JPH11350105A - Structural member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structural member having excellent heat resistance or corrosion resistance or both of them, which has a ceramic layer having high ductility, denseness and adhesion of a coating film and low porosity. SOLUTION: In a structural member used in environment contg. the atmosphere or a gas at a high temp. over 250 deg.C or in an aq. solution environment at a high temp. over 100 deg.C, the structural member comprises either of ceramic, metal, an alloy or an intermetallic compd. and has a ceramic layer solidified through being half-melted or melted on the surface of the structural member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a member manufactured by surface modification by a novel method, and to an atmosphere containing air or gas at a high temperature exceeding 250.degree.
The present invention relates to a structural member suitable for use in an aqueous solution environment at a high temperature exceeding the above.

[0002]

2. Description of the Related Art In an environment containing air or gas at a high temperature exceeding 250 ° C., or in an aqueous solution environment at a high temperature exceeding 100 ° C., unlike the case where it is used at room temperature, the deterioration of the material at a high temperature is taken into consideration. Materials with high strength at high temperatures and materials with excellent corrosion resistance at high temperatures are used. When used in an atmosphere containing gas or air at a temperature higher than 250 ° C, creep strength at high temperature, oxidation at high temperature, and corrosion damage by corrosive gas are important. Have been used. At relatively high temperatures, metal alloys have been used at relatively low temperatures, and at higher temperatures, ceramics and composite materials have been used. Further, when used in an aqueous solution environment at a high temperature exceeding 100 ° C., corrosion due to an electrochemical reaction in the aqueous solution is a problem. Depending on the impurities dissolved in the aqueous solution, significant corrosion damage is caused, leading to breakage.
In an aqueous solution environment at a high temperature exceeding 100 ° C., a high-temperature and high-pressure environment is established, so that the higher the temperature, the greater the damage. Generally, a material having high corrosion resistance has been selected and used so as not to cause such damage.

In addition to such heat-resistant or corrosion-resistant materials, techniques for coating the surface of a structural member with such heat-resistant or corrosion-resistant ceramics have also been widely applied. As the surface coating technique, various plasma spraying techniques and the like are widely applied. In addition, the plasma-sprayed surface is modified with a laser to remove the non-uniformity of the coating and improve the strength.

[0004]

Various thermal spraying methods include flame spraying, arc spraying, plasma spraying, and explosive spraying. For ceramics, low-pressure plasma spraying, which has a high plasma temperature, is used. . The reduced pressure plasma spraying method is characterized in that plasma spraying is performed in a reduced pressure chamber in which the atmosphere is controlled.Therefore, compared with spraying in the air, there is no reaction of spray particles with the air and the number of pores is reduced. But not enough, and the adhesion between the film and the base material is not sufficient. In addition, the ductility of the film is low and the denseness is not sufficient.

[0005] In order to make up for the drawbacks of coating by such thermal spraying, it has been practiced to re-melt the thermal sprayed surface with a laser. The effect and the adhesion between the film and the base material are not improved, which is problematic.

SUMMARY OF THE INVENTION An object of the present invention is to provide a structural member having a ceramic layer having high ductility, denseness and adhesion, and having few pores, having excellent heat resistance and / or corrosion resistance, or both.

[0007]

SUMMARY OF THE INVENTION The present invention is directed to an atmosphere containing air or gas at a high temperature exceeding 250.degree.
In a structural member used in an aqueous solution environment at a high temperature exceeding 100 ° C., the surface containing the ceramics existing on the surface of the structural member made of any of ceramics, metal, alloy, and intermetallic compound is irradiated by a laser, 10
A structural member having excellent heat resistance and / or corrosion resistance, or both, by partially semi-melting or melting and solidifying a depth of 0 μm or more and less than 10% of the thickness of the member.

The present invention relates to a structural member used in an environment containing air or gas at a high temperature exceeding 250 ° C. or an aqueous solution environment at a high temperature exceeding 100 ° C. The surface after spraying the powder containing ceramics on the surface of the compound structural member by the high-speed powder flame spraying (HVOF) method is irradiated with a laser, and the surface depth is at least 100 μm or more and less than 10% of the member thickness. It is characterized by having excellent heat resistance and / or corrosion resistance by partially semi-melting or melting and solidifying.

