JP3006938B2 - Method of forming titanium nitride-containing composite coating - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a substrate surface containing titanium nitride (hereinafter referred to as TiN) and a compound of titanium (hereinafter referred to as Ti) and another metal or nonmetal by plasma spraying. The present invention relates to a method for forming a TiN-containing composite film.

[0002]

2. Description of the Related Art TiN is known as a highly functional inorganic material, and its use is expanding. That is, TiN is golden, hard, has a high melting point, has good electrical and thermal conductivity, is thermally stable, is stable to acids, and has corrosion resistance. Due to these properties, TiN is added to cermet tools to provide wear resistance,
It is used as a decorative material by improving its oxidation resistance and making use of its golden color. However, conventional TiN
The synthesis method had to use nitrogen (N ² ) gas, and was relatively troublesome. In particular, there is a problem in industrial mass production, which hinders widespread use of TiN.

On the other hand, titanium diboride (hereinafter referred to as TiB ₂ ), which is a kind of diboride, has a high melting point and electrical conductivity, is hard, and has excellent oxidation resistance. For this reason, there has been a strong demand for use as wear-resistant materials, electrode materials, corrosion-resistant materials, heat-resistant materials, and the like. However, it is difficult to obtain a dense molded body by sintering, and TiB ₂ has not been sufficiently used as a material.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for forming a TiN-containing composite film which can easily obtain a TiN-containing composite film which can be used as a material utilizing the function of TiN.

[0005]

According to the present invention, there is provided a method for forming a TiN-containing composite coating, comprising the steps of plasma-spraying Ti powder and other metal or non-metal powder on a substrate surface to form TiN and Ti on the substrate surface. A method for forming a composite film containing a compound with a metal or a nonmetal, comprising mixing a Ti powder so as to be coated with the other metal or nonmetal powder, and subjecting the composite powder to air It is characterized in that plasma spraying is performed on the surface of the substrate, and for example, boron (hereinafter referred to as B) as the other metal or non-metal powder
Powder or carbon (hereinafter, referred to as C) powder, or aluminum or aluminum alloy as a substrate.

FIG. 1 is a schematic view showing an example of a plasma spraying apparatus used in the present invention. In the figure, reference numeral 11 denotes a plasma gun for spraying plasma, and 12 denotes a plasma gun.
1 includes Ti powder and other metal or non-metal powder (for example, B
A power supply, a control device for controlling other devices, a plasma gas supply device for supplying a plasma gas to the plasma gun 11, and a cooling water circulation device. Reference numeral 16 denotes a base (substrate).

[0007] TiN on the surface of the substrate 16 using the above apparatus
The formation of the containing composite film is performed as follows. First, a composite powder composed of Ti powder and B powder was prepared by using FIG. 2 (external view) and FIG.
As shown in the photograph (magnification × 1250) shown in (cross-sectional view) and FIG. 4 schematically showing the photograph, B powder 2 was introduced into uneven surface 1a of Ti powder 1 by mechanofusion treatment of Hosokawa Micron Corporation. And then Ti
The powder 1 is manufactured so as to be covered with the B powder 2, and is put into the powder supply device 12. Next, the substrate 16 is set at a predetermined distance (spraying distance) from the spray nozzle tip 11a of the plasma gun 11. Then, the plasma gas is supplied from the plasma gas supply device 14 and the plasma gas 11 is supplied from the plasma gun 11 to the substrate 16.
At the same time, the composite powder obtained as described above is supplied from the powder supply device 12 into the plasma. The plasma spraying is performed in an atmosphere.

[0008]

The plasma is supplied with a mixed powder obtained by coating a Ti powder 1 with a B powder 2. During the thermal spraying, the B powder 2 moves away from the surface of the Ti powder 1 and the Ti powder 1 is exposed to the atmosphere. Be exposed. Ti exposed to the air tends to form Ti oxides and Ti nitrides due to the presence of oxygen and nitrogen in the air. However, in this case, since the Ti powder 1 is covered with the B powder 2, oxidation of Ti is suppressed, and the change to Ti nitride, particularly TiN, becomes remarkable. On the other hand, Ti undergoes a self-heating reaction with B during plasma spraying and changes to TiB ₂ . Therefore coatings obtained by thermal spraying is a composite film containing TiN and TiB _2. When another metal or non-metal powder is used instead of the B powder, the film contains a compound of Ti and the above-mentioned other metal or non-metal in place of TiB ₂ .

