JP2003027205A - Method for producing thermal spraying material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a chromium-iron based alloy thermal spraying material which has increased pulverizability, and has excellent grain shape. SOLUTION: A chromium-iron based alloy is subjected to heat treatment, and is thereafter subjected to pulverization treatment. The content of chromium in the chromium-iron based alloy is controlled to the range of 60 to 95 mass%, the grain size thereof is controlled to the range of 1 mm to 5 μm, and the heat treatment is performed in an atmosphere of gaseous hydrogen or inert gas. Further, the pulverization treatment is performed by an impact type pulverizer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a chromium-iron based thermal spray material used for a corrosion resistant member.

[0002]

2. Description of the Related Art The thermal spraying method is widely used in the industrial field as a surface modification method for substrates, and is used for aircraft engines, gas turbines for power generation, papermaking for the purpose of imparting corrosion resistance, wear resistance and heat resistance. It is applied to steel rolls and other parts. The thermal spraying method is a method in which a thermal spraying material, which is mainly a powder, is instantaneously melted by a high-temperature heat source, and this is solidified and deposited on the surface of a workpiece to form a film. At this time, as a heat source for melting the spray material, propylene, acetylene, fuel such as kerosene and air, combustion gas type for burning oxygen and argon,
There is a plasma spray type that uses hydrogen, helium, nitrogen, etc., and is used properly according to the purpose of spraying.

The thermal spraying method is (1) faster in film forming speed than other coating methods such as plating, and (2)
Since the frame does not come into direct contact with the base material side, there is little deformation due to heat. (3) Since there is no size restriction of the base material due to the size of the plating tank, etc., it is easy to install on a large area. have. Therefore, the thermal spraying method has been put into practical use for the purpose of anticorrosion and anticorrosion even for large processed products such as steel towers, iron bridges, steel frames, ships, and containers of various chemical industries.

Aluminum, zinc, zinc-
Aluminum alloys, chromium-iron-based alloys, nickel-chromium alloys, Koklari alloys, Niklari alloys, and the like have been put into practical use. Among them, chromium-iron-based alloys are used for the purpose of imparting corrosion resistance. The thermal spray coating of the chromium-iron alloy is also used for the purpose of protecting the battery case from a corrosive active material by forming it on the inner surface of the sodium-sulfur battery anode case.

The conventional thermal spray material of chromium-iron alloy is usually manufactured by crushing and classifying an ingot of chromium-iron alloy as it is.

[0006]

Generally, a vibration mill, an attritor or the like is used as a crusher in the production of the thermal spray material of the iron-chromium alloy, but the thermal spray material of the chromium-iron alloy is used. If the particle size is about several 100 μm, the crushing is easy, but if the particle size is 100 μm or less, the crushing becomes difficult due to the toughness of the chromium-iron alloy. Further, if the pulverization is performed excessively, there is a problem that the inside of the pulverizer is worn and impurities are mixed in the thermal spray material. Furthermore, when a chromium-iron-based thermal spray material having a particle diameter of 100 μm or less is produced by a conventional pulverization method, the particle shape after pulverization tends to be flat,
It was unsuitable for applications in which the fluidity of the powder is important, such as thermal spray materials.

It is an object of the present invention to solve these problems of the prior art, to improve the pulverizability of a chromium-iron based alloy, and to provide a method for producing a thermal spray material having an excellent particle shape and a thermal spray material.

[0008]

