US 5,958,152 A · Chromized heat-resistant alloy members and a process for the production thereof

Abstract

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.

Claims21

Dependent claims

A process for producing a chromized heat-resistant alloy member comprising the steps of:

packing a Ni- or Co-based heat resistant alloy member in a powder consisting essentially of chromium, aluminum oxide, and not more than one percent by weight, based on the powder of ammonium halide;
and
introducing hydrogen gas to the powder pack at a temperature ranging from 600-1100.degree. C. for a time sufficient to form a chromized layer on the Ni- or Co-based heat resistant alloy, the chromized layer having a chromium concentration of 25-80% and a thickness of 10-100 .mu.m.

Dependencies are inferred from the claim text.

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

Life of this patent

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

Life of this patent

Abstract

Claims21