| 摘要 |
PURPOSE:To produce chemical-resistant porous glass having a large pore volume, by properly heat-treating a melt formed article of a specific composition consisting of SiO2, B2O3, alkaline earth metal oxide, ZrO2, Na2O and Al2O3 and washing the resultant heat-treated material. CONSTITUTION:A raw material composition consisting of 40-75wt% SiO2, 15-40wt% B2O3, 5-30wt% alkaline earth metal oxide, 4-20wt% ZrO2, 0-20wt% Na2O and 0-5wt% Al2O3 is melt formed at a temperature within the range of about 1,200-1,500 deg.C. The above-mentioned melt formed article is then heat-treated at a temperature within the range of 500-800 deg.C for about 2-100hr to form a structure constituted of a phase consisting essentially of SiO2 and ZrO2 and phase consisting of other oxides consisting essentially of B2O3. The resultant formed article is then dipped in an acid to elute the latter phase and the article is further washed to remove gelatinous materials in pores. Thereby the aimed porous glass having resistance to chemicals, e.g. alkalis, acids, etc., and large pore volume without containing the residual gelatinous materials in the pores is readily obtained by using the normally used raw materials.
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