JP2747088B2 - Thermal spray coating material and thermal spray coating heat resistant member - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a thermal spray coating material having excellent heat insulation provided with heat resistance, which is used for thermal spray coating for improving the surface of ceramics and metals, and the like. Among the techniques for improving the high-temperature durability of heat-resistant components, the present invention relates to a heat-resistant member coated with these thermal spray coating materials by an optimal plasma spraying method, particularly as a component for a gas turbine or the like.

[Prior Art] The high-temperature characteristics required for heat-resistant and heat-shock resistant members are increasing in severity year by year. Above all, gas turbines exhibit higher efficiency as they are operated at higher temperatures, so that their operating temperatures are constantly required to increase. Therefore, materials that have both heat resistance and thermal shock resistance that can respond to it
Fine ceramics such as i ₃ N ₄ are being studied, but at present, gas turbine components are manufactured based on metal materials because of problems in impact strength.

However, the use of heat-resistant metal materials such as Ni-based and Co-based materials is limited to 1000 ° C. or lower. Therefore, when they are applied to gas turbine components, various methods for cooling or heat shielding have been studied. Heat shielding is to form a ceramic layer on the surface of a metal (hereinafter, referred to as a base material) of a high-temperature heat-resistant component such as a gas turbine, thereby lowering the base material temperature.
Conventionally, ceramic powder having low thermal conductivity, high thermal shock resistance and high emissivity has been used as a material for thermal spray coating.

Zr to which rare earth oxides such as Y ₂ O ₃ are added as a stabilizer as a material that has been used in such applications so far.
O _{2 and the} like. However, even with thermal spray coatings obtained using this currently best thermal spray material, quenching,
In a gas turbine to which a rapid thermal cycle can be applied, the coating layer tends to peel off from the base material and lose its function. In addition, since these materials use rare earth oxides, if they are used alone, the price is high, and the sprayed materials produced are also very expensive, so they must be used in large quantities for structural materials for industrial use. Is quite costly.

In general, when a thermal spray coating is used under intense heat cycles of rapid heating and quenching, thermal distortion occurs between the base material and the coating, and it cannot follow the rapid thermal expansion of the base material, causing cracking and peeling of the coating layer. Does not show excellent durability. For this reason, various developments have been made on thermal spraying materials having not only low thermal conductivity but also a coefficient of expansion close to that of the base material. Further, a layer composed of a mixture or a composite of both is provided between the metal and the ceramic layer, which are the main causes of peeling (see, for example, JP-A-55-113880).
Etc.), or by forming fine cracks in the ceramic layer by heat treatment at a high temperature for a long time (see, for example, JP-A-56-54905).
Various proposals have been made, such as a component having a ceramic layer, and a component in which fine cracks are formed in the layer by quenching after forming the ceramic layer (for example, JP-A-58-87273).

[Problems to be Solved by the Invention] However, although improvements have been made by the above-described conventional means, the effects thereof have been limited by the results of heat cycle tests and the like. The present invention takes this situation into account,
Thermal spray coating material having heat resistance and thermal shock with very low cost, high product yield, economical and extended life as compared with Y ₂ O ₃ -ZrO ₂ etc., and gas turbine parts provided with this It is an object of the present invention to provide such a thermal sprayed coated heat-resistant member.

[Means for Solving the Problems] The present inventors have intensively studied to find a material having heat resistance and thermal shock resistance. As a result, magnesium silicate and MgO, which also exist as natural resources,
・ We found that a combination of 4ZrO ₂ can provide a completely new and cheap thermal spraying material that does not use rare earth and has excellent heat resistance and thermal shock resistance.

That is, the present invention relates to a 1.2MgO · SiO ₂ -MgO · 4ZrO ₂ based oxide having a composition of
A thermal spray coating material characterized by the following expression: 20 ≦ 2MgO · SiO ₂ ≦ 50, 50 ≦ MgO · 4ZrO ₂ ≦ 80, and 2MgO · SiO ₂ + MgO · 4ZrO ₂ = 100.

2. In a component made of a heat-resistant metal material, the component has a metal coating layer provided on the surface of the metal coating layer which is equivalent to or more resistant to high-temperature corrosion than the heat-resistant metal material, and further has the first coating on the metal coating layer. A spray-coated heat-resistant member obtained by spraying the spray-coated material according to any one of the preceding claims.