The following analysis proves that Ti undergoes a self-heating reaction with B and changes to TiB ₂ during plasma spraying. That is, the flying speed of the sprayed particles having a particle diameter of 10 to 70 μm is 100 to 300 m / sec,
If the spraying distance is 60 mm, the flight time of the sprayed particles is 0.2 to 0.6 msec, while the self-heating reaction speed is 0.12 m / sec. The diameter is 48 to 144 μm, and the diameter of the sprayed particles used in the present invention is sufficiently in this range.

When the substrate is made of aluminum or an aluminum alloy, heat generated during plasma spraying causes a chemical reaction between the substrate surface and the sprayed particles. For this reason, the interface between the formed film and the substrate is mixed, and the film is bonded to the substrate with a large mechanical strength.

[0011]

As described above, according to the method for forming a TiN-containing composite film of the present invention, a TiN-containing composite film can be formed by a simple method of plasma spraying in air. Therefore, by using this composite film as a material, products utilizing various functions of TiN can be obtained. In particular, it has been extremely difficult to form metal nitrides in the air in the past, and it can be said that the industrial value of the method of the present invention is extremely large.

When B powder is used as a material for coating the Ti powder, a composite film containing TiN and TiB ₂ can be easily formed. Therefore, by using this composite film as a material, not only TiN but also TiB
A product utilizing various functions of ( ₂ ) can be obtained.

When aluminum or an aluminum alloy is used as the substrate, a composite film bonded to the substrate with high mechanical strength can be formed, and a product utilizing the function of wear resistance can be obtained. .

[0014]

[0015]

EXAMPLE A B powder having an average particle size of 0.85 μm was used in an amount of 1.14 to 2.0 mol per mol of Ti powder having a particle size of 10 to 44 μm. The powder was processed into the composite powder shown in FIGS. The composite powder was sprayed on the surface of the substrate 16 by the plasma spraying apparatus shown in FIG. The conditions for plasma spraying were 101 kPa
Under a pressure of (kilopascal), argon is used as the plasma gas, and the supply flow rate is set to 33 to 46 liter / min.
The spraying distance was 60 to 100 mm, the voltage was 31 V at a current of 600 A, or the voltage was 33 V at a current of 800 A, and either the plasma gun or the substrate was moved. The plasma spraying was performed in an air atmosphere.

Table 1 shows the deposition efficiency and the structure of the composite films formed by variously changing the combinations of the above conditions.

[0017]

[Table 1]

In the deposition efficiencies shown in Table 1, x indicates no deposition,
△ indicates low efficiency, and ○ indicates medium to high efficiency. As can be seen from Table 1, a composite film having a substantially dense structure was obtained with good deposition efficiency. FIG. 5 is an optical micrograph (magnification × 100) showing a cross section of the film obtained under the conditions shown in Table 1. In the figure, the lower layer is a substrate, and the upper layer is a composite film. It turns out that it has a very dense structure.

FIG. 6 is an X-ray diffraction diagram of the film obtained under the conditions, and FIG. 7 is an X-ray diffraction diagram of the film obtained under the conditions.
From both figures, it can be seen that the film is a composite film containing TiN and TiB ₂ . The condition of the film is TiB
_Contains a large amount of ₂ .

FIG. 8 is a scanning electron micrograph (magnification × 1100) showing a cross section of the film obtained under the conditions.
FIG. 10 is an analysis diagram of the cross section shown in FIG. 8 by an X-ray microanalyzer. FIG. 9 shows the distribution of Ti, and FIG. 10 shows the distribution of B. Each distribution is indicated by a white dot. FIG.
From this, it can be seen that TiB ₂ is distributed in layers, and that TiN is distributed between the layers. That is, from these figures, it can be seen that TiB ₂ and TiN
Can be seen to be distributed in a layered and uniform manner.

FIG. 11 shows the hardness of the film obtained under the conditions. In the figure, the condition x is a case where neither the plasma gun nor the substrate was moved. Here, load 0.9
The micro Vickers hardness measured at 8N (Newton) is shown. As can be seen from FIG. 11, the resulting coating has a sufficiently high hardness. The reason for the higher hardness under the condition, that is, when the substrate is moved, is considered to be that it contains a large amount of TiB ₂ as shown in FIG.

As described above, according to the method for forming a TiN-containing composite film of the present invention, a TiN-containing composite film can be formed by a simple method of plasma spraying in the air. When B powder is used as the material for coating the Ti powder, a composite film containing TiN and TiB ₂ can be easily formed.

