Abstract
This paper reports certain initial studies wherein unstressed selected high temperature alloys, representing four main classes by composition, were exposed to molten boron oxide. Test conditions ranged from 1600 to 2000 F in air and inert atmospheres for time periods of about 150 hours. A special, high temperature furnace operating under reproducible and closely controlled conditions, alternately cycled the specimens between the molten boron oxide liquid and gas atmosphere environments. Results showed that molten boron oxide is very corrosive, particularly to iron and cobalt base alloys at temperatures over 1800 F. Some alloy constituents as carbon, aluminum, titanium and iron at low concentration levels appear to reduce alloy resistance to molten boron oxide. Mechanical strength data showed that the alloy's plastic properties are more rapidly affected than the elastic properties. The effect of atmosphere, temperature, alloy composition and other factors are evaluated. Several mechanisms of corrosive attack by molten boron oxide are postulated to explain the data. 4.7