The inventor of the present invention arrived at the present invention as a result of intensive studies to solve the above problems. That is, the present invention relates to the following. (1) A method for producing a chromium-iron thermal spray material, which comprises subjecting a chromium-iron alloy to a heat treatment and then a pulverization treatment. (2) The method for producing a chromium-iron based thermal spray material according to (1), wherein the chromium-iron based alloy contains an alloy having a chromium content in the range of 60 to 95 mass%. (3) The chrome-iron alloy is granular and has a particle size of 1 mm to
The method for producing a chromium-iron-based thermal spray material according to (1) or (2), characterized in that it contains grains within a range of 5 μm. (4) The heat treatment of the chromium-iron alloy is performed in a hydrogen gas or inert gas atmosphere (1) to
The method for producing a chromium-iron-based thermal spray material according to any one of (3). (5) The method for producing a chromium-iron based thermal spray material according to (4), wherein the inert gas is argon. (6) The heat treatment of the chromium-iron-based alloy is 500 to 1300.
The method for producing a chromium-iron based thermal spray material according to any one of (1) to (5), which is performed in a temperature range of ° C. (7) The method for producing a chromium-iron-based thermal spray material according to any one of (1) to (6), wherein the pulverization process is performed by an impact pulverizer. (8) The method for producing a chromium-iron based thermal spray material according to (7), wherein the impact type crusher has a wear-resistant member arranged in a liner portion in a comb shape. (9) Any one of the wear-resistant members selected from zirconia, yttria-stabilized zirconia, calcia-stabilized zirconia, magnesia-stabilized zirconia, alumina, alumina zirconia, silicon carbide, silicon nitride, and tungsten carbide-tungsten-cobalt alloy. The method for producing a chromium-iron based thermal spray material according to (8), which is a seed. (10) Chromium according to any one of (1) to (9)
A method for producing a chromium-iron based thermal spray material, wherein the thermal spray material produced by the method for producing an iron based thermal spray material has a particle size distribution within a range of 100 to 5 μm. (11) A thermal spray material produced by the method for producing a chromium-iron based thermal spray material according to any one of (1) to (10),
The apparent density specified by JIS (Z2504) is 2.8-
It is within the range of 3.5 g / cm ^3. A method for producing a chromium-iron-based thermal spray material. (12) The chromium content is in the range of 60 to 95 mass%, the particle size distribution is in the range of 100 to 5 μm, and JIS
Apparent density specified in (Z2504) is 2.8 to 3.5 g.
A chromium-iron-based thermal spray material having a thickness within the range of / cm ³ .

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The method for producing a thermal spray material of the present invention is characterized in that a chrome-iron alloy is heat-treated and then pulverized. The present inventor conducted a study on the crushing treatment of the chromium-iron-based alloy, and the alloy structure was embrittled by subjecting the chrome-iron alloy to a heat treatment, and fine pulverization was made possible by performing the crushing treatment thereafter. It was also found that this pulverization can obtain powder having a shape suitable for thermal spraying.

A chromium-iron alloy is a Cr-Fe alloy,
Cr-Fe-Ni alloy, Cr-Fe-Al alloy, Cr-
Fe-Ni-Al alloys and the like can be exemplified, and further, C, Si, Mn, Cu, Mo, Zn, Ti, Zr, N can be added to these alloys.
An alloy system to which b, Hf, Ta, W, Re, Ge, O, etc. are added is also included.

In the present invention, the chromium content is 60 to
Within the range of 95% by mass, more preferably the chromium content is 7
It is preferable to use a chromium-iron alloy in the range of 0 to 90% by mass. As a result of examining the pulverizability of the chromium-iron alloy after the heat treatment, the present inventor has found that the chrome-iron alloy affects the pulverizability depending on the chromium content. That is, when the chromium content is less than 60% by mass, the toughness of the iron-chromium alloy is increased and the pulverizability is deteriorated, so the effect of improving the pulverizability by the heat treatment is reduced. On the other hand, when the chromium content exceeds 95% by mass, the pulverizability becomes too high and the toughness of the powder is lowered, and the powder has a flat shape not suitable for a thermal spray material.

The present inventor has also found that the carbon concentration contained in the chromium-iron alloy has a close influence on the pulverizability. That is, when the carbon content exceeds 8 mass%, the pulverizability becomes high and the powder has a flat shape which is not suitable for a thermal spray material.

The chromium-iron alloy is preferably granular in consideration of the subsequent heat treatment step and pulverization step, and is preferably in the range of 1 mm to 5 μm, more preferably 300 μm.
It is preferable to contain particles in the range of m to 5 μm.

The heat treatment of the present invention refers to a series of operations in which a chromium-iron based alloy is heated to a constant temperature, kept at the heating temperature for a certain time, and then the chromium-iron based alloy is cooled to room temperature. The rate of temperature increase and the rate of temperature decrease at that time are not particularly limited.

