CORROSION RESISTANT FLUORIDE BASED COMBINED CERAMICS SINTERED COMPACT

摘要

PROBLEM TO BE SOLVED: To obtain high strength (bending strength) without lowering excellent corrosion resistance peculiar to fluorides by forming a sintered compact which is obtained by combining a fluoride and alumina in a specified ratio. SOLUTION: The corrosion resistant fluoride based combined ceramics sintered compact is substantially composed of 70 to 85 wt.% of a fluoride and 30 to 15 wt.% alumina. It is preferable that the particles of alumina is dispersed in the fluoride and the particle sizes of the alumina are in the range of 0.1 to 0.3 μm. Though sinterable fluorides are used without any restriction as the main constituent phase of the fluorides constituting the sintered body, the preferable fluoride is at least one of CaF2, MgF2 and YF2. The preferable fluoride is constituted of a main constituent phase and a second constituent phase having a melting point lower than that of the main constituent phase. In this case, the second constituent phase mainly exists at the grain boundary of the main constituent phase and functions as a sintering aid to density the sintered body. LiF is preferably used as the second constituent phase.