高温アンモニア・水混合液による摺動材料の腐食試験

概要

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To investigate the shaft seal for NH_3-H_2O binary vapor turbines, first of all, immersion tests of several sliding materials were carried out in a static NH_3-H_2O mixture (NH_3 concentration: 30 wt%) for 100 h under the condition of maximum temperature at 450℃. The test materials were selected from the sliding materials commonly used as mechanical seal rings, such as SiC ceramics, Al_2O_3 ceramics, hard metals and carbon materials. (1) SiC specimens prepared with B (boron) and C (carbon) as sintering additives under the pressureless sintering process were confirmed to be most preferable. On the other hand, pressureless sintered SiC with Al_2O_3 additive and reaction bonded SiC indicated worse anti-corrosive resistivity. The Al_2O_3 additive in the pressureless sintered SiC and the excess metallic Si in the reaction bonded SiC were the most corrosive parts in the structure of SiC ceramics. (2) Al_2O_3 were recognized as anti-corrosive materials. (3) Hard metals were corroded easily. (4) The resin was corroded selectively in resin impregnated carbon material. Non-impregnated carbon material was hardly corroded. (5) These materials, with better anti-corrosive properties, can be used for the mechanical seal of NH_3-H_2O binary vapor turbines, although the increase in the surface roughness and the reduction of the bending strength were observed slightly.
社団法人日本セラミックス協会の論文
1992-12-01