Reactive process in interface between TiO₂ and O'-Sialon

TiO₂/O'-Sialon diffusion couple was designed and prepared with reactive sintered O'-Sialon and rutile TiO₂ as raw materials. The phases of interface and cross-section phases were determined by XRD and morphology and element section distribution were analyzed by SEM and EPMA. On the base of information obtained above, the reactive process in the interface of TiO₂/O'-Sialon diffusion couple was discussed. The results of XRD show that TiO₂ reacts with O'-Sialon in the interface, which produces TiN and SiO₂, but the degree of the reaction is weak at 1200°C, gravity segregation of Sm₂O₃ is found and Sm₂Si₂O₇ is generated by Sm₂O₃ and SiO₂ in the interface; and irregular fusion zone is observed in the interface through SEM; the analysis of element distribution by EPMA states that element Si and Ti enrich in the zone but there is only micro-element diffusion to the base. The conclusion is obtained by analysis mentioned that the reactive process can be divided into three stages: physical contact, formation of fusion zone and element-enrichment, growth of fusion zone.