FIG. 12 is an optical microscope photograph showing an interface between a film obtained by using an aluminum alloy as a substrate under the conditions and the substrate. In the figure, the upper layer is a film, and the lower layer is a substrate. FIG. 13 is a scanning electron micrograph (magnification × 3000) of the same part as FIG. 12, and FIGS.
FIG. 4 is a distribution diagram obtained by analyzing a portion indicated by a white line with an EPMA analyzer. FIG. 14 shows that aluminum (hereinafter, abbreviated as Al) and Ti are mixed in the center slightly to the left, and FIG. 15 shows that Al and B are mixed in the center to the left. ing. That is, as can be seen from these figures, the substrate and the film are mixed at the interface.

Table 2 shows the results of a tensile test (JIS H 8666) performed on the film shown in FIG. The tensile test is performed by fixing the substrate on which the film is formed to the test object installation portion of the test apparatus with an adhesive, and pulling the film and the substrate in opposite directions to separate the film and the substrate. In addition, A at the breaking position in the table indicates an adhesive portion, I indicates an interface portion between the substrate and the coating, and L indicates a portion within the coating.

[0025]

[Table 2]

As can be seen from Table 2, the coating of FIG. 12 is bonded to the substrate with sufficient adhesive strength.

When aluminum or an aluminum alloy is used as the substrate as described above, a composite film bonded to the substrate with high mechanical strength can be formed.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of a plasma spraying apparatus used in the method for forming a TiN-containing composite coating of the present invention.

FIG. 2 is a photograph replacing a drawing showing a particle structure,
It is an external view which shows the mixing state of Ti powder and B powder.

FIG. 3 is a photograph replacing a drawing showing a particle structure,
It is sectional drawing which shows the mixing state of Ti powder and B powder.

FIG. 4 is a diagram schematically showing FIG. 3;

FIG. 5 is a photograph replacing a drawing showing a metal structure,
It is sectional drawing of the TiN containing composite film obtained by the conditions.

FIG. 6 is an X-ray diffraction diagram of a TiN-containing composite film obtained under various conditions.

FIG. 7 is an X-ray diffraction diagram of a TiN-containing composite film obtained under various conditions.

FIG. 8 is a photograph replacing a drawing showing a metal structure,
It is sectional drawing of the TiN containing composite film obtained by the conditions.

9 shows a distribution X of Ti in the cross section shown in FIG.
It is a distribution map by a line microanalyzer.

FIG. 10 is a graph showing the distribution of B in the cross section shown in FIG. 8;
It is a distribution map by a line microanalyzer.

FIG. 11 is a diagram showing the hardness of the TiN-containing composite film obtained under the conditions.

FIG. 12 is a photograph instead of a drawing showing a metal structure, and is a cross-sectional view showing an interface between a TiN-containing composite film and a substrate obtained by using an aluminum alloy as the substrate under the conditions.

FIG. 13 is a photograph in place of a drawing showing a metal structure, and is a cross-sectional view showing an interface between a TiN-containing composite film obtained using an aluminum alloy as a substrate and a substrate under the conditions.

FIG. 14 is a photograph instead of a drawing showing an oscilloscope waveform, and is a distribution diagram analyzed by an EPMA analyzer at a white line in FIG. 13;

FIG. 15 is a photograph instead of a drawing showing an oscilloscope waveform, and is a distribution diagram analyzed by an EPMA analyzer at a white line in FIG. 13;

[Explanation of symbols]

 1 Ti powder 2 B powder

────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kiyoshi Urayama 50-42, Yawataen, Yawata-shi, Kyoto (58) Field surveyed (Int.Cl. ⁷ , DB name) C23C 4/10-4/12

Claims (3)

(57) [Claims] 1. A composite coating comprising titanium nitride and a compound of titanium and said other metal or non-metal on the surface of the substrate by plasma spraying titanium powder and another metal or non-metal powder on the surface of the substrate. Forming a titanium powder by mixing the titanium powder with the other metal or non-metal powder, and subjecting the composite powder to plasma spraying on the substrate surface in the air. A method for forming a titanium-containing composite coating. 2. The method for forming a titanium nitride-containing composite film according to claim 1, wherein the other metal or non-metal powder is a boron powder or a carbon powder. 3. The method for forming a titanium nitride-containing composite coating according to claim 1, wherein the substrate is aluminum or an aluminum alloy.