共沉淀法制备Al(OH)_3-Y(OH)_3/ZrB_2复合粉体的热力学形成条件研究

Thermodynamics conditions of preparing Al(OH)_3-Y(OH)_3/ZrB_2 composite powder via the co-precipitation method

由于ZrB2的独特晶体结构,使其兼有金属和陶瓷的许多优异的物理和化学性能,因此在许多领域得到广泛应用。本文利用共沉淀法制备A1(OH)3-Y(OH)3/ZrB2复合粉体,并研究其形成热力学条件。经过热力学计算并用实验验证得出:ZrB2悬浮液的pH值必须大于8.3,才符合Al3+与Y3+共沉淀所需热力学条件;当ZrB2悬浮液的pH值为9时,A1(OH)3-Y(OH)3/ZrB2复合粉体的壳-核结构最好。在溶液浓度较低的情况下,可以获得具有理想壳-核结构的A1(OH)3-Y(OH)3/ZrB2复合粉体,即c(Al3+)=0.017mol/L,c(Y3+)=0.010mol/L,分别接近于Al(NO3)3和Y(NO3)3浓度的热力学条件计算拟定值,即:0.012 60mol/L和0.007 56mol/L。

Zirconium diboride is widely used because of some excellent properties of metal and ceramics. The thermodynamics of preparing A1 （OH）3-Y （OH）3/ZrB2 composite powder via the co-precipitation method were investigated. The results show that pH value of solution must be higher than 8.3 to meet the thermodynamics conditions needed for co-precipitation of A13 ＋ and y3 ＋. When the pH of ZrB2 suspension is 9, the shell-core structure of A1 （OH）3-Y（OH） 3/ZrB2 composite powder is the best. When the concentration of solution is lower, the shell-core structure of A1 （OH）3-Y（OH） 3/ZrB2 composite powder is better, that is c（ A13＋） = 0. 017mol/L and c （y3＋） = 0.010mol/L, which close to 0. 012 60mol/L and 0. 007 56mol/L calculated by the thermodynamics.