Method for cold sintering glass powder to achieve and / or maintain transparency, product produced by this method

Abstract

The glass powder is mixed with a solid inorganic flux, the components are ground together to achieve a particle size of up to 150 µm, then the material is compressed at a pressure of less than 600 MPa and heated in a mold to a temperature of less than 450 ºC, the material remains in the mold under these conditions for at least 15 minutes, and then cooled in the mold and / or outside the mold. The glass powder includes or consists of SiO2 or SiO2 + Al2O3. The flux is in an amount of up to 45 wt. %, preferably in the range of 5 wt. % to 25 %, particularly preferably in the range of 12 wt. % to 18 wt. % of the total weight of the mixture with the glass powder. The flux is Na2SiO3 and / or Na2SiO3 hydrate, and / or Na2O 2SiO2 2H2O, and / or Na3PO4, and / or Na3PO4 hydrate. The material in the mold remains at a temperature preferably in the range of 100 ºC to 350 ºC and at a pressure in the range of 50 MPa to 500 MPa, preferably up to 250 MPa. The residence time of the material in the mold at elevated temperature and under pressure is in the range of 20 min. to 120 min., preferably in the range of 30 min. to 90 min.

Images