| 摘要 |
PROBLEM TO BE SOLVED: To suppress transformation from a T-phase of a zirconia to a M-phase, and prevent abrasion of a counterpart member by forming a part of a sliding member serving the zirconia as a main body, and forming a vane of ceramic sintered body in which magnesia is added as a stabilizing agent. SOLUTION: A vane 3 is formed of ceramic sintered body in which magnesia is added as stabilizing agent serving a zirconia as a main body. The sintered body is constituted by the magnesia of 1 to 30 wt.% and the residual part which consists of the zirconia, and its average particle diameter is set to 3μm and less. The roller 2 is made of alloy casting iron including at least one of metal materials of Ni, Cr, Mo, and W, and its Rockwell hardness HRC is set to 48 to 56. It is thus possible to prevent generation of cracking caused by volume expansion in association with transformation from a tetragonal T-phase to a monoclinic M-phase of the zirconia by a sliding operation in a high temperature region. Iron chloride is not formed in hydrocarbon fluoride coolant, a metal contact condition is increased, the hardness of the sintered body is reduced by adding of the magnesia, and abrasion of the roller 2 is reduced.
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