JPH04103751A - Formation of tib2 film and tib2 film - Google Patents

Abstract

PURPOSE:To form a TiB2 film obtainable as a film in which TiB2 shall be utilized as various functional materials by mixing Ti powder and B powder in a specified ratio and thermal-spraying this mixed powder on the surface of a substrate in an inert atmosphere. CONSTITUTION:B powder is used in the ratio of 1.1 to 2mol 1mol of Ti powder, and both powder is mixed preferably in such a manner that the Ti powder is coated with the B powder. Next, the above mixed powder is plasma-sprayed on the surface of a substrate to font a TiB2 film on the surface of the substrate. Furthermore, at the time of using aluminum or the allay thereof as the substrate, the TiB2 film formed on the surface of the above substrate is mingled in the boundary between the substrate and the film, and is joined to the substrate with high mechanical strength.

Description

[Detailed description of the invention] (Industrial application field) The present invention is based on TiB2 (titanium boride), which is difficult to mold.
In order to use TiB2 as a material, it is necessary to obtain it as a film.
The present invention relates to a method for forming a film, and in particular to a T i B 2 film formed on a substrate surface made of aluminum or an aluminum alloy (hereinafter collectively referred to as aluminum).

(Prior art and its problems) T I B 2, which is a type of metal boride, has a high melting point, electrical conductivity, hardness, and excellent oxidation resistance. Therefore, there has been a strong desire to use it as a wear-resistant material, an electrode material, a corrosion-resistant material, a heat-resistant material, etc.

However, TIB2 has not been sufficiently utilized as a material because a dense molded body cannot be obtained by sintering.

(Object of the Invention) The present invention provides a method for forming a T i B 2 film that can be obtained as a film to utilize T s B 2 as a variety of functional materials, and in particular a method for forming a T i B 2 film formed on the surface of a substrate made of aluminum. The purpose is to provide two films.

(Means for Achieving the Object) The TiB2 film forming method of the present invention uses B powder at a ratio of 1.1 to 2 moles to 1 mole of Ti powder, mixes both powders, and places the powder in an inert atmosphere. The method is characterized in that the mixed powder is plasma sprayed onto the surface of the substrate to form a TiB2 film on the surface of the substrate, and furthermore, aluminum is used as the substrate. Further, the T iB 2 film of the present invention is a T iB 2 film formed on the surface of a substrate made of aluminum.
The iB 2 coating is characterized by a blended substrate and coating interface.

FIG. 1 is a schematic diagram showing an example of a plasma spraying apparatus used in the present invention. In the figure, 10 is the main body of the apparatus that performs plasma spraying, 20 is an exhaust device, 30 is a cooling device,
40 is a powder supply device, 50 is a gas control device, and 60 is a power source. In the device main body 10, a gun 12 that generates plasma is located in a chamber 11 having a double wall structure.
A substrate 13 and a holder 14 for holding the substrate 13 are installed, and a vacuum gauge 15 is attached to the chamber 11. The exhaust device 20 includes a pipe 21 that has one end communicating with the chamber 11 and the other end open to the atmosphere, and includes, in order from the chamber 11 side, an exhaust cooling device 22, a dust filter 23, a ball valve 24, a Villany vacuum gauge 25, and a leak valve 26. , an oil rotary vacuum pump 27, and an oil mist trap 28 are interposed. In the cooling device 30, a passage for supplying the cooling water is connected to a tank 31 for holding the cooling water, and the passage is connected between the first passage 32 for supplying the cooling water to the gun 12 and the double wall of the chamber 11. a second passage 33 that sends cooling water to the holder 14 for cooling the substrate 13; a third passage 34 that sends cooling water to the holder 14 for cooling the substrate 13; and an exhaust cooling device 2.
The fourth passage 35 is configured to send cooling water to the second passage. In the powder supply device 40, a small vacuum pump 42 and a vacuum gauge 43 for reducing the pressure inside the tank 41 are connected to a tank 41 in which Ti powder and B powder are stored. A powder supply passage 44 also extends from the tank 41, the tip of which is located near the plasma emitting part of the gun 12.

The gas control device 50 includes a first controller 51 that supplies an inert gas for supplying Ti and B powders in a tank 41 through a passage 44, and a second controller that supplies an inert gas used as plasma gas. Control unit 52 and chamber 11
A third control section 53 is provided for supplying an inert gas to create an inert atmosphere inside. Power source 60 is connected to gun 12.

