α-Si_3N_4与γ-Si_3N_4、α-Si_3N_4混合粉体超高压烧结的比较研究  

Compare Research on Ultra-High Pressure Sintering of α-Si_3N_4 with Mixed Powder of γ-Si_3N_4 and α-Si3N4

作　　者：姚怀[1] 徐巧玉[2] 苌清华[1] 刘海洋[1] 

机构地区：[1]河南科技大学材料科学与工程学院,洛阳471003 [2]河南科技大学机电工程学院,洛阳471003

出　　处：《山东陶瓷》2008年第6期16-20,共5页Shandong Ceramics

基　　金：国家自然科学基金(50472102)

摘　　要：以Y2O3-Al2O3-La2O3体系作烧结助剂,在5.4~5.7GPa、1620K^1770K的高温高压条件下进行了α-Si3N4与γ-Si3N4、α-Si3N4粉体的烧结研究。探讨了烧结温度及压力对烧结体性能的影响。实验测试结果表明:α-Si3N4、γ-Si3N4完全相变为β-Si3N4,相同的烧结条件下,α-Si3N4比γ-Si3N4、α-Si3N4混合粉体烧结试样的相对密度、维氏硬度高。α-Si3N4与γ-Si3N4、α-Si3N4混合粉体烧结试样的最高相对密度与维氏硬度分别为98.78%、21.87GPa和98.71%、21.76GPa。烧结体由相互交错的长柱状β-Si3N4晶粒组成,显微结构均匀。Ultrahigh pressure sintering of α--Si3 N4 and mixtures of α--Si3 N4 and γ- Si3N4 with Y2 O3 - Al2O3--La2O3 as additives were studied under pressures of 5.4--5..7 GPa and temperatures of 1570 --1770 K. The effects of sintering temperatures and pressures on properties of sintered ceramic samples were investigated. The results show that γ- Si3N4 and α--Si3 N4 is transformed to β - Si3 N, completely. The relative densities and Vickers hardness （Hv） of sintered samples from α--Si3 N4 are larger than those from the mixtures of γ- Si3N4 and α--Si3 N4 , under the same conditions. The highest relative densities and Vickers hardness （Hv） of the sintered compacts are 98.78%,21.87 GPa and 98. 71% ,21.76 GPa to pure α--Si3 N4 and those form the mixtures of T--Si3N4 and α--Si3 N4 , respectively. The sintered samples were composed of elongated β- Si3N4 rod crystals with disordered orientation and had an uniform microstrueture .

关 键 词：超高压烧结 相变 力学性能 显微结构 

分 类 号：TF124.5[冶金工程—粉末冶金]