JPH1081957A - Evaporation material - Google Patents

Abstract

(57) Abstract: An object of the present invention is to provide a novel vapor deposition material for coating capable of forming a heat resistant film excellent in heat resistance and impact resistance even by the EB-PVD method, and a vapor deposition material for the same. It is to provide a vapor deposition method to be used. A sintered body made of zirconia containing a stabilizer, having a monoclinic content of 25 to 70%, a tetragonal content of 3% or less, and a balance of cubic, Further, the bulk density is 3.0 to 5.0 g / cm ³ and the porosity is 15 to 5
0%, the mode diameter of the pores is 0.5 to 3 μm and
A vapor deposition material characterized in that a pore volume of 1 to 5 μm occupies 90% or more of the total pore volume, and vapor deposition characterized in that a maximum value is 0.85 μm or more in a half value range of a pore diameter distribution curve. Material and a vapor deposition method using the vapor deposition material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an evaporation material for coating capable of forming a stable molten pool and having excellent heat resistance and impact resistance and capable of performing evaporation.

[0002]

2. Description of the Related Art A conventional method of forming a heat-resistant film is generally a thermal spraying method.
A method for forming a heat-resistant film by a physical vapor deposition method (hereinafter abbreviated as PVD method) has been put to practical use. Among them, Electron-beam
Attention has been paid to the EB-PVD method using
NCED MATERIAL & PROCESS, Vo
l. 140, no. 6, No. 12, p. 18-22
(1991)), a number of methods for forming a heat-resistant film by the EB-PVD method have been developed.

The above-mentioned method of forming a heat-resistant film by the EB-PVD method is used for heat-resistant coating on parts such as aircraft engines. The vapor deposition material used as the coating material is required to have excellent heat resistance because it is coated on parts where the high-temperature combustion gas is directly applied, and therefore it is necessary to have a high melting point and high purity. is necessary. In addition, it does not peel off due to adhesion to metal parts, does not peel off due to thermal cycling, does not corrode due to components of combustion gas, and has low thermal conductivity to increase the durability of metal parts, which is the purpose of this coating. It is desirable that the decrease in surface temperature be as large as possible. To date, few materials satisfy these requirements, and a sintered body obtained by sintering a molded body obtained by molding a zirconia powder containing a stabilizer such as yttria is mainly used.

[0004] The vapor deposition material made of a zirconia sintered body containing this stabilizer has a high melting point, and it is necessary to form a vapor deposition film at a high speed, so that an electron beam capable of evaporating the vapor deposition material with high energy. E using beam
The film is formed using a B vapor deposition method.

In this EB vapor deposition method, a high energy electron beam is rapidly applied to the vapor deposition material set in a crucible, so that a normal sintered body is broken by thermal shock.
If the vapor deposition material is broken, the supply of the vapor deposition material is hindered, and the vapor deposition material damaged by the electron beam is not practically usable.

Therefore, as means for solving the destruction due to the impact of the electron beam, vapor deposition materials having various characteristics have been proposed. Among them, a porous material is made by a certain method to improve heat resistance and thermal shock resistance. It has been proposed to do so.

[0007] For example, in DE4302167C1, Y ₂
O ₃ was contained 0.5 to 25 wt%, density 3.0 to 4.5
It describes a zirconia sintered body having a g / cm ³ , a monoclinic ratio of 5 to 80%, and a balance of tetragonal or cubic. If zirconia is not stabilized, during the heat treatment for vapor deposition material production, it is tetragonal and stable at high temperatures, but undergoes a phase change from tetragonal to monoclinic when the temperature drops, resulting in microcracking. Occurs. Here, it is described that the crack resistance is improved by the presence of the microcracks accompanying the presence of the monoclinic crystal, and the crack resistance is also improved by increasing the particle size to some extent.

However, when this zirconia sintered body is used in the above-mentioned applications, the heat resistance and the thermal shock resistance are insufficiently improved.
Cracks occur and long-term regular work is difficult. This is due to the presence of monoclinic crystals and the suppression of crack growth due to microcracks, or even when the particle size is increased to some extent, depending on the mixing state and pore size with Y ₂ O ₃ acting as a sintering aid. It is considered that sintering rapidly progresses due to rapid heating during EB irradiation, and the sintering cannot withstand the stress accompanying shrinkage due to sintering, resulting in destruction.

