The specimens of silica fume - glass fiber were prepared using silica fume with d50 about 200 nm as main starting material,adding 20 mass% glass fiber with different lengths (3,6,9,12 mm,respectively) after heat treatment and acid treatment,mixing,compressing shaping,and firing at 350 ℃ for 2 h. The bulk density, cold crushing strength, change in dimensions on heating, and thermal conductivity were determined,and the microstructure was analyzed. Performance determination shows along with the increase of fiber length,the cold crushing strength and thermal conductivity of the specimens increase slightly while bulk density and change in dimensions on heating keep unchanged;the bulk density of specimens added by 12 mm length of glass fiber is 0.438 g · cm-3 and cold crushing strength reaches 1.74 MPa,and the thermal conductivity is 0.050,0.061 and 0.092 W · m-1 · K-1,respectively. Microstructure analysis shows 3 mm length of glass fibers dispersively distribute in the specimens,6 to 12 mm length of glass fibers appear different degrees of agglomeration in the specimens,and there are big pores in the agglomeration of 12 mm length of glass fibers.%以d50≈200 nm的硅灰为主要原料,掺加20％(w)经过热处理和酸处理的不同长度(分别为3、6、9、12mm)的玻璃纤维,经混练、压制成型、350℃保温2h热处理后,检测烧后硅灰-玻璃纤维试样的体积密度、耐压强度、重烧线变化率、热导率,并分析试样的显微结构.性能检测发现:随着纤维长度的增加,烧后试样的耐压强度和热导率略有增大,体积密度和重烧线变化率几乎保持不变;掺加长度为12 mm的玻璃纤维的试样烧后的体积密度为0.438 g· cm-3,常温耐压强度达到1.74 MPa,在300、500、900℃的热导率分别为0.050、0.061、0.092 W·m-1·K-1.显微结构分析发现:长度为3 mm的玻璃纤维在试样中呈弥散分布;而长度为6、9、12 mm的玻璃纤维在试样中均出现不同程度的团聚,且长度为12 mm的纤维的团聚体内部存在较大的孔隙.
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