Ebara Corporation

Tocalo Co., Ltd.

Masamichi Kawasaki

Yoshio Harada

Hisamichi Nagahara

Shuhei Nakahama

Syuhei Nakahama

Hiroshi Yakuwa

Toshio Narita

Matsuho Miyasaka

Junichi Takeuchi

To provide heat-resistant alloy members that maintain the resistance to corrosion at high temperature of the chromized layer formed on Ni- or Co-base heat-resistant alloys and which yet are improved in various mechanical properties. The improved Ni- or Co-base heat-resistant alloy member having a chromized layer that is characterized by having a chromium concentration of 25-80% and a thickness of 10-100 .mu.m. This member is produced by controlling both the vapor pressure of a chromium halide being used in chromization and the temperature therefor in such a way that the chromized layer being formed is adjusted to have a chromium concentration and a thickness within the ranges specified above.

Chromized heat-resistant alloy members and a process for the production

A high-temperature sulfidation-corrosion resistant nickel-base alloy includes 12.about.15 weight % of cobalt, 18.about.21 weight % of chromium, 3.5.about.5 weight % of molybdenum, 0.02.about.0.1 weight % of carbon, at most 2.75 weight % of titanium, and at least 1.6 weight % of aluminum. The remainder is essentially of nickel except for impurities. The high-temperature sulfidation-corrosion resistant nickel-base alloy has sufficient high-temperature strength and is highly resistant to a high-temperature sulfidation corrosion.

High-temperature sulfidation-corrosion resistant nickel-base alloy

Thermally sprayed coatings made from carbides of metals having greater carbon affinity than Cr in the presence of free carbon, or thermally sprayed coatings made from carbides of metals having smaller carbon affinity than Cr are heat treated in a chromium halide containing atmosphere which also contains hydrogen gas, whereby activated metallic Cr is precipitated in a fine particulate form, which is allowed to act on the thermally sprayed coatings, whereupon a Cr.sub.23 C.sub.6 -form carbide is created not only on the coating surface but also in its interior, particularly within pores, to form a modified layer, thereby compositing the thermally sprayed coatings.

Method of forming carbide-base composite coatings, the composite

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Tokyo, Japan

Masamichi Kawasaki