Method for forming thermal spray coating film of intermetallic compound, thermal spray coating film, method for producing metal product having spray coating film and glass-conveying roll

Abstract

To provide a method for forming a thermal spray coating film, by forming a thermal spray coating film of an Al—Fe based intermetallic compound having a high hardness, on a metal substrate.A method for forming a thermal spray coating film, by forming a thermal spray coating film of an Al—Fe based intermetallic compound, from a mixture of an Al—Fe based intermetallic compound powder composed mainly of FeAl2 and a metal powder composed mainly of Fe, as feedstock, on the surface of a metal substrate.

Description

TECHNICAL FIELD[0001]The present invention relates to a method for forming a thermal spray coating film of an intermetallic compound on the surface of a metal substrate, and a thermal spray coating film of an intermetallic compound. In particular, the present invention relates to a method for forming a thermal spray coating film of an Al—Fe based intermetallic compound, on the surface of a metal substrate made of iron or an iron-based alloy, and a thermal spray coating film of an intermetallic compound formed. Further, the present invention relates to a method for producing a metal product comprising a metal substrate having the thermal spray coating film, by the method of forming the thermal spray coating film, and a glass-conveying roll comprising a metal product having the thermal spray coating film.BACKGROUND ART[0002]Heretofore, in a step for producing a glass plate by float process, a variety of glass-conveying rolls such as a lift-out roll for pulling up a continuous layer of...

AI Technical Summary

Benefits of technology

The present invention provides a method for forming a high-quality thermal spray coating film made of an Al—Fe based intermetallic compound that has high hardness and is not prone to hydrogen embrittlement by quenching. The coating film has high toughness and can be applied to a wide range of substrate sizes and shapes. Additionally, the method results in a coating film with a small difference in linear thermal expansion coefficient with the metal substrate, which helps to prevent peeling of the coating film.

Problems solved by technology

For example, a glass ribbon immediately after being taken out from a tin bath has a sufficiently high temperature, and if the surface of a roll is made of a metal composed mainly of iron, microscopic adhesion easily occurs between the roll and the glass ribbon.

Since a metal roll is excellent in heat conduction, a minute glass residue adhering to the surface of the metal roll is easily deprived of heat and solidified, and thereby scratches the surface of a glass ribbon subsequently conveyed.

In such a case, the surface of the metal roll tends to corrode, and, as a result, contaminate the glass, but no corrosion occurs in the case of a ceramic coating.

(1) Size of a treatment furnace is restricted since the treatment is batch treatment.

(2) A metal substrate may deteriorate due to high-temperature treatment in the vicinity of 1,000° C.

(3) As shown in the after-mentioned Examples, a coating film formed by calorizing treatment is brittle, and therefore the coating film may be peeled from the metal substrate when used for a glass-conveying roll.

However, a conventional Al—Fe based thermal spray coating film has the following problems.

In an application where ductility is required for the thermal spray coating film, the ductility is preferred film properties, but in a case where such a film is applied to a glass-conveying roll, there are problems from the viewpoint of low hardness, and a possibility of hydrogen brittleness due to formation of excess pores by quenching.

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