In the present invention, the heat treatment is preferably carried out in a hydrogen gas or inert gas atmosphere in a temperature range of 500 to 1300.degree. When the chromium-iron based alloy of the present invention is heat-treated under these conditions, the alloy undergoes thermal embrittlement or hydrogen embrittlement, which facilitates the production of powder having a shape and particle size suitable for thermal spraying. It is sufficient that the inert gas does not react with the chromium-iron alloy through the heat treatment, and it is preferable to use argon gas, for example. The nitrogen gas is chromium-
Not suitable for use as it reacts with iron-based alloys during heat treatment.

The heat treatment temperature is preferably 500 to 130.
It is carried out within the range of 0 ° C, more preferably within the range of 800 to 1000 ° C. If it is less than 500 ° C, a sufficient brittleness effect cannot be obtained, and the effect of improving the pulverizability is not sufficient. Also 1300 ℃
If it exceeds, the sintering of the chromium-iron alloy itself tends to proceed during the heat treatment, and it becomes difficult to perform the subsequent pulverization treatment.

The holding time at the above heat treatment temperature is preferably in the range of 1 to 10 hours, more preferably 3 to 6 hours.

For the crushing treatment after the heat treatment of the chromium-iron alloy, it is preferable to use an impact crusher.

The impact type pulverizer is a pulverizer having a mechanism in which powder is introduced into the pulverizer by an air stream or the like, and an impact is pulverized by a hammer (grinding hammer) and a liner. There are two types of liner shapes, one with grooves on the inner surface of the liner (Mizo Liner) and one with a smooth shape (Smooth Liner) to improve the pulverizability, but the Mizo Liner is superior to the smooth liner in terms of pulverizability. ing. Generally, a metal material is used for the liner of the impact type crusher, but it has poor wear resistance for crushing the chromium-iron alloy of the present invention. There is a problem that it is worn and impurities are mixed in the thermal spray material.

In the present invention, the wear resistance member, the crushing efficiency and the crushing capacity of the impact crusher are enhanced by using the wear resistant member arranged in a comb shape in the liner portion of the impact crusher, and the thermal spray material is used. Impurities in it can be reduced.

As the material of the wear resistant member, zirconia,
Yttria stabilized zirconia, calcia stabilized zirconia, magnesia stabilized zirconia, aluminum oxide,
Examples of ultrahard materials such as alumina-zirconia, silicon carbide, silicon nitride, tungsten carbide-cobalt, tungsten carbide-cobalt chromium, and tungsten carbide-nickel chromium. Among these, as the wear-resistant member of the impact type crusher of the present invention, it is possible to use a zirconia-based wear-resistant member, for example, zirconia, yttria-stabilized zirconia, calcia-stabilized zirconia, magnesia-stabilized zirconia, or alumina-zirconia. preferable. Further, the material of the liner frame portion for installing the wear resistant member of the impact type crusher of the present invention is preferably a material having a high holding force of the wear resistant member and not largely deformed during the crushing operation, for example, iron-based, stainless steel-based It is preferable to use the above metal.

Further, in the present invention, it is preferable to use the wear resistant member also in the grinding hammer part of the impact type crusher. Also for the wear resistant member used in this part,
As mentioned above, zirconia, yttria-stabilized zirconia,
Examples of ultra-hard materials such as calcia-stabilized zirconia, magnesia-stabilized zirconia, aluminum oxide, alumina-zirconia, silicon carbide, silicon nitride and tungsten carbide-cobalt, tungsten carbide-cobalt chrome, and tungsten carbide-nickel chrome. Among them, a tungsten carbide-based wear resistant member, for example, tungsten carbide-cobalt or zirconia-based wear resistant member,
For example, it is preferable to use yttria-stabilized zirconia. Also, as for the material of the crushing rotor part where the grinding hammer part is installed, it is preferable to use a material that has a high holding force of the wear resistant member and does not significantly deform during the crushing operation. preferable.

FIG. 1 schematically shows a specific example of the impact type crusher of the present invention, but the impact type pulverizer of the present invention is not limited to this.