3. Each of the oxide materials according to item 1 is a compound, a composite,
Or a material for thermal spray coating characterized by being particles of a mixture.

4. A material for thermal spray coating, wherein the particle size of the oxide material according to the above item 1 is adjusted to 5 to 500 μm, and particularly the average particle size is 10 to 100 μm.

5. A thermal spray-coated heat-resistant member, wherein the material for thermal spray coating according to item 2 is the material for thermal spray coating according to item 3.

It is.

 Hereinafter, the present invention will be described specifically.

The development of a thermal spray coating material using magnesium silicate as a starting material was attempted for a ceramic material that is stable at high temperatures, has a high heat resistance effect, has a relatively large coefficient of thermal expansion, and can be manufactured at low cost. Magnesium silicate compounds include “MgO.SiO ₂ ” and “2
MgO · SiO ₂ ”and the like are known. However, MgO ・ SiO ₂ is contained
Since the amount of SiO ₂ is relatively high, the adhesion to the base material is deteriorated due to the poor leakage at the time of thermal spraying, and cracks are generated by applying a heat cycle. From these results, 2MgO · SiO ₂ was selected as the magnesium silicate spray material. In order to further enhance the heat insulation and heat resistance effects, various studies have
ZrO ₂ was selected, and a plurality of these were used in the thermal spray coating material of the present invention. The use of a plurality of materials having such heat resistance and heat insulation effects is because heat resistance and heat insulation superior to conventional heat insulation materials are exhibited, and a highly reliable coating layer can be formed.

Mixtures and composites can be used for 2MgO · SiO ₂ , but it is effective to use pure mineral (forsterite). MgO · 4ZrO ₂ also compounds, can be used composites and mixtures, compounds or composites spray granulated in a spray dryer or the like are preferable. The material of the present invention is adjusted to a particle size of 5 to 500 μm, particularly an average particle size of 10 to 100 μm.
It is preferable to adjust the temperature.

The reason why the composition range of the present invention is limited as described above is as follows. When the content of 2MgO · SiO ₂ is more than 50% by weight, not only the coefficient of thermal expansion is too small to keep up with the coefficient of thermal expansion of the base material, but also as the content of SiO ₂ increases, the leak property becomes poor and peeling occurs. If the content of MgO.4ZrO ₂ is more than 80% by weight, the high-temperature stabilizing action is undesirably reduced. When the particle size of the thermal spray material of the present invention is 5 μm or less, the flow of the powder supplied to the thermal spray gun is poor, so that a good coating cannot be obtained, and the yield during thermal spraying also decreases. On the other hand, when the thickness is 500 μm or more, unmelted particles are formed in the thermal sprayed coating, and the adhesion of the coating is reduced.

The thermal spray material of the present invention is characterized in that two kinds of materials are combined, combined or mixed in various ratios. Thereby, the durability can be improved. Further, a coating obtained by spraying this material not only has excellent heat resistance and heat insulating properties, but also exhibits a hot expansion behavior similar to that of the base material. As a result, the present sprayed material which can suppress the peeling damage of the coating film has great industrial significance.

 Hereinafter, various embodiments of the present invention will be described.

The separation of the ceramic layer, which is the main cause of the shortening of the service life, is caused by thermal stress based on the difference in expansion coefficient between metal and ceramic.To alleviate this, various ceramics with a relatively large thermal expansion coefficient are selected to reduce thermal shock. The test was performed. The base material is a Ni-based alloy (IN939: Ni-Co-Cr-W alloy) of 50x50x5mm. After blast treatment with alumina powder, first, NiCrAlY alloy is 100μm reduced pressure plasma sprayed as a metal with high temperature corrosion resistance. Further, a sprayed material in which each ceramic shown in Table 1 was adjusted to an average particle size of about 30 μm was further plasma sprayed thereon. The obtained test piece was heated at 1200 ° C for 15 minutes,
It was subjected to a thermal shock test of cooling for 16 minutes, and the number of thermal cycles until crack initiation was investigated. The results are shown in Table 1.

From this test result, No. 6 2MgO.SiO ₂ -50wt% MgO.4Zr
That _{2MgO · SiO 2 -80wt% MgO ·} 4ZrO 2 from O ₂ No.11 has good thermal shock resistance shows a more durability ten thermal shock was found.

