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Production of Al_2TiO_5 sintered body with ultrafine microstructure.

超细微观结构Al_2TiO_5烧结体的制备

基本信息

批准号：
06650968
负责人：
KATO Akio
金额：
$ 1.47万
依托单位：
Kyushu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

项目摘要

(1)Al_2O_3 hydrate-coated TiO_2 particles were synthesized by homogeneous precipitation technique from Al_2 (SO_4) _3 solution in which TiO_2 fine particles in 20-40 nm diameter were suspended and their sinterability was studied. The composite powder gave a sintered body with 96% of theoretical density and 100% Al_2TiO_5 phase by sintering at 1500ﾟC for 4h. The sintered body consisted of grains above 10 mum. In addition of Y_2O_3, a sintered body with 92% T.D.could be obtained by sintering at 1400ﾟC,but, the grains grew into the large size of about 8 mum.(2)Al_2TiO_5 powder prepared by coprecipitation from sulfate (Al_2 (SO_4) _3, TiOSO_4) solution was sintered and the effect of additives on the microstructure of the sintered body was investigated. The addition of BaO,ZrO_2 or ZrSiO_4 was very effective for suppression of grain growth.In the case of no additive, Al_2TiO_5 sintered at 1300ﾟC consisted of grains of about 10 mum, and large cracks existed at the grain boundaries. In addition of 10mol%BaO or 5mol%ZrO_2, the dense sintered body (above 90%) having a microstructure consisted of grains of about 1 mum could be obtained, and no crack existed in a sintered body. BaAl_2O_4 phase or ZrTiO_4 phase formed in the sintered body is thought to suppress grain growth of Al_2TiO_5. Thermal expansion coefficients of sintered bodies added with BaO or ZrO_2 were larger a little, and their hysteresis became smaller than no additive. BaO and ZrO_2 suppressed a decomposition of Al_2TiO_5 to alpha-Al_2O_3 and TiO_2 (rutile).In Al_2TiO_5-ZrSiO_4 system, a composite sintered body having a microstructure could be obtained by sintering at 1400ﾟC in the component of Al_2TiO_580mol%-ZrSiO_420mol%. A thermal expansion coefficient of the specimen was almost the same as that of no additive. The specimen did not decompose by heating at 1100ﾟC for 8h.

(1)Al以粒径为20-40 nm的TiO_2微粒悬浮于Al_2（SO_4）_3溶液中，采用均匀沉淀法制备了水合二氧化钛包覆的TiO_2微粒，并对其烧结性能进行了研究。复合粉末在1500 ℃烧结4 h，烧结体的理论密度达到96%，Al_2TiO_5相含量为100%。烧结体由10 μ m以上的晶粒组成。添加Y_2O_3后，在1400 ℃烧结可获得92% T.D.的烧结体，但晶粒长大到约8 μ m的大尺寸。(2)Al以硫酸盐（Al_2（SO_4）_3，TiOSO_4）溶液为原料，采用共沉淀法制备了TiO_2TiO_5粉体，研究了添加剂对烧结体显微结构的影响。在无添加剂的情况下，1300 ℃烧结的Al_2TiO_5由约10 μ m的晶粒组成，晶界处存在大的裂纹。添加10mol%BaO或5mol%ZrO_2，可获得显微组织由约1 μ m的晶粒组成的致密烧结体（90%以上），且烧结体中不存在裂纹。认为在烧结体中形成的BaAl_2O_4相或ZrTiO_4相抑制了Al_2TiO_5的晶粒生长。添加BaO或ZrO_2的烧结体的热膨胀系数比未添加的烧结体稍大，滞后现象变小。在Al_2TiO_5-ZrSiO_4系统中，当Al_2TiO_580mol%-ZrSiO_420mol%组成时，在1400 ℃烧结可得到具有显微结构的复合烧结体。试样的热膨胀系数与无添加剂的试样的热膨胀系数几乎相同。试样在1100 ℃加热8h后不分解。