The powder of the chromium-iron alloy introduced into the crushing chamber 2 from the supply port 1 is introduced into the crushing rotor 4 by the air flow 3, and is crushed by the grinding hammer part 5 and the liner 6 under the impact. The pulverized powder is guided to the classification zone 8 through the outside of the guide ring 7, the fine powder is taken out of the machine through the classifier 9, but the coarse powder is passed through the inside of the guide ring 7 again, It is returned to the crushing rotor 4 and crushed. In this way, the powder that cannot pass through the classifier is repeatedly crushed, and only the fine powder below the set classification point passes through the classifier 9 and is taken out of the machine.

FIG. 2 schematically shows a view from above of the crushing rotor 10 and the liner 11. The wear resistance member 12 is preferably attached to the inner wall of the cylindrical liner 11 used in the impact type crusher of the present invention in a comb shape. The abrasion resistant member 12 attached in a comb shape may be, for example, a simple rectangular parallelepiped shape and has a shape that does not protrude from the upper and lower sides of the liner portion. The wear resistant member 12 having such a shape is attached to the inner wall of the liner at equal intervals. The distance between the wear-resistant members depends on the abrasion of the metal liner frame due to the crushed material (the concave portion of the liner)
It is sufficient to set an interval so that does not progress significantly.

The wear-resistant member 13 attached to the crushing rotor 10 has the crushing rotor 1 on the upper surface of the crushing rotor 10.
It may be arranged in a well-balanced manner so that there is no eccentricity due to 0 rotation.

Abrasion resistant member 12 attached to the inner wall of the liner and abrasion resistant member 13 attached to the crushing rotor
The distance between and is 0.1 to 5 mm, preferably 0.5 to 2 mm at the closest portion.

The method of fixing the wear resistant members 12 and 13 is as follows.
There is no problem if the wear resistant member does not fall off during operation of the crusher, and an adhesive such as an epoxy resin is generally used, but a physical fixing method such as a screw may be adopted. .

As the classification mechanism used in the impact type crusher of the present invention, a commonly used classification mechanism can be used, but a rotary type separator or a mesh type classifier can be preferably used. .

The chromium-iron-based thermal spray material produced according to the present invention is in the range of 100 to 5 μm, preferably 63 to 5 μm.
The range of 5 μm is preferable. When it exceeds 100 μm, the melting in the thermal spray frame is insufficient at the time of thermal spraying, the adhesion efficiency to the base material deteriorates, and the thermal spray coating structure becomes porous, which is not good in terms of corrosion resistance. On the other hand, if the thermal spraying material is less than 5 μm, the fluidity of the thermal spraying powder will be deteriorated, and the film quality of the coating will be non-uniform, and the thermal spraying powder will be easily oxidized, and the film quality of the thermal spraying coating will be deteriorated.

Further, the chromium-iron-based thermal spray material produced by the present invention can obtain a powder having an apparent density defined by JIS (Z2504) within the range of 2.8 to 3.5 g / cm ^3. . As a result, the denseness of the coating at the time of thermal spraying is increased, and a thermal sprayed coating having high corrosion resistance can be formed.

The apparent density measuring method defined in JIS (Z2504) is performed according to the following procedure. The sample is placed in a dry container and kept at 105 ± 5 ° C. for 1 hour, then cooled to room temperature in a desiccator. Take out the sample immediately before the measurement. The sample is poured into a funnel having an orifice with a hole diameter of 2.5 mm, and the flow-out measurement sample is a cup (inner diameter 28 to 30 m).
m, cylindrical shape with a volume of 25 ± 0.05 cm3. ) And pour until it overflows. Immediately after it begins to overflow, stop the flow of the measurement sample, and scrape the powder that has risen above the cup flat with a spatula along the top edge of the cup so as not to give vibration. Then, the side surface of the cup is tapped to sink the powder, the powder adhering to the outside of the cup is removed, and the mass of the powder in the cup is weighed with an accuracy of 0.05 g to calculate the apparent density.

[0033]

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

(Comparative Example 1) Chromium-iron alloy having a chromium content of 75%, particles of 106 μm or less of 39 mass%, 75 μm
An alloy source containing 14% by mass of particles of m or less was crushed without heat treatment. Grinding conditions are chromium-
A metal ball mill (size 180) filled with 1 kg of an iron alloy source and 8.5 kg of S45C, 17φ balls.
(φX180), and crushed for 10 hours after replacement with argon gas. After crushing, take out the crushed product, 106μ
The mass% of particles of m or less and particles of 75 μm or less were measured. The measurement results are shown in Table 1.