As another zirconia sintered body, Japanese Patent Application Laid-Open No. 7-82019 discloses that the purity is 99.8% or more and the particle size is 0.1.
A mixture of zirconia particles having a particle size of 10 μm to 10 μm and yttria particles having a particle size of 1 μm or less makes 70% or more of the mixture 45 to 300%
A sintered body obtained by granulating to a particle diameter of μm, performing heat treatment, and sintering zirconia particles in which 50% or more of the entire spherical aggregated particles have a diameter of 45 to 300 μm. A vapor deposition material for a heat-resistant coating comprising a zirconia porous sintered body having a porosity of 25 to 50% and a pore diameter of 0.1 to 5.0 μm occupying 70% or more of all pores has been proposed.

In this method, E is higher than that of the conventional vapor deposition material.
Although the cracking resistance due to B irradiation is improved, as described above, since this vapor deposition material is composed of powder particles having greatly different particle diameters, the microstructure of the vapor deposition material becomes non-uniform, and vapor deposition is performed. When the vapor deposition material is melted by EB irradiation, it is difficult to form a stable molten pool, the operation for forming a film becomes difficult, and the durability of the heat-resistant film formed by vapor deposition is poor.

[0011]

SUMMARY OF THE INVENTION An object of the present invention is to improve the thermal shock resistance during EB irradiation, which is a problem of these conventional vapor deposition materials, to prevent bumping of a molten liquid melted by EB irradiation, and to stabilize it. An object of the present invention is to provide a novel coating vapor deposition material having improved stability of the formation of a molten pool and the evaporation rate, and a vapor deposition method using the vapor deposition material.

[0012]

Means for Solving the Problems The present inventors have made intensive studies to solve the above problems, and as a result, completed the present invention.

That is, the present invention relates to a sintered body made of zirconia containing a stabilizer, wherein the monoclinic content is 25%.
-70% and the tetragonal content is 3% or less, the balance is cubic, and the bulk density is 3.0-5.0 g / cm.
³ , the porosity is 15 to 50% and the pore mode diameter is 0.5
Novel vapor deposition material for coating and a vapor deposition material characterized in that cracking does not occur during EB irradiation when a vapor deposition material having a pore volume of 3 to 3 μm and a pore volume of 0.1 to 5 μm occupies 90% or more of the total pore volume is used. The present invention relates to a vapor deposition method using

Hereinafter, a method for producing a deposition material according to the present invention will be described.

After a predetermined amount of zirconia powder having an average particle size of 0.05 μm to 10 μm and a stabilizing agent are prepared, they are dispersed and mixed in a mixing device such as a ball mill using an organic solvent such as water or ethanol. Even when a raw material powder having a larger particle diameter is used, it can be used as long as the particle diameter of the deposition material finally falls within a predetermined range by pulverizing with a ball mill or the like. The mixed slurry can be used with a usual drying device such as a spray drier, vacuum drying, and filter press. Further, an organic binder in the slurry can be added to facilitate molding.

Examples of the stabilizer referred to in the present invention include yttria, magnesium oxide, calcium oxide, scandium oxide, Group 6A rare earth metal oxides of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, cadolinium, Terbium, dysprosium, holmium, erbium,
Thulium, ytterbium, lutetium)
These stabilizers may be used alone, or two or more stabilizers may be used. The stabilizer is added in an amount of 0.1 to 40% by weight depending on the use.

The stabilizer is partly or wholly dissolved in zirconia. However, if the stabilizer is completely and uniformly dissolved, the crystal particle diameter becomes too large upon heating, which impairs the thermal shock resistance. Absent. For example, in the case of a zirconia sintered body to which 7.1 wt% of Y ₂ O ₃ is added, spot analysis is performed at random on 20 points for one sample by EPMA, and the stabilizer composition at each point is charged in wt%. When the standard deviation of the deviation from the composition is taken, this value is preferably 0.45 or more, more preferably 0.55 or more. When this value is small, that is, when the solid solution of the stabilizer is uniform, the thermal shock resistance at the time of EB irradiation is low and cannot be put to practical use.