Formation of the TIB2 film on the surface of the substrate 13 using the above apparatus is performed as follows. First, Ti powder and B powder are mixed and then put into the tank 41 of the powder supply device 40. This mixing can be done by simply mixing, but as shown in the photograph shown in Figure 2 and Figure 3 which schematically shows the photograph,
It is preferable to mix the B powder 2 so that it enters the uneven surface 1a of the Ti powder by the mechanofusion process of Hosokawa Micron Corporation, and further coat the Ti powder 1 with the B powder 2. Next, the pump 2 of the exhaust system 20
After the pressure inside the chamber 11 is set to 1 torr or less by the step 7, the third control section 53 supplies an inert gas into the chamber 11 to return the inside of the chamber 11 to a pressure suitable for plasma spraying. Generally, it is 100 to 760 torr. On the other hand, in the powder supply device 40 as well, after the pressure inside the tank 41 is reduced by the pump 42, the first control section 51 supplies inert gas into the tank 41 to fill it. The power source 60 is turned on and the second control unit 52 supplies plasma gas to irradiate the substrate 13 with plasma from the gun 12. At the same time, a mixed powder of Ti and B is supplied from the tank 41 through the passage 44 into the plasma.

Note that, for example, argon gas can be used as the inert gas. In addition, the substrate 1 is the target of plasma irradiation.
It is not limited to a board like 3, but it can also be of other shapes.
As the material of the object, for example, aluminum, steel, titanium, etc. can be used.

(Function) When subjected to plasma spraying, T1 and B undergo a self-heating reaction as shown in the following equation and change to T I B 2, and a T iB 2 film is formed on the substrate surface.

Ti + B -1 → T I B 2 + 539 K
When aluminum is used as the J substrate, the aluminum surface melts due to the heat generated during plasma spraying.

Therefore, the interface between the formed TiB film and the aluminum substrate mixes, and the T I B 2 film is bonded to the aluminum substrate with great mechanical strength.

(Effects of the Invention) According to the method for forming a T I B 2 film of the present invention, a T r B 2 film can be formed on the surface of a substrate. Therefore, by using T i B 2 as a coating material, it is possible to obtain a product that takes advantage of the characteristics of TiB2. In particular, since T IB 2 belongs to the category of having the lowest specific gravity among high-strength materials, a functional composite material with high specific strength can be formed by using aluminum as a base material. As is well known, such materials are highly desired in the field of industrial machinery such as aircraft, automobiles, and robots.

Furthermore, according to the T iB 2 film of the present invention, T i B
Because the interface between the T I B 2 coating and the aluminum substrate surface is intermingled, the T I B 2 coating is bonded to the aluminum substrate with great mechanical strength.

(Example) [Example] B powder with an average particle size of 0.85 μm was used at a ratio of 1.14 moles to 1 mole of Ti powder with a particle size of 38 to 44 μm, and both The powders were mixed as shown in FIGS. 2 and 3. This mixed powder was plasma sprayed onto the surface of a substrate made of aluminum using a plasma spraying apparatus shown in FIG.

The plasma spraying conditions were as follows: argon was used as plasma gas, gas flow rate was 35 g/min, current was 800 A, voltage was 28 V, and spraying distance was 70 mm.

As a result, the TiB film with the cross section shown in FIG. 4 (photo), 13
A is a substrate made of aluminum, and the arrow A side shows the surface of the film. FIG. 5 is an X-ray diffraction diagram of the T r,B 2 film 5. In FIG. 5, a indicates a peak indicating T i B 2, and b indicates a peak indicating Ti. As is clear from FIG. 5, the film obtained in this example is a TiB'' film containing TiB2. Partially enlarged view (photo)
FIG. 7 shows the distribution of B, FIG. 8 shows the distribution of Ti, and FIG. 9 shows the distribution of A and 9. Note that each distribution is indicated by a white dot. From this, it can be seen that B exists in large amounts on the film surface side, and the opposite is true for Ti. This T iB 2 film 5 therefore has a graded composition. FIG. 11 (photo) and FIG. 12 (photo) are distribution maps obtained by performing EP analysis of the portion shown in FIG. 10 (partially enlarged view (photo) of FIG. 4) in the white line area. Figure 11 shows that Ti and B are mixed at interface C, and from this in Figure 12, Ti and B are mixed at interface C! It can be seen that it is mixed with Figure 13 (photo) shows T i in Figure 10.
It is an enlarged view showing the interface between the B2 film 5 and the surface of the aluminum substrate 13a.
Figure 6 (photo) is an analysis diagram of the part shown in Figure 13 using an X-ray microanalyzer, Figure 14 shows the distribution of B, Figure 15 shows the distribution of Ti, and Figure 16 shows the distribution of A, The distribution of Q is shown.