Example 1 The same chromium-iron alloy as in Comparative Example 1 having a chromium content of 75% was placed in an atmosphere furnace and heat-treated at 500 ° C. for 4 hours in an argon gas atmosphere.
After cooling, 1 Kg of the chromium-iron alloy source taken out from the atmosphere furnace was replaced with the same material S45C, 17 as in Comparative Example 1.
It was put into a metal ball mill (size 180φX180) filled with 8.5 kg of φ balls, and crushed for 10 hours after replacement with argon gas. After crushing, the crushed product was taken out, and as in Comparative Example 1, particles of 106 μm or less, 75 μm
The mass% of the following grains was measured. The measurement results are shown in Table 1.

(Example 2) The same chromium-iron alloy source as in Example 1 was placed in an atmosphere furnace and heat-treated at 600 ° C for 4 hours in an argon gas atmosphere. The other processing conditions were the same as in Example 1. Table 1 shows the results measured by the same method as in Example 1.

(Example 3) The same chromium-iron alloy source as in Example 1 was placed in an atmosphere furnace and heat-treated at 850 ° C for 4 hours in an argon gas atmosphere. The other processing conditions were the same as in Example 1. Table 1 shows the results measured by the same method as in Example 1.

(Example 4) The same chromium-iron alloy source as in Example 1 was placed in an atmosphere furnace and was placed in an argon gas atmosphere for 9 hours.
Heat treatment was performed at 50 ° C. for 4 hours. The other processing conditions were the same as in Example 1. Table 1 shows the results measured by the same method as in Example 1.

(Embodiment 5) The same chromium-iron alloy source as that used in Embodiment 1 was placed in an atmosphere furnace and placed in an argon gas atmosphere for 1 hour.
Heat treatment was performed at 050 ° C. for 4 hours. The other processing conditions were the same as in Example 1. Table 1 shows the results measured by the same method as in Example 1.

(Example 6) The same chromium-iron alloy source as in Example 1 was placed in an atmosphere furnace and placed in an argon gas atmosphere.
The heat treatment was performed at 200 ° C. for 4 hours. The other processing conditions were the same as in Example 1. Table 1 shows the results measured by the same method as in Example 1.

(Embodiment 7) The same chromium-iron alloy source as in Embodiment 1 is put into an atmosphere furnace and 850 in a hydrogen gas atmosphere.
The heat treatment was performed at 4 ° C. for 4 hours. The other processing conditions were the same as in Example 1. Table 1 shows the results measured by the same method as in Example 1.

(Embodiment 8) The same chromium-iron alloy source as that used in Embodiment 1 is put into an atmosphere furnace and is put in a hydrogen gas atmosphere at 110
Heat treatment was performed at 0 ° C. for 4 hours. The other processing conditions were the same as in Example 1. Table 1 shows the results measured by the same method as in Example 1.

[0043]

[Table 1]

When looking at the results in Table 1, when the comparison was made with the mass% of the ground particles of 106 μm or less, the grinding source, which was 39% by mass before the grinding, was ground without heat treatment (Comparative Example 1). In the case where the heat treatment was carried out, the amount increased to 49% by mass, whereas in the case where the heat treatment according to the present invention (Examples 1 to 8) was performed, the amount was 88 to 97% by mass. This is 1.8 to 2 times that of Comparative Example 1, and a great improvement in pulverizability is obtained.

This tendency can be seen in the comparison of the mass% of the pulverized particles of 75 μm or less, which is 41 without the heat treatment (Comparative Example 1).
In the heat treatment according to the present invention (Examples 1 to 8), the amount is 59 to 71% by mass, which is 1.4 to 1.7 times as high as that of Comparative Example 1. There is.

Example 9 The same chromium-iron alloy source as in Example 1 was used at 1000 ° C. for 2 hours in an argon gas atmosphere.
Heat treatment was performed for an hour. After cooling, an impact type crusher (Hosokawa Micron ACM equipped with the crusher liner of the present invention)
It grind | pulverized by -10).