The zirconia powder and the powder containing the stabilizer prepared to obtain the molded article of the present invention are usually filled in a rubber mold or the like, and molded using a cold isostatic pressing (CIP) apparatus. You. The molding pressure is not particularly limited in the present invention.

The molded body thus formed is usually subjected to a heat treatment. The heat treatment temperature is not particularly limited as long as it is equal to or higher than the temperature at which the binder and the adsorbed material are removed,
Usually, it is preferable to bake at 1000 ° C. or more.
It is more preferable to fire at a temperature of 00 ° C. or higher. The compact before heat treatment of the present invention has a small shrinkage due to heating itself,
Even when fired at 1450 ° C., the shrinkage rate is about 10% at the maximum. Even if the shrinkage rate is small, if shrinkage occurs from a temperature range of about 1000 ° C., the area where sintering proceeds by heating during EB irradiation becomes larger, and the range of stress generation also increases with the shrinkage. Therefore, this firing is effective in reducing shrinkage due to the progress of sintering during heating by the electron beam and suppressing cracking.

The present invention will be described in more detail. The vapor deposition material of the present invention is mainly composed of a sintered body made of zirconia containing a stabilizer, and the crystal phase of the sintered body has a monoclinic content ratio of 2%.
5 to 70%, the content of tetragonal crystal is 3% or less, and the remainder is cubic. When the monoclinic ratio is less than 25%, the thermal expansion and the crystal particle diameter become too large, and the thermal shock resistance is impaired, which is not preferable. On the other hand, when the monoclinic crystal ratio exceeds 70%, cracks are often generated due to the phase transition, cracks are generated, and the strength is unpreferably reduced. The monoclinic ratio is preferably from 30% to 60% from the viewpoint of maintaining thermal shock resistance and suppressing cracks accompanying phase transition. That is, the monoclinic phase undergoes a phase transition to a tetragonal phase during sintering of the compact at a temperature of 1000 ° C. or more, and at this time, the volume is reduced by about 4%. And the presence of monoclinic crystals produces many microcracks in the sintered body, and these microcracks have an effect of suppressing crack growth. As described above, the presence of the monoclinic contributes to an improvement in thermal shock resistance.

The tetragonal content is less than 3%, preferably substantially 0%. The reason is that, when the number of tetragonal crystals increases, the solid solution of the stabilizer in zirconia advances, and the composition of the vapor deposition material is uniform. This is because the impact strength is undesirably reduced.

The bulk density is 3.0 to 5.0 g / cm ^3.
The reason is that the bulk density is 5.0 g / cm ³
If the bulk density is more than 3.0 g / cm ³ , it is not preferable because the local stress during EB irradiation causes breakage due to thermal stress. On the other hand, if the bulk density is less than 3.0 g / cm ³ , the mechanical strength decreases and handling becomes difficult. Because there is no.

The porosity is 15 to 50%, and the pore volume of 0.1 to 5 μm occupies 90% or more of the total pore volume, preferably 95% or more. The reason for limiting the porosity to 15% to 50% is that if the porosity is less than 15%, it is not preferable because breakage occurs due to thermal stress due to local thermal expansion during EB irradiation.
If the porosity exceeds 50%, the mechanical strength is reduced and handling becomes difficult, which is not preferable. Also,
When the pore volume of the pore diameter of 0.1 to 5 μm is less than 90%, the thermal shock resistance becomes insufficient, which is not preferable.

The pore distribution is such that the pore mode diameter is 0.5-3.
It must be in the range of μm. The reason for this is that if the pore mode diameter is smaller than 0.5 μm and the amount of small pores increases, the pores disappear due to the progress of sintering due to heating during EB irradiation, and the function of making porous is lost. Conversely, when the pore mode diameter exceeds 3 μm, the amount of large pores is large, so that the mechanical strength of the vapor deposition material is reduced and the stability of the molten pool of the vapor deposition material is impaired.