The present invention is particularly directed to structural ceramic surfaces,
Alternatively, the surface of the metal, alloy, or intermetallic compound structural member after thermal spraying a coating powder containing ceramic particles having a particle temperature of 2,000 ° C. or more and a particle velocity of 600 m / sec or more is irradiated with a laser, and A structure characterized by having excellent heat resistance and / or corrosion resistance, or both, which is manufactured by partially semi-melting or melting and solidifying a depth of 100 μm or more and less than 10% of the thickness of the member. In the member.

The present invention also includes a structural member characterized in that the ceramic present on the surface of the structural member is an oxide or a ceramic containing an oxide film. 50% or more of ceramics or ceramics present on the surface of a metal, alloy, or intermetallic compound structural member.
A surface containing at least one of an alloy and an intermetallic compound is irradiated with a laser to partially or partially melt or melt or solidify a depth of less than 10% of the thickness of the member, thereby providing excellent heat resistance or corrosion resistance, or It is characterized by having both of them.

[0011] The surface of the structural member composed of one or two or more of oxides, carbides, nitrides, and borides of ceramics is irradiated with a laser, and the thickness of the member is 10% of the thickness of the member. A structural member having excellent heat resistance or corrosion resistance, or both, by partially semi-melting, melting, or solidifying a depth of less than one.

As a structural member, a tubular structural member made of ceramics or any one of a metal, an alloy, and an intermetallic compound, and one or both surfaces of ceramics present on an inner surface and an outer surface thereof are irradiated with a laser. A structural member having excellent heat resistance or corrosion resistance, or both, by irradiating and partially semi-melting, melting or solidifying a depth of less than 10% of the thickness of the member.

The present invention relates to a structural member used in an environment containing air or gas at a high temperature exceeding 250 ° C. or an aqueous solution environment at a high temperature exceeding 100 ° C., and particularly excellent heat resistance and / or corrosion resistance. Gas turbines, jet engines, refuse incinerators,
Waste power generation, coal gasification, nuclear fission reactor, fusion reactor, reprocessing,
Structural components of waste treatment and chemical plants.

[0014] Atmosphere or gas containing environment at a high temperature exceeding 250 ° C, or 100 ° C to be solved by the present invention.
In order to provide a surface coating structural member that has excellent heat resistance and / or corrosion resistance in an aqueous environment at a high temperature that exceeds the above, it is achieved by a new technology that overcomes the disadvantages of the plasma spraying conventionally used it can.
As a result of studying various surface coating technologies, conventional vacuum plasma spraying and high-speed powder flame spraying (HVOF)
We have found a technology that enables coatings that have high ductility, denseness, and adhesiveness, have few pores, and have excellent heat resistance or corrosion resistance, or both. Basically, a surface containing ceramics or ceramics existing on the surface of a metal, alloy, or intermetallic compound structural member is irradiated with a laser and has a depth of at least 100 μm or more and less than 10% of the member thickness. That is, partial melting or melting and solidification, and it has been found that the object can be achieved by appropriately combining an appropriate thermal spraying method and this laser irradiation.

The surface of the structural ceramic or the surface of the metal, alloy, or intermetallic compound structural member after the ceramic-containing powder is sprayed by the high-speed powder flame spraying (HVOF) method is irradiated with a laser, and at least the surface depth is increased. Sa1
This is achieved by partially semi-melting or melting and solidifying a depth of at least 00 μm and less than 10% of the thickness of the member.
Particle temperature 2000 ° C or higher, particle velocity 6 on the surface of structural ceramics or metal, alloy, or intermetallic compound structural member
The surface after spraying the coating powder containing the ceramic particles having a speed of not less than 00 m / sec is irradiated with a laser, and a depth of at least 100 μm or more and less than 10% of the thickness of the member is partially reduced. A structural member characterized by having more excellent heat resistance and / or corrosion resistance by semi-melting or melting and solidifying is obtained. Ceramics are effective with ceramics containing an oxide or oxide film.