The metal cylindrical liner frame used in the impact type crusher of the present invention had a thickness of 318 mm and a thickness of 8 mm. The wear-resistant member attached to the inner wall of the liner portion in a comb shape is made of yttria-stabilized zirconia and has a simple rectangular parallelepiped shape that does not protrude from the top and bottom of the liner portion. Specifically, 5mmX8mmX60m
m. 71 such wear resistant members were attached to the inner wall of the liner at equal intervals.

The wear-resistant member attached to the crushing rotor is made of tungsten carbide-cobalt and has a length of 40 mm on the side colliding with the crushed material, a length of 33 mm on the opposite side, a width of 29 mm, and a thickness of 16 mm. used. Four such wear resistant members were attached to the upper surface of the crushing rotor at equal intervals. And the rotation speed of the crushing rotor is 6500r
Grinding was done at pm.

The particles crushed by the impact crusher of the present invention were classified to obtain powder having a particle size range of 38-8 μm.

(Embodiment 10) Heat treatment and pulverization were carried out in the same manner as in Embodiment 9, and then a particle size range of 45 was obtained by classification.
A powder of -10 μm was obtained.

(Embodiment 11) Heat treatment and pulverization were carried out in the same manner as in Embodiment 9, and then a particle size range of 53 was obtained by classification.
A powder of -10 μm was obtained.

Comparative Example 2 The same chromium-iron alloy source as in Example 1 was heat-treated in a hydrogen gas atmosphere at 1000 ° C. for 2 hours. 18φX as grinding media after cooling
It was pulverized for 1 hour by a vibration mill (manufactured by Chuo Kakoki Co., Ltd.) containing 220 pieces of 585L SUS304 rod, and 38-8 μm powder was obtained by a classification operation.

(Comparative Example 3) Heat treatment and pulverization were carried out in the same manner as in Comparative Example 2, and then 45-10 μm by classification operation.
Of powder was obtained.

(Comparative Example 4) After heat treatment was carried out in the same manner as in Comparative Example 2, a 10φ steel ball 35 as a grinding medium was used.
It was crushed for 1.5 hours with an attritor (Mitsui Miike Kakoki Co., Ltd.) containing 0 kg, and classified by 45-10 μm.
Of powder was obtained.

(Comparative Example 5) A 10φ steel ball 3 was used as a grinding medium without heat treatment of a chromium-iron based alloy source.
Grind with an attritor (Mitsui Miike Kakoki Co., Ltd.) containing 50 kg for 1.5 hours, and classify to 53-10 μm.
Of powder was obtained.

Table 2 shows the apparent density (Z2504) values of the powders obtained in Examples 9 to 11 and Comparative Examples 2 to 5. The powder that has been subjected to the heat treatment of the present invention and subjected to impact pulverization is JI
The value of the apparent density of the S metal powder is 2.8 or more. This is due to the rounded shape of the particles as described above, which brings about the effect that the fluidity of the powder during thermal spraying is stable and a uniform film can be obtained. Figure 3
The scanning electron micrograph (SEM) photograph of the powder obtained in Example 10 and the SE of the powder obtained in Comparative Example 3 in FIG.
An M photograph is shown.

[0057]

[Table 2]

Comparative Example 6 The impact type crusher of Example 9
The abrasion resistant member attached in a comb shape inside the liner was crushed using stainless steel. The other conditions were the same as in Example 9 for pulverization.

Table 3 shows the amount of wear of the wear resistant member attached in a comb shape inside the liner portion of the impact type pulverizer used in Example 9 and Comparative Example 6 and the pulverizing performance of the impact type pulverizer. It is a comparative comparison.

[0060]

[Table 3]

By using the impact type crusher of the present invention, the crushing efficiency of the chromium-iron alloy was increased, and the running cost of the impact type crusher was dramatically reduced. Further, the mixture of the abrasion powder of the abrasion resistant member into the pulverized powder is reduced, and the purity of the pulverized powder can be increased.

[0062]

By using the method for producing a chromium-iron based thermal spray material according to the present invention, it has become possible to significantly improve the pulverizability of a chromium-iron based alloy. Further, by using the impact type crusher which has been difficult to put into practical use in the past due to running cost and inclusion of impurities in the production method of the present invention, a significant reduction in running cost and the purity of the thermal spray material produced can be achieved. It has become possible to raise it.

