氧化铝源对CA_(6)多孔材料相组成和显微结构的影响

Influence of Alumina Source on Phase Composition and Microstructure of CA_(6) Porous Materials

用Al(OH)3、Al_(2)O_(3)微粉(uf-Al_(2)O_(3))、工业Al_(2)O_(3)粉作为氧化铝源,CaCO_(3)为钙源,通过高温固相反应合成了六铝酸钙(CA_(6))材料,研究了氧化铝原料对材料物相组成、显微结构和性能的影响。结果表明,以Al(OH)3、Al_(2)O_(3)微粉、工业Al_(2)O_(3)为氧化铝源的试样在1300℃时开始有CA_(6)相生成,各试样固相反应结束温度为1500℃,继续提高烧成温度对物相组成没有影响。反应生成的CA_(6)显微形貌因氧化铝原料不同而不同,以Al(OH)3为氧化铝源时,CA_(6)的显微形貌多为片状结构;以工业Al_(2)O_(3)为原料时,CA_(6)的显微形貌多为板片状和颗粒状;但以uf-Al_(2)O_(3)为氧化铝源时,CA_(6)的显微形貌则多为等轴状晶粒。以uf-Al_(2)O_(3)为氧化铝源时,制备的材料耐压强度和体积密度最高,气孔率最低;以Al(OH)3为氧化铝源时,制备的材料耐压强度和体积密度最低,气孔率最高。

CA_(6) materials have been synthesized by high temperature solid state reaction using CaCO_(3) as calcium source combined with Al(OH)3,uf-Al_(2)O_(3) and industrial Al_(2)O_(3) as alumina sources.Effects of alumina sources on phase composition,microstructure and properties of CA_(6) materials were studied.The results show that CA_(6) forms at 1300℃using Al(OH)3 and uf-Al_(2)O_(3) as alumina sources.Solid state reaction temperature of samples finishes at 1500℃.Further increasing of firing temperature has no effect on the phase composition.The microstructure of CA_(6) produced by the reaction is changed with different alumina sources.When Al(OH)3 is used as the alumia source,the microstructure of CA_(6) is mostly platy.However,as used industrial Al_(2)O_(3) as the alumia source,the microstructure of CA_(6) is mostly plate-like and granular,but the microstructure of CA_(6) is mostly equiaxed grains by using uf-Al_(2)O_(3) as precursor.When used uf-Al_(2)O_(3) as the source,the compressive strength and bulk density of the materials are the highest,and the porosity is the lowest.As used Al(OH)3 as alumina source,the compressive strength and bulk density of the materials are the lowest,and the porosity is the highest.