以煅烧氧化铝粉、柠檬酸铵、十二烷基硫酸三乙醇胺、丙烯酰胺、N,N’-亚甲基双丙烯酰胺、过硫酸铵、N,N,N’,N’-四甲基乙二胺、硅溶胶、氯化铵、铝酸钙水泥、聚丙烯酰胺为原料,采用发泡法造孔原理,分别结合凝胶注模工艺、溶胶凝胶工艺和水泥固化工艺三种不同的固化成型方法,制备了新型Al2 O3基多孔陶瓷隔热材料。结果表明:三种方法所制备试样的烧后收缩率在11.5%~12.8%,体积密度在0.70~0.75 g·cm^-3,显气孔率在80.2%~82.0%,差别较小;凝胶注模工艺制备的多孔陶瓷为纯相的α-Al2 O3,溶胶凝胶工艺制备的多孔陶瓷还有少量莫来石,水泥固化工艺制备的多孔陶瓷还有少量六铝酸钙相;三种方法制备的多孔陶瓷的结构非常相似,都为明显的球形孔结构,且其耐压强度和热导率差别也不大,但耐压强度比目前高温隔热常用的Al2 O3多晶纤维板明显要高,热导率与Al2 O3多晶纤维板的相近。
New type heat insulation materials of alumina based porous ceramics were prepared via foaming method as pore-forming mechanism combined with gel-casting,sol-gel or cement curing process,using calcined alumina powder,ammonium citrate,triethanolamine lauryl sulfate,acrylamide,N,N’-methylenebi-sacrylamide,ammonium persulfate,N,N,N’,N’-tetramethylethylenediamine,silica sol,ammonium chlo-ride,calcium aluminate cement,polyacrylamide as starting materials.The results show that the properties differences of the prepared specimens by the three methods are small:shrinkage after firing is between 1 1 .5%-12.8%,bulk density is between 0.70 -0.75 g · cm^-3 ,apparent porosity is between 80.2% -82.0%;porous ceramics prepared by gel-casting only contain pure α-Al2 O3 phase,those by sol-gel con-tain a small amount of mullite besides α-Al2O3,and those by cement curing contain a small amount of hexaluminate besides α-Al2 O3;the ceramics have similar structures with obvious spheric pores,compres-sive strength and thermal conductivity.Compared with the current heat insulation polycrystalline alumina fi-ber sheet,they have higher compressive strength and similar thermal conductivity.