稀土氧化物对TiB_2陶瓷致密化程度的影响(英文)

1 IntroductionThe merits of TiB_2 ceramics:high hardness,high melting point,chemical stability athigh temperature,wear-resisting,corrosion-resisting and good heat-conduction lead itto have various latent usages in chemical engineering, electro-engineering and otherhigh techs.But its applications are seriously limited due to the fact that it is easy togrow into coarse grains during sintering and difficult to obtain high dense TiB_2 prod-ucts.It is,therefore,necessary to find some effective additives as the second aid.This work has approached the densification process by adding rare earth oxides Y_2O_3,La_2O_3 and CeO_2.

热压Al_2O_3-ZrO_2(6mol%Y_2O_3)陶瓷复合材料的组织性能研究

本文考察了全稳定ZrO_2对Al_2O_3陶瓷的组织性能的影响.结果表明,热压Al_2O_3-ZrO_2(6mol%Y_2O_3)陶瓷材料的显微形貌与其它Al_3O_3-ZrO_2陶瓷的几乎完全一样,小量C—ZrO_2的存在可促进Al_2O_3陶瓷的烧结并细化晶粒,从而提高材料的力学性能,但其增韧增强能力有限.大量c-ZrO_2的存在因其本身低的力学性能、缺乏相变韧化和存在残余拉应力而使材料的力学性能下降.

Y－TZP强化Al_2O_3超细材料的组织性能研究

制备了纳米级Ｙ－ＴＺＰ（Ｙ＿２Ｏ＿３稳定的四方ＺｒＯ＿２多晶）强化Ａｌ＿２Ｏ＿３陶瓷复合材料，并研究了其组织性能。发现纳米粉末有利于提高制品的密度和获得细晶组织。有两种ＺｒＯ＿２粒子存在于该复合材料中，即Ａｌ＿２Ｏ＿３晶内的十分细小的ＺｒＯ＿２粒子和镶嵌于Ａｌ＿２Ｏ＿３晶界的ＺｒＯ＿２粒子，这两种粒子共同作用，十分显著地提高制品的强度，后者还有利于高温性能的改善。２０（ｖｏｌ）％（Ｙ－ＴＺＰ）－Ａｌ＿２Ｏ＿３纳米复合材料的抗弯强度和断裂韧性分别达到１７５０ＭＰａ和６．１ＭＰａ．ｍ￣（１／２）。断裂韧性的缓慢提高主要是由于制品的高密度及晶粒细化的结果。