As for the 2MgO · SiO ₂ -MgO · 4ZrO ₂ -based raw material, it was found in this test that the composite was the best, and then the compound and the mixture were superior in thermal shock resistance in this order. Fig. 1 shows the No. 10 2MgO · SiO ₂ -70wt% Mg which showed good thermal shock resistance.
The cross section of the film is shown using O.4ZrO ₂ as a representative example. Many fine vertical cracks are present in the coating, and it is presumed that the thermal cracks have been improved by the vertical cracks.

[Example] Example 1 NiCrAlY was sprayed under reduced pressure of 0.1 mm onto the first and second stationary blades of a gas turbine for power generation using kerosene, and further, the material for thermal spray coating of the present invention was adjusted to an average particle diameter of about 30 μm. , 2MgO ・
SiO ₂ -50wt% MgO ・ 4ZrO ₂ (composite material), 2MgO ・ SiO ₂ -7
0 wt% MgO.4ZrO ₂ (composite material) was sprayed 0.2 mm each and used at turbine inlet gas temperature of 1100 ° C. for about 1 year, but it has been in good condition without peeling off of the coating of the present invention.

Example 2 NiCrAlY was vacuum-sprayed on the inner surface of the combustor of the gas turbine for power generation of Example 1 as an underlayer at a pressure of 0.15 mm, and test pieces No. 3, No. 4, and No. 10 shown in Table 1 were formed thereon. The same material was plasma-sprayed in the atmosphere by 0.3 mm each in the combustor inner cylinder, and the combustion chamber temperature was changed to 115.
After being used for one year at 0 to 1300 ° C., all of the No. 10 coatings of the present invention are sound and well-moving. Incidentally, the coatings of No. 3 and No. 4 which were used as comparative materials in the present example each had a turtle-shaped crack or peeling within 3 to 6 months.

[Effects of the Invention] As is clear from the above results, the material for thermal spray coating of the present invention has extremely high heat resistance and resistance to adiabatic impact resistance and excellent mechanical strength. By using a coating layer obtained by spraying the material for thermal spray coating of the present invention, it is possible to obtain a highly efficient and highly efficient turbine blade having excellent heat shielding effect and heat resistance, and because no rare earth oxide is used. This has the effect of greatly contributing to cost reduction.

[Brief description of the drawings]

FIG. 1 is a cross-sectional photograph showing the crystal structure of a 2MgO.SiO ₂ -75 wt% MgO.4ZrO ₂ (composite material) sprayed coating.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi Imawaka 1 Fujimachi, Hirohata-ku, Himeji-shi, Hyogo Nippon Steel Corporation Hirohata Works (72) Inventor Yoshio Harada Fukae, Higashinada-ku, Kobe-shi, Hyogo Kitamachi 4-13-4 Tokaro Co., Ltd. (72) Inventor Noriyuki Mifune 4-13-4 Fukae Kitamachi, Higashinada-ku, Kobe City, Hyogo Prefecture Inside Tokaro Co., Ltd. (72) Inventor Hiroshi Hagiwara 1499, Muro, Urawa City, Saitama Prefecture (72) Inventor Takayuki Yodoro 3-36-15 Nakamura, Nerima-ku, Tokyo (56) References JP-A-2-170963 (JP, A) JP-A-57-174440 (JP, A) JP-A-57 −183372 (JP, A)

Claims (5)

(57) [Claims] 1. A 2MgO.SiO ₂ -MgO.4ZrO ₂ based oxide having a composition of 20 ≦ 2MgO.SiO ₂ ≦ 50 and 50 ≦ MgO.4ZrO in weight%.
_A material for thermal spray coating, wherein ₂ ≦ 80 and 2MgO · SiO ₂ + MgO · 4ZrO ₂ = 100. 2. A component made of a heat-resistant metal material,
The component has a metal coating layer provided on the surface thereof, which is equivalent to or more resistant to high-temperature corrosion than the heat-resistant metal material, and the material for thermal spray coating according to claim 1 is further sprayed on the metal coating layer. A thermally sprayed coated heat-resistant member characterized by the following: 3. A material for thermal spray coating, wherein each oxide material according to claim 1 is a particle of a compound, a composite or a mixture. 4. The oxide material according to claim 1 having a particle size of 5
A material for thermal spray coating, wherein the material is adjusted to 500 μm, and particularly has an average particle diameter of 10 to 100 μm. 5. A thermal-sprayed heat-resistant member, wherein the material for thermal spray coating according to claim 2 is the material for thermal spray coating according to claim 3.