Ti3SiC2의 고온산화거동

Abstract

Ti3SiC2 material was synthesized via the powder metallurgical route, and oxidation tested between 900 and 1200oC in air for up to 100 hr. The oxidation of Ti3SiC2 material resulted in the formation of TiO2 and SiO2, accompanying the evolution of CO or CO2 gases from the initial stage of oxidation. The oxidation resistance of Ti3SiC2 mainly owes the protectiveness of highly stoichiometric SiO2. During the initial stage of oxidation, the dominant reaction was the inward transport of oxygen into the matrix. As the oxidation progressed, an outer TiO2 layer and an inner (TiO2+SiO2) mixed layer formed. Between these layers and inside the oxide scale, numerous fine voids formed. Numerous, fine oxide grains formed at 900oC developed into the outer coarse TiO2 grains and an inner fine (TiO2+SiO2) mixed grains at the higher temperatures. The oxidation resistance of Ti3SiC2 progressively deteriorated as the oxidation temperature increased, forming thick scales above 1000oC. The outer coarse TiO2 grains formed above 1100oC grew rapidly mainly along (211).