When the impact type crusher of the present invention having a built-in air flow classification function is used inside the crusher, unlike the conventional batch crushing, the temperature of the crushed product is less likely to rise and is less likely to be oxidized. It has a feature that it is not necessary to adjust the atmosphere for preventing oxidation, which is required in the case of batch pulverization, and pulverization in the atmosphere is possible, and the running cost is further reduced.

The thermal spray powder obtained by the present invention is
The roundness brought about the effect that the fluidity of the powder during thermal spraying was stable and a uniform film was obtained.

[Brief description of drawings]

FIG. 1 schematically shows a specific example of an impact type crusher of the present invention.

FIG. 2 schematically shows a top view of a crushing rotor and a liner of the impact crusher of the present invention.

FIG. 3 shows a scanning electron micrograph of the powder obtained in Example 10.

FIG. 4 shows a scanning electron micrograph of the powder obtained in Comparative Example 3.

[Explanation of symbols]

1 supply port 2 crushing room 3 airflow 4 crushing rotor 5 Grinding hammer part 6 liner 7 Guide ring 8 classification zones 9 classifier 10 crushing rotor 11 liner 12 Wear resistant members 13 Wear resistant members 14 motor 15 motor shaft 16 Air entrance

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hisashi Morimoto             Showa Denko Co., Ltd.             Shiojiri Production / Technology Management Department F-term (reference) 4K031 AA02 AA08 AB02 AB08 AB09                       CB01 CB07 CB08 CB18 CB22                       CB32 DA01 DA04

Claims (12)

[Claims] 1. A method for producing a chromium-iron based thermal spray material, which comprises subjecting a chromium-iron based alloy to a heat treatment and then a pulverization treatment. 2. A chromium-iron based alloy having a chromium content of 60-.
The method for producing a chromium-iron based thermal spray material according to claim 1, characterized in that the alloy contains the alloy within a range of 95 mass%. 3. The chromium-iron alloy is granular and has a particle size of 1
The method for producing a chromium-iron-based thermal spray material according to claim 1 or 2, which contains particles within a range of mm to 5 µm. 4. A heat treatment of a chromium-iron alloy is carried out with hydrogen gas,
Alternatively, it is carried out in an inert gas atmosphere, and the method for producing a chromium-iron based thermal spray material according to claim 1. 5. The method for producing a chromium-iron-based thermal spray material according to claim 4, wherein the inert gas is argon. 6. A heat treatment for a chromium-iron-based alloy is performed in the range of 500-1.
It is performed in a temperature range of 300 ° C. 3.
5. The method for producing the chromium-iron based thermal spray material according to any one of 5 above. 7. The chromium-containing alloy according to claim 1, wherein the crushing treatment is carried out by an impact crusher.
Manufacturing method of iron-based thermal spray material. 8. The impact type crusher has abrasion resistant members arranged in a liner portion in a comb shape.
The method for producing a chromium-iron-based thermal spray material according to 1. 9. The wear resistant member is zirconia, yttria stabilized zirconia, calcia stabilized zirconia, magnesia stabilized zirconia, alumina, alumina zirconia,
9. The method for producing a chromium-iron based thermal spray material according to claim 8, wherein the method is any one selected from silicon carbide, silicon nitride, and a tungsten carbide-tungsten carbide alloy. 10. A thermal spray material produced by the method for producing a chromium-iron-based thermal spray material according to claim 1, wherein the particle size distribution is within a range of 100 to 5 μm. A method for producing a chromium-iron based thermal spray material. 11. A thermal spray material produced by the method for producing a chromium-iron-based thermal spray material according to any one of claims 1 to 10 has an apparent density of 2.8 specified in JIS (Z2504).
To 3.5 g / cm ³ in range, a method for producing a chromium-iron based thermal spray material. 12. The chromium content is in the range of 60 to 95 mass%, the particle size distribution is in the range of 100 to 5 μm,
The apparent density specified in JIS (Z2504) is 2.8-
Chromium-iron based thermal spray material having a range of 3.5 g / cm ³ .