Note that each distribution is indicated by a white dot. It can be seen from this that Ti and B are mixed with Ajll at the interface.

As described above, according to this embodiment, since Ti powder and B powder are mixed as shown in FIGS. 2 and 3 and plasma sprayed, it is possible to obtain a TlB2 film 5 with a dense structure without bubbles. did it. Moreover, since the spraying was performed on the surface of the substrate 13a made of aluminum, TiB was strongly bonded to the substrate 13a.
2 film 5 could be obtained.

Second Example Particle size of 5 to 1 mole of Ti powder with particle size of 10 to 44 μm
200 μm B powder was used in a ratio of 2 moles, and both powders were mixed by simply mixing. This mixed powder was plasma sprayed onto the surface of a steel substrate using a plasma spraying apparatus shown in FIG. The conditions for plasma spraying are: argon is used as the plasma gas, gas flow rate is 35N/win, and current is 60%.
0-80OA.

The voltage was 28V and the spraying distance was 70mm.

As a result, a TiB2 film having a cross section shown in FIG. 17 (photo) was obtained. In FIG. 17, 5a is T I B 2
The film 13b is a steel substrate. Figure 18 shows T IB
2 is an X-ray diffraction diagram of the No. 2 coating 5a. ] In Figure 8,
a is a peak indicating T r B 2, and b is a peak indicating Ti. As is clear from FIG. 18, the film obtained in this example is a T I B 2 film containing T iB 2 .

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an example of a plasma spraying apparatus used in the TiB 2 film forming method of the present invention, and FIG. 2 is a photograph in place of a drawing to show the mixed state of T1 powder and B powder.
FIG. 3 is a diagram schematically showing FIG. 2, FIG. 4 is a photograph replacing a drawing showing the cross section of the TiB2 film obtained in the first example, and FIG. 5 is a diagram showing the T i B 2 of FIG. 4. X-ray diffraction diagram of the film, Figure 6 is a photograph that is a partial enlargement of Figure 4, and Figures 7 to 9 are photographs that replace the analysis of the part shown in Figure 6 using an X-ray microanalyzer. FIG. 7 shows the distribution of B, FIG. 8 shows the distribution of T1, and FIG. 9 shows the distribution of Ag. Figure 10 is a photograph that replaces a drawing that partially enlarges Figure 4; Figures 11 and 12 are photographs that replace a distribution map obtained by EP analysis of the area shown in Figure 10 with white lines;
Figure 13 is a photograph that replaces the enlarged view of the interface between the eight Ti films and the aluminum substrate in Figure 10, and Figures 14 to 16 are X-ray microanalyzer analysis diagrams of the portion shown in Figure 13. This is a replacement photo, and Figure 14 is B
15 shows the distribution of Ti, and FIG. 16 shows the distribution of Ag. FIG. 17 shows T i B obtained in the second example.
2. A photograph in place of a drawing showing the cross section of the film, Figure 18 is
FIG. 7 is an X-ray diffraction diagram of the T iB 2 film of FIG. 7; 】−・・・
・Ti powder, 2...B powder, 5.5a...TI
B 2 film, 13a...aluminum substrate, 13b...
...Steel substrate patent applicant Japan Aluminum Industry Co., Ltd. Agency of Industrial Science and Technology Figure 2 Figure 5 a TiB2 Tl Figure 6-〇, r Uno Figure 3 Th ■ l No. 1-1 S I No.;i, 1tsu1 Procedural amendment (method) December 12, 1990

Claims (3)

[Claims] (1) B powder is used at a ratio of 1.1 to 2 moles per mole of Ti powder, both powders are mixed, and the mixed powder is plasma sprayed onto the surface of the substrate in an inert atmosphere to coat the surface of the substrate with TiB powder.
A method for forming a TiB_2 film, characterized by forming a _2 film. (2) The method for forming a TiB_2 film according to claim 1, in which aluminum or an aluminum alloy is used as the substrate. (3) A TiB_2 film formed on the surface of a substrate made of aluminum or aluminum alloy, characterized in that the interface between the substrate and the film is mixed.
2 membranes.