Method of melting glass in a platinum container in a controlled atmosphere

Abstract

Abstract This invention provides methods for melting glass laser compositions to provide glass laser rods with a minimum of noble metal inclusions and a minimum of dissolved noble metal content. The process comprises melting the laser glass in a platinum container in a controlled reducing atmosphere using a buffered gas mixture, such as CO2/CO in which the partial pressure of oxygen is at a minimum level that is equivalent to a range of about 10 8.6 to 10 38 atmospheres for a temperature range of about 981*F. to 3,321*F. for a silicate glass. A method also is provided for melting glass to make high-quality glass articles in a noble metal container or a lined container in which the container or the liner therefore has at least 50% by weight of platinum without any attack on the container by the unwanted formation of a noble metal alloy from the glass melt during melting. The method comprises heating molten glass in the platinum container, providing a reducing atmosphere in which the partial pressure of oxygen is no greater than about 10 3 atmospheres with a buffered gas mixture, and controlling the reducing atmosphere by maintaining the partial pressure of oxygen above the amount at which oxides of an element such as SiO2, Li2O and Na2O are reduced to the element such as Si, Li or Na, so that the element does not react with the platinum metal to form a platinum-Si alloy.

Inventors

• 👤 Earl D Dietz
• 👤 Paul R Wengert

Bibliographic Details