Manfred Sulik

The Glass Related Properties of the SIBOR® Oxidation Protective Coating on Molybdenum Alloys

The SIBOR® (Si-10B-2C) oxidation protective coating was applied onto molybdenumand molybdenum – 3 wt% zirconia samples by APS (= Atmospheric Plasma Spraying) with a subsequent heat treatment. Then the coated samples were submitted to ramp oxidation tests with heating rates of 10°C / hour up to a temperature of 1450°C. This procedure simulates the heating up of a glass melting tank where SIBOR® coated parts are most frequently used. Some of the samples which could be oxidized without any defect were then immersed in various molten glasses to determine the dissolution rate of the SIBOR® substrate system. This simulates the situation when the glass melting tank is filled and operated with molten glass. SIBOR® proved to be an excellent oxidation protective coating for the molybdenum – zirconia – material like for pure molybdenum. The coating was fairly good dissolved by opal glass and – slightly less – by soda lime glass. With borosilicate glass a much slower interaction was found. In all cases some discolouration and bubbles were found in the glasses after one week.