In the half-value range (CD) of the pore diameter distribution curve shown in FIG.
It is preferably at least 85 μm. The reason is that if the maximum value is less than 0.85 μm, the pore diameter is 0.1 to 5 μm.
Even if the pore volume of μm occupies 90% or more of the total pore volume, the amount of pores having a small diameter increases as a whole, and the pores are easily extinguished during heating during EB deposition, and the thermal shock resistance is insufficient. It becomes something.

The particle size is 10 μm or less,
Preferably, it does not contain aggregated particles of 20 μm or more. If the particle size exceeds 10 μm or contains aggregated particles of 20 μm or more, it becomes difficult to partially melt when forming a molten pool by EB irradiation and melting the deposition material,
It becomes difficult to form a uniform and stable molten pool, the operation for vapor deposition becomes difficult, and the quality of the heat-resistant coating formed by vapor deposition deteriorates, and the durability decreases.

In the case of sintering at 1400 ° C., for example, grain growth occurs and the particle diameter of the vapor deposition material becomes larger than the particle diameter of the raw material powder. In such a case, the particle diameter of the vapor deposition material is 10 μm or less. It is preferred that Further, it is preferable that the vapor deposition material does not contain aggregated particles having a size of 20 μm or more due to insufficient dispersion and mixing or aggregation of the raw material powder in the dispersion medium. The agglomerated particles in the deposition material referred to here are densely aggregated particles, and the presence or absence of the agglomerated particles can be clearly confirmed by a scanning electron microscope.

The present invention further provides a method of forming a zirconia thin film on a substrate of metal, ceramics or the like using an evaporation material of the present invention by an electron beam evaporation apparatus, and a method of forming a metal or the like obtained by this method. Provide parts.

As described above, the physical properties and mixing conditions of the raw material powder are selected so that the vapor-deposited material has the desired range of physical properties, and the obtained mixed powder is molded and fired to prevent cracking during EB irradiation. It is possible to produce a novel heat-resistant coating material capable of performing stable vapor deposition without generation.

Further, the present invention also includes a method of using the vapor deposition material for coating to vapor-deposit on a desired substrate by an energy beam irradiation type vapor deposition method such as an electron beam.

[0031]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Example 1 An organic binder was added to 83.6 g of zirconia powder having an average particle size of 0.5 μm and 6.4 g of yttria powder having an average particle size of 0.2 μm, and 5 wt% (10 g) of an organic binder was added thereto. , Balls: 2.5 kg) for 1 hour, and then dried. The powder obtained was packed in a rubber mold (diameter 35).
mm, thickness 100 mm), molded at a pressure of 1 ton / cm ² by a wet cold isostatic pressing device (manufactured by Kobe Steel, 4 KB × 150 D × 500 L), and sintered at 1420 ° C. to produce a vapor deposition material. did.

Example 2 An organic binder was added to 83.6 g of zirconia powder having an average particle diameter of 0.8 μm and 6.4 g of yttria powder having an average particle diameter of 0.2 μm, and 5 wt% (10 g) was added to a ball mill (volume: 1 liter). , Ball: 2.5 kg) for 1 hour, and then dried. The powder obtained was packed in a rubber mold (diameter 35).
mm, thickness 100 mm), molded at a pressure of 1 ton / cm ² by a wet cold isostatic pressing device (manufactured by Kobe Steel, 4 KB × 150 D × 500 L), and sintered at 1420 ° C. to produce a vapor deposition material. did.

Example 3 An organic binder was added to 83.6 g of zirconia powder having an average particle size of 1.5 μm and 6.4 g of yttria powder having an average particle size of 0.2 μm, and 5 wt% (10 g) was added to a ball mill (volume: 1 liter). , Ball: 2.5 kg) for 1 hour, and then dried. The powder obtained was packed in a rubber mold (diameter 35).
mm, thickness 100 mm), molded at a pressure of 1 ton / cm ² by a wet cold isostatic pressing device (manufactured by Kobe Steel, 4 KB × 150 D × 500 L), and sintered at 1630 ° C. to produce a vapor deposition material did.

