JPS61113755A - Manufacture of metallic material with thermal sprayed ceramic film having high corrosion and heat resistance - Google Patents

Abstract

PURPOSE:To obtain a metallic material with a film having improved corrosion resistance by irradiating laser beams on a thermal sprayed ceramic film formed on the surface of a metallic material to melt the ceramic film. CONSTITUTION:A film of ceramics such as metallic oxide, nitride or carbide is formed on the surface of a metallic material by a thermal spraying method. Laser beams are irradiated on the thermal sprayed film in an inert atmosphere to melt the film. By this treatment, a molten film causing no degeneration is formed, and many micropores in the film disappear. As the temp. of the film is increased, the structure is made dense, and a metallic material with a thermal sprayed film having improved corrosion resistance is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Fields of Application of 1゛ζ Industry] The present invention relates to a method for manufacturing a metal material having a ceramic sprayed rupture film formed thereon with excellent corrosion resistance.

[Prior art]

Corrosion resistant and chemical resistant (n
forming a metal, alloy or ceramic coating,
It is a common practice to protect the metal materials from corrosion or attack by straw products.

As a means of forming these corrosion-resistant or chemical-resistant coatings on metal materials, in addition to methods such as plating or adhesion, coating formation methods by thermal spraying have recently become popular.

However, the method of forming a film by thermal spraying is extremely convenient compared to other methods of forming a film, such as plating or vapor deposition, and it is also possible to select materials with extremely high melting points such as ceramics as the material for forming the film. Although there are advantages, there are many fine pores in the coating layer, which deteriorate the coating strength and cause deterioration in corrosion resistance and chemical resistance.

In order to protect metal materials having such thermal sprayed coatings from corrosion and chemical attack, pore sealing treatment is generally performed in which the pores are filled with a 1fFL agent such as plastic.

Further, JP-A-56-112458 discloses a heat treatment method using an electron beam or plasma arc to alloy the coating and the metal substrate at their interface and improve coating adhesion.

[Problem that the invention seeks to solve]

However, these known film processing methods require complicated equipment such as maintaining a high vacuum, and are not suitable for processing a large area of radiation surface.

The present invention has been made for the purpose of providing a method for treating a ceramic spray coating 11, which does not have the above-mentioned drawbacks and can process a large area of coating very easily and at low cost.

Means for Solving Problem C] Hereinafter, means for solving the above problem will be specifically explained.

The metal material to be applied in the present invention is not particularly limited, and metals such as steel, nickel, metal, titanium, zirconium, etc., or alloys thereof may be arbitrarily selected depending on the intended use. Although it is possible, Zn+Sn, etc., which have a low melting point, are easily melted, so it is not very suitable.

In the present invention, the coating material to be formed on the surface of the metal material by thermal spraying is A1203, 7i02.5iQ2.
.

Or one or two nitrides or carbides of various metals.
More than one species can be selected and used as needed.

Hereinafter, in the present invention, the above-mentioned coating materials will be collectively referred to simply as ceramic.

The above ceramics can be manufactured by plasma spraying, arc spraying,
Alternatively, it is coated by a gas flame spraying method or the like on the surface of a metal material that has been previously cleaned to a surface condition suitable for thermal spraying through a known pretreatment such as shot blasting.

The thickness of the ceramic sprayed coating thus formed is not particularly limited, and can be arbitrarily selected, such as 50 μm or 300 μm, depending on the intended use.

The ceramic spray-coated metal material obtained as described above is irradiated with a laser beam in an inert atmosphere to melt the coating layer.

The atmosphere for the laser beam irradiation treatment in the present invention needs to be an inert atmosphere such as Ar gas, and in an oxidizing atmosphere such as air, the heat generated by the laser beam irradiation is, for example, 1000 to 2000°C, or Since the temperature is higher than that, there is a danger that the coating material will burn out and disappear. In addition, in a reducing atmosphere such as CO gas or N2 gas, ceramic coatings, 1. [
The membrane material is reduced and altered.

Therefore, in the present invention, the atmosphere during the laser beam irradiation treatment is an inert gas atmosphere.

The gas in the above atmosphere in the present invention is most preferably Ar gas, CO2 gas, or a mixture thereof, but N
When two gases are used as the atmospheric gas, nitrides are generated, and if the formation of nitrides is undesirable, care must be taken to avoid the presence of N2 in the atmospheric gas.

Further, when performing the laser beam treatment in the above-mentioned inert gas atmosphere, better quality treatment results can be obtained by preheating the metal material to 350° C. and maintaining it at this temperature.

The type of laser used to irradiate the thermally sprayed coating in the present invention is not particularly limited, but can be arbitrarily selected, such as a CO2 laser.

Furthermore, the heating temperature by irradiation with a laser or the like is most preferably approximately just above the melting point of the coating material, so that the ceramic sprayed coating is melted and fused.

〔Effect of the invention〕

Since the ceramic thermal spraying treatment method of the present invention is as described above, a molten film is formed without film deterioration even though the heat generated by laser beam irradiation is extremely high. The many fine pores that had been present in the coating disappeared, and as the coating temperature increased, the coating became denser and corrosion resistance was significantly improved.

〔Example〕

The method for laser beam thermal spraying of a ceramic thermal spray coating according to the present invention is as described above, and further examples thereof will be described below.

After the surface of the steel plate was cleaned by Noyonoto blasting to a surface quality suitable for forming a sprayed coating, a ceramic spraying material having the composition shown in Table 1 was applied to it by plasma arc spraying.
A sprayed coating was formed to a thickness of 0.00 μm.

Table 1 A CO2 laser with an output of about 50% was applied to the sprayed coating layer of the above ceramic sprayed steel sheet in a container filled with Ar gas.
The beam was irradiated at a speed of 0.07 m /+min to heat and melt.

In the treated coating obtained in this way, the thermal spray particles forming the coating were melted and fused, and the fine pores that had been enclosed within the coating layer were almost completely eliminated.
JIS Z2371) was conducted, and the corrosion resistance was significantly improved compared to untreated thermal sprayed steel sheets.

Claims (1)

[Claims] 1. After forming a ceramic spray coating on the surface of a metal material, irradiating the spray coating with a laser beam in an inert atmosphere,
A method for producing a highly corrosion-resistant and heat-resistant ceramic thermal spray coating-forming metal material, the method comprising melting the coating.