High silica fibers are high purity glass fibers containing more than 96% silicon dioxide produced by leaching method, which have good ablation resistance. When the content of silica reaches 99.95%, it belongs to the category of quartz fibers.
High silica fibers have high specific strength. The thermal properties of high silica fibers and quartz fibers are basically similar. The main difference is that the melt viscosity of quartz fibers is higher than that of high silica fibers. The reason is that quartz contains more silica. High silica and quartz do not melt or evaporate below 1650 C. When the temperature continuously exceeds 982 C, the two forms of silica begin to transform into crystalline form of cristobalite, which hardens the material, but does not cause changes in physical shape or insulation properties. High silicon oxygen has good thermal shock resistance. Its products can be heated to 1090 C and quenched in water without any obvious change. High silica products are not suitable for hot or cold alkali. In some applications, they can be used in weak alkali solution. High silica fibers are insoluble in organic solvents.