University of Science and Technology,Luoyang 4710 School of Electromechnical Engineering, Henan University of Science and Technology, luoyang 471003, School of Materials Science and Engineering, Henan University of Science and Technology, Luoyang 471
国际会议
桂林
英文
1-5
2010-11-16（万方平台首次上网日期，不代表论文的发表时间）