Wear Resistant Alloy Powders and Coatings

Abstract

This invention relates to alloys and wear resistant alloy powders useful for deposition through thermal spray devices. The alloys comprise from about 20 to 65 weight percent chromium, about 20 to 65 weight percent molybdenum, about 0.5 to 3 weight percent carbon, and about 10 to 45 weight percent nickel. The wear resistant alloy powders are useful for forming coatings having the same composition.

Description

FIELD OF THE INVENTION[0001]This invention relates to chromium-molybdenum alloys and wear resistant alloy powders useful for deposition through thermal spray devices. The wear resistant alloy powders are useful for forming coatings having the same composition.BACKGROUND OF THE INVENTION[0002]Hard surface coating metals and alloys are known in the art. For example, chromium metal has been used as an electroplated coating for many years to restore worn or damaged parts to their original dimensions, to increase wear and corrosion resistance, and to reduce friction. Hard chromium electroplate, however, has a number of limitations. When the configuration of the part becomes complex, obtaining a uniform coating thickness by electro-deposition is difficult. A non-uniform coating thickness necessitates grinding to a finished surface configuration, which is both difficult and expensive with electroplated chromium because of its inherent brittleness and hardness. The rate of deposition by ele...

AI Technical Summary

Benefits of technology

This patent is about a new type of alloy that contains a lot of chromium, molybdenum, carbon, and nickel. The alloys also have small amounts of carbides and nitrides mixed in. This patent also describes a new type of powder that can be used to make coatings with the same composition. The technical effect of this invention is that it provides a way to make alloys and powders that have excellent resistance to wear and corrosion.

Problems solved by technology

Hard chromium electroplate, however, has a number of limitations.

When the configuration of the part becomes complex, obtaining a uniform coating thickness by electro-deposition is difficult.

A non-uniform coating thickness necessitates grinding to a finished surface configuration, which is both difficult and expensive with electroplated chromium because of its inherent brittleness and hardness.

It is often necessary to apply one or more undercoats, or to use expensive surface cleaning and etching procedures to prepare substrates.

Disposal of spent plating baths also adds significantly to the cost of the process.

However, considerable finishing may be required for certain coatings with wear resistance tailored for specific applications.

However, there are certain limitations to the quality of coatings made from them.