凝胶注模法制备CA_(6)多孔陶瓷工艺的研究

Preparation of CA_(6) porous ceramics by gel-casting

以α-Al_(2)O_(3)微粉、CaCO_(3)(分析纯)为主要原料,以去离子水为溶剂,丙烯酰胺为单体,N,N’-亚甲基双丙烯酰胺为交联剂,采用凝胶注模工艺合成CA_(6)多孔陶瓷,研究了分散剂(NaPO_(3))_(6)加入量(分别占粉体质量的0、0.2%、0.4%、0.6%、0.8%和1%)、pH(pH分别为7、8、9、10、11、12和13)和固相含量(固相体积分数分别为40%、42%、44%、46%和48%)对α-Al_(2)O_(3)-CaCO_(3)复合浆料流变性以及CA_(6)多孔陶瓷性能的影响,从而确定凝胶注模法制备CA_(6)多孔陶瓷的最佳工艺。结果表明:随着α-Al_(2)O_(3)-CaCO_(3)复合浆料中(NaPO_(3))_(6)加入量的增加和pH的升高,其黏度呈现出先减小后增大的趋势;随着固相含量的增加,α-Al_(2)O_(3)-CaCO_(3)复合浆料的黏度逐渐增大,CA_(6)多孔陶瓷的体积密度随之增加,显气孔率随之降低。最佳工艺条件为:分散剂(NaPO_(3))_(6)加入量为0.4%(w),pH为11,固相含量为46%(φ),此时所制备的CA_(6)多孔陶瓷在保持高气孔率的同时具有较高的力学强度,且显微结构均匀性较好。

CA_(6) porous ceramics were synthesized by gel-casting usingα-Al_(2)O_(3) micropowder and CaCO_(3)(analytical pure)as main raw materials,deionized water as the solvent,acrylamide as the monomer and N,N’-methylene bisacrylamide as the crosslinking agent.Effects of the(NaPO_(3))_(6) addition(0,0.2%,0.4%,0.6%,0.8%,and 1%of the powder mass,by mass),the pH value(7,8,9,10,11,12,and 13)and the solid loading(40%,42%,44%,46%,and 48%,by volume)on the rheological properties of theα-Al_(2)O_(3)-CaCO_(3) composite slurries and the properties of CA_(6) porous ceramics were studied for the best preparation process of CA_(6) porous ceramics.The results show that with the increase of the(NaPO_(3))_(6) addition and the pH value of theα-Al_(2)O_(3)-CaCO_(3) composite slurries,the viscosity firstly decreases and then increases;with the increase of the solid loading in the slurries,the viscosity increases gradually,the apparent porosity of CA_(6) porous ceramics decreases,but the bulk density increases.The optimal conditions are the(NaPO_(3))_(6) addition of 0.4%,pH value of 11,and solid loading of 46%.The CA 6 ceramics prepared under these conditions have high mechanical strength and uniform microstructure.