Example 4 1393.6 g of zirconia powder having an average particle diameter of 5 μm and 106.4 g of yttria powder having an average particle diameter of 2 μm were added to a ball mill (volume: 2.5 liter, ball: 7.5 k).
g) for 1 hour, dried, and the powder obtained was packed in a rubber mold (diameter 35 mm, thickness 100 mm), and wet cold isostatic pressing device (Kobe Steel, 4 KB × 150 D × 50).
0L type) at a pressure of 1 ton / cm ² and 1490
Sintering was carried out at ℃ to produce a deposition material.

Comparative Example 1 An organic binder was added to 83.6 g of zirconia powder having an average particle diameter of 0.8 μm and 6.4 g of yttria powder having an average particle diameter of 0.2 μm, and 5 wt% (10 g) was added to a ball mill (volume: 1 liter). , Ball: 2.5 kg) for 16 hours, and then dried. The powder obtained was packed in a rubber mold (diameter 35).
mm, thickness 100 mm), molded at a pressure of 1 ton / cm ² with a wet cold isostatic pressing device (manufactured by Kobe Steel, 4 KB × 150 D × 500 L type), and sintered at 1350 ° C. to produce a deposition material did.

COMPARATIVE EXAMPLE 2 5 wt% (10 g) of an organic binder was added to 83.6 g of zirconia powder having an average particle size of 1.5 μm and 6.4 g of yttria powder having an average particle size of 0.2 μm. , Ball: 2.5 kg) for 1 hour, and then dried. The powder obtained was packed in a rubber mold (diameter 35).
mm, thickness 100 mm), molded at a pressure of 1 ton / cm ² with a wet cold isostatic pressing device (manufactured by Kobe Steel, 4 KB × 150 D × 500 L type), and sintered at 1350 ° C. to produce a deposition material did.

Comparative Example 3 A rubber mold was filled with 100 g of zirconia powder in which 4 mol% of yttria having an average particle size of 0.2 μm was dissolved in solid form (diameter 3).
5 mm, thickness 100 mm), molded at a pressure of 1 ton / cm ² with a wet cold isostatic press (Kobe Steel, 4 KB × 150 D × 500 L type), and sintered at 1350 ° C. to produce a deposition material did.

Comparative Example 4 Zirconia powder in which 4 mol% of yttria having an average particle diameter of 0.2 μm was dissolved in solid form was granulated into granules having an average particle diameter of 100 μm, which was calcined at 1200 ° C. 5 g of an organic binder was added to 95 g, and the mixture was pulverized and mixed in a ball mill (volume: 1 liter, balls: 2.5 kg) for 1 hour, and the powder obtained by drying was packed in a rubber mold (diameter 35 mm, thickness 100 mm). It was molded at a pressure of 1 ton / cm ² by a wet cold isostatic press (manufactured by Kobe Steel Co., Ltd., 4 KB × 150 D × 500 L), and sintered at 1350 ° C. to produce a deposition material.

The porosity (%), the mode diameter of pores (μm), and the porosity of the vapor deposition material obtained in Examples 1 to 4 and Comparative Examples 1 to 4.
Table 1 below shows the pore diameter distribution (%) of 1 to 5 μm, the half value range (μm) of the pore diameter distribution curve, the monoclinic crystal ratio (%), and the tetragonal crystal ratio (%).

[0041]

[Table 1]

Each physical property value of the vapor deposition material shown in Table 1 was determined by the following method.

Bulk density: The bulk density of the vapor deposition material was calculated from the weight of a cylindrical sample measured by an electronic balance and the shape and dimensions measured by a micrometer.

Porosity, pore diameter distribution, pore mode diameter, pore volume, half-value range of pore diameter distribution and its maximum value: mercury porosimeter (pore sizer: MIC-9, manufactured by Shimadzu Corporation)
320 type).