In addition, 50% of ceramics or ceramics existing on the surface of the metal, alloy, or intermetallic compound structural member are present.
% Or more, and irradiates a laser to the surface containing at least one of metals, alloys, and intermetallic compounds in addition to ceramics.
It is also effective when a part of the member having a depth of less than 10% is partially melted or melted and solidified. In the case of containing particles in such a composite state, by selecting appropriate conditions, the film has higher ductility, denseness, and adhesion, has fewer pores, and has excellent heat resistance or corrosion resistance, or both. A combined coating film is obtained. Depending on the purpose, the ceramic particles for coating may be used alone or in combination of two or more of oxides, carbides, nitrides and borides.

[0017] A film obtained by irradiating a plasma-sprayed coating with a laser originally has many pores and poor adhesion to the plasma-sprayed coating, so that a large improvement cannot be expected even by laser irradiation. In the case of the high-speed powder flame spraying (HVOF) method, a good film cannot be obtained because the flame temperature is low and the spraying alone does not melt sufficiently and collides with the substrate, but the film is improved by remelting with a laser. You. However, a surface coating sprayed with a coating powder containing ceramic particles having a particle temperature of 2000 ° C. or more and a particle velocity of 600 m / sec or more has higher ductility, denseness, and adhesion, and has less pores. By irradiating with a laser and partially semi-melting, melting or solidifying a depth of at least 100 μm or more and less than 10% of the thickness of the member, it has more excellent heat resistance or corrosion resistance, or both. A structural member characterized by the above is obtained.

In laser irradiation, at least a surface depth of 10
A part having a depth of 0 μm or more and less than 10% of the thickness of the member is partially melted or melted and solidified.
If the thickness is less than μm, the surface thickness is too small and the heat and corrosion resistance functions are not sufficient, and if the thickness is 10% or more of the wall thickness, cracks occur due to thermal stress and the like, and a sound film cannot be formed.

The present invention is effective in an environment containing air or gas at a high temperature exceeding 250 ° C. or an aqueous environment at a high temperature exceeding 100 ° C. In an atmosphere containing gas or air at a high temperature of less than 250 ° C., the temperature is low, and heat resistance and corrosion resistance mainly due to oxidation are not large. 1
Corrosion in an aqueous solution environment at a high temperature of less than 00 ° C. is not large, and the effect of the present invention is small.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Example 1) A main component of a thermal spray material was alumina powder having a particle size of 12 μm, and a powder containing a slight amount of titanium oxide was used at an alumina particle temperature of 2,000.
After spraying onto the surface of the sintered alumina base material at a temperature of 800 ° C. and an average alumina particle speed of 800 m / sec, the surface was re-melted with a carbon dioxide gas laser. As a result of a bending test of this specimen at 1800 ° C., no peeling was observed at the boundary between the base material and the coating, and the specimen exhibited the same strength and ductility as the alumina single crystal. On the other hand, after coating the same powder by reduced pressure plasma spraying, the surface was remelted with a carbon dioxide gas laser, and a test specimen was bent at 1800 ° C. As a result, peeling was observed at the boundary between the base material and the coating,
In addition, the coating had many pores, and the coating was cracked at a low load.

(Example 2) The coating layer of the present invention prepared in Example 1, and the conventional coating layer prepared for comparison, at 1600 ° C, basicity CaO / SiO ₂ : 1.
Corrosion resistance test in 24 hours in 25 molten ash and 1600 ° C.
A water-cooled repeated thermal shock test was performed. As a result, the test piece of the present invention had an erosion amount of 0.5 mm, and the number of repetitions of the thermal shock test until crack initiation reached 50 times. On the other hand, in the conventional coating layer, the amount of erosion was 3.0 mm, and the number of repetitions until crack initiation was 5 times.

