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Synthesis of Spinel Powder by the Homogeneous Precipitation Method from Inorganic Salts and Their Sintering.

无机盐均相沉淀法合成尖晶石粉及其烧结。

基本信息

批准号：
01550604
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：
1989
资助国家：
日本
起止时间：
1989 至 1990
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-01550604/
关键词：
Homogeneous precipitation method Inorganic salts Spinel Alumina Urea スピネル(MgAl_2O_4)アルミナ(Al_2O_3)

项目摘要

Spinel (MgAl_2O_4) powders were prepared by the homogeneous precipitation method from the aqueous solutions of nitrates or sulfates mixture of aluminum and magnesium using urea, and their sinterability was studied.Precipitates with spinel composition obtained from the nitrate solution consisted of Al_2O_3 gel and Mg-Al double hydroxide. From the sulfate solution. MgO hydrate deposited on Al_2O_3 hydrate particles. On heating above 800^ﾟC for 1h in air, both precipitates became spinel phase. Indicating the higher reactivity of both components in the present powders than that in the powder mixture of MgO and Al_2O_3.The powder prepared from the solution of nitrates mixture became solid coagulation on drying. When powder ground and calcined at 800^ﾟC was sintered at 1500^ﾟC for 4h, a sintered body with 95% of theoretical density was obtained. In sintering at 1600^ﾟC, the same density was obtained.On the other hand, in the powder prepared from the solution of sulfates mixture, a sintered body with 96.7% of theoretical density was obtained when the synthesized powder was calcined at 1000^ﾟC and sintered at 1500^ﾟC for 4h. A sintered body with 99.2% of theoretical density was obtained by sintering at 1600^ﾟC for 4h from the powder calcined at 800^ﾟC and ground.As a fundamental study on synthesis of spinel powder, the effect of synthesis conditions, especially the effect of additives, on the morphology of Al_2O_3 hydrate was investigated in the precipitation from aluminum salt solution by the homogeneous precipitation using urea.

用尿素均匀沉淀法从铝镁混合物的硝酸盐或硫酸盐水溶液中制备了尖晶石（MgAl_2O_4）粉体，并研究了其烧结性能。从硫酸盐溶液中分离出来。MgO水合物沉积在Al_2O_3水合物颗粒上。在空气中加热到800 ℃以上1h时，两种沉淀物都变成尖晶石相.结果表明，硝酸盐混合溶液制得的粉体在干燥过程中呈固体凝聚状态，其反应活性高于MgO和Al_2O_3的混合粉体。将研磨后的粉末在800 ° C下煅烧，在1500 ° C下烧结4h，得到理论密度95%的烧结体。在1600 ° C烧结时，烧结体的密度与烧结体的密度相同，而在硫酸盐混合溶液中制备的粉末，在1000 ° C煅烧，在1500 ° C烧结4h，烧结体的密度达到理论密度的96.7%。将800 ℃煅烧后的粉体粉碎，在1600 ℃下烧结4h，可得到理论密度为99.2%的烧结体。研究了尿素均相沉淀法从铝盐溶液中沉淀Al_2O_3水合物的形貌。