The measurements obtained with the mercury porosimeter are:
It is obtained by applying pressure to mercury and injecting mercury into a sample having pores, and obtaining a relationship between the pressure and the integrated volume of mercury that has entered. That is, the pressure for mercury to enter a pore having a certain diameter has a Washburn equation, and by using this equation, the relationship between the injection pressure and the integrated volume of mercury that has penetrated is larger than the diameter of the pore and its diameter. It can be obtained as a relation of the volume of mercury that has entered pores having a diameter. Then, the volume of the intruded mercury is divided by the density of the mercury to show a pore volume larger than the pore diameter.

The relationship between the pore diameter and the pore volume is usually corrected as necessary, for example, the surface tension of mercury, the contact angle, and the mercury head coming from the structure of the measuring device.

The following values are determined from the relationship between the pore diameter obtained by the mercury porosimeter and the cumulative volume of the pores. Furthermore,
The meaning of A to D used in the description of the measured values is shown in FIG.
Explained inside.

Porosity (%): (Total pore volume obtained /
Apparent volume of sample) × 100% Pore mode diameter (B): Curve (A) of change rate (differential value) of relationship between pore diameter and integrated pore volume, ie, maximum peak value in pore diameter distribution curve (A) Corresponding pore diameter (B) Pore diameter distribution and half-value range (C to D) and its maximum value (D): the pore diameter of half the peak height of the pore diameter distribution curve (A) shown in FIG. The peak width is defined as a half value range (C to D) of the pore diameter distribution. Further, the pore diameter of the larger half value range is defined as the maximum value (D).

Average particle size: The average particle size of the powder is measured as follows:
After the powder was preliminarily molded, the surface of the flat surface was observed with a scanning electron microscope and determined by an intercept method.

Similarly, in the case of a vapor deposition material, after a flat surface is formed,
The plane was observed with a scanning electron microscope and determined by the intercept method.

The monoclinic crystal ratio and the tetragonal crystal ratio were obtained by obtaining a diffraction peak with an X-ray diffractometer (manufactured by Mac Science Co., Ltd., M × p ³ VA type) and using the following formulas and formulas 1 and 2. Was.

[0052]

(Equation 1)

[0053]

(Equation 2)

Further, an irradiation test (EB irradiation test 1, measurement conditions: EB output: 0.27 kW and 5 kW) was performed with two types of EBs.
Acceleration voltage 9 kV, current 30 mA, reduced pressure 1-2 × 10 ^-5 T
orr, EB irradiation test 2, measurement condition: acceleration voltage 5 kV,
An electric current of 1 A) was performed to examine the occurrence of cracks in the vapor deposition material. The results are shown in Table 1. Further, the molten state of the vapor deposition material was examined with the EB having an output of 5 kW. The results are also shown in Table 1.

[0055]

According to the method of the present invention, a coating vapor deposition material which does not crack even by EB irradiation can be obtained, and this vapor deposition material is used for heat-resistant coating on components such as aircraft engines.

[Brief description of the drawings]

FIG. 1 is a diagram showing a method for obtaining a half-value range of a pore diameter distribution curve.

[Explanation of symbols]

 A: pore diameter distribution curve B: mode diameter C: minimum value of half value D: maximum value of half value C to D: half value range h: peak height 1 / 2h: peak height 1/2

Claims (6)

[Claims] 1. A sintered body made of zirconia containing a stabilizer, having a monoclinic content of 25 to 70%, a tetragonal content of not more than 3%, and a balance of cubic. And a bulk density of 3.0 to 5.0 g / cm ³ and a porosity of 15 to 5
0%, the mode diameter of the pores is 0.5 to 3 μm and
A vapor deposition material, wherein a pore volume of 1 to 5 μm occupies 90% or more of the total pore volume. 2. The vapor deposition material according to claim 1, wherein the maximum value is 0.85 μm or more in the half value range of the pore diameter distribution curve. 3. The deposition material according to claim 1, wherein the content of the tetragonal crystal is substantially 0%. 4. The vapor deposition material according to claim 1, wherein the particle diameter of the particles is 10 μm or less and no aggregated particles of 20 μm or more are included. 5. A vapor deposition method using the vapor deposition material according to claim 1. 6. The vapor deposition method according to claim 5, wherein the vapor deposition method is an electron beam irradiation type vapor deposition method.