Research in the Area of Preparing Materials Based on Fuzed Quartz HCBS. Part 9. Effect of Alkali Additions on Material Cristobalitization and Thermal Expansion After Nonisothermal Heating1

Resumo

The effect of alkali-containing additive of water soluble lump silicate on the degree of cristobalitization and thermal expansion of specimens based on fuzed quartz HCBS is studied. The additive content (for Na₂0) is varied within the limits of 0.1 – 2.0% or from 0.025 to 0.50%. In specimens given prior nonisothermal heating to 1500°C the cristobalite content is from 32 – 34% (specimens without additive) to 88 and 96% (specimens with 1 and 2% additive). Specimen maximum thermal expansion corresponding to transition of low-temperature into high-temperature cristobalite occurs within a limited range of 150 – 300°C.