Example 3 A sprayed material has a particle size of 12 μm.
m of zirconia powder as a main component, a special gun obtained by adding an appropriate amount of hydrogen to a fuel gas at a zirconia particle temperature of 2850 ° C. and a zirconia average particle velocity of 900 m / sec. After spraying on the surface of the wing surface, the leading edge of the wing is irradiated with a carbon dioxide laser,
The surface portion of the sprayed layer was re-melted. The zirconia coating layer and the wing material are provided with CoN having excellent high-temperature corrosion resistance.
The iCrAlY alloy layer was previously coated. By such a method, the surface of the CoNiCrAlY alloy layer is 0.4 m thick.
A zirconia-based coating layer was prepared in which 0.15 mm of the surface portion was remelted at m. For comparison, a sturbine blade was formed by forming a coating layer by plasma spraying in a reduced-pressure atmosphere using the same zirconia-based powder and re-melting the leading edge. These gas turbine blades are operated at a gas temperature of 16
A heat cycle test was repeated in which heating was performed while cooling the inside of the blade and cooling outside the combustion cylinder by exposing to a combustion flame at 50 ° C. The heat flow rate in the heating state is 5.5 MW / m ² and the heating time is 10 minutes. As a result of the test, in the gas turbine blade provided with the coating layer of the present invention, peeling damage of the coating layer was not recognized even after 500 repetitions, but in the comparative example, peeling of the zirconia-based coating layer at the blade leading edge was performed in 20 times. occured. Therefore, it has been clarified that the zirconia-based coating layer of the present invention has sufficient heat resistance even under a high heat load environment.

[0023]

The present invention requires an environment containing air or gas at a high temperature exceeding 250 ° C., or an aqueous solution environment at a high temperature exceeding 100 ° C., particularly, having excellent heat resistance or corrosion resistance, or both. Gas turbine
Significant effects can be obtained in jet engine, refuse incinerator, refuse power generation, coal gasification, nuclear fission reactor, fusion reactor, reprocessing, waste treatment, and structural components of chemical plant.

Claims (8)

[Claims] 1. A structural member used in an environment containing air or gas at a high temperature exceeding 250 ° C. or an aqueous solution environment at a high temperature exceeding 100 ° C., wherein the structural member is made of ceramics, metals, alloys and intermetallic compounds. And a semi-melted or molten ceramic layer solidified on the surface of the structural member. 2. A structural member used in an environment containing air or gas at a high temperature exceeding 250 ° C. or an aqueous solution environment at a high temperature exceeding 100 ° C., from any of ceramics, metals, alloys, and intermetallic compounds. The surface after spraying a powder containing ceramics on the surface of the structural member by high-speed powder flame spraying (HVOF) method is irradiated with a laser, and has a depth of at least 100 μm or more and less than 10% of the thickness of the member. A structural member characterized by having a ceramic layer solidified by semi-melting or melting. 3. A structural member used in an environment containing air or gas at a high temperature exceeding 250 ° C., or an aqueous solution environment at a high temperature exceeding 100 ° C., from any of ceramics, metals, alloys, and intermetallic compounds. Particle temperature 2000 ° C or higher, particle velocity 600m / sec
The surface after spraying the coating powder containing the ceramic particles having the above speed is irradiated with a laser to semi-melt or melt at least a surface depth of 100 μm or more and less than 10% of the thickness of the member. A structural member having a ceramic layer solidified by solidification. 4. A structural member according to claim 1, wherein said ceramic layer is a ceramic containing an oxide or an oxide film. 5. The structural member according to claim 1, wherein 50% or more of ceramics, ceramics present on the surface of the metal, alloy, or intermetallic compound structural member are present, and metals, alloys, etc. other than ceramics are present. A structural member characterized in that a surface containing at least one of the intermetallic compounds is irradiated with a laser to solidify a part of the member having a depth of less than 10% of its thickness by semi-melting or melting. 6. A surface formed by combining one or more of oxides, carbides, nitrides, and borides of ceramics present on the surface, and irradiating the surface with a laser to reduce the thickness of the member to 10%. The structural member according to any one of claims 1 to 6, wherein the structural member is semi-molten or melted and solidified to a depth of less than 10%. 7. The structural member according to claim 1, wherein the structural member is a ceramic or a tubular structural member of a metal, an alloy, or an intermetallic compound, and the ceramic member present on an inner surface and an outer surface thereof. A structural member characterized by irradiating one or both surfaces with a laser and semi-melting or melting and solidifying a depth of less than 10% of the thickness of the member. 8. The structure according to claim 1, wherein the structural member is a gas turbine, a jet engine, a refuse incinerator, a refuse power generation, a coal gasification, a nuclear fission reactor, a nuclear fusion reactor, a reprocessing, a waste treatment. , A structural member of a chemical plant.