Hitachi, Ltd.

Osamu Nishida

Yuichi Ishikawa

Nobuyoshi Hosaka

Tetsuo Nakazawa

Masakatsu Sakamoto

Shigeru Shida

Occurence of crevice corrosion on metal surfaces in crevices is prevented by providing an anti-crevice corrosion sealant which comprises a rubbery substrate containing 5-350% by weight of fine zinc powder, 20-100% by weight of magnesium oxide, and 20-200% by weight of electrostatically charged fine graphite powder, each on the basis of the rubbery substrate, in the crevices between parts of stainless steel articles or aluminum alloy articles.

Anti-crevice corrosion sealant and method for anti-crevice corrosion

To prevent erosion-corrosion of capsules moving by means of a fluid through a pipe line, straight chain, macromolecular materials are deposited on the surfaces of capsules before introduction into the pipe line, a corrosion inhibitor is added to the fluid, and said corrosion inhibitor of higher concentration is deposited to the capsules before a temporary exposure to the atmosphere.

Method for preventing erosion-corrosion of hydraulic capsule

A process for regulating the hardening speed of a self-hardening mold which comprises adding an alcohol as a hardening speed regulating agent when a mold is formed with molding sand prepared by adding a polyvinyl alcohol solution and a boron compound to refractory particles and then kneading the mixture. As the hardening speed regulating agent, polyhydric alcohol such as ethylene glycol, mannitol, sorbitol, glycerol, etc., and monohydric alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, etc., may be used.

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Saitama, Japan

Osamu Nishida