JP2005232496A - Method of manufacturing protective film, and protective film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a protective film by which the protective film having excellent wear resistance and corrosion resistance can be manufactured without heating a substrate to a high temperature, and to provide the protective film. <P>SOLUTION: In this manufacturing method, a protective film is deposited on the substrate by an aerosol deposition method in which powder containing silicon compound (SiC or SiN) is sprayed to the substrate together with carrier gas such as helium at the spraying particle speed of ≥ 800 m/s from very small nozzles. According to the manufacturing method, the protective film having excellent adhesiveness to the substrate can be obtained without exposing the substrate to high temperature. The thickness of the protective film is preferably 0.5-40 μm. The Vickers hardness of the protective film is preferably ≥ 500. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a protective film and a protective film, and more particularly to a method for manufacturing a protective film and a protective film excellent in wear resistance and corrosion resistance.

It is known that the SiC film is useful as a protective film excellent in wear resistance and corrosion resistance. As a method of forming a SiC film on a substrate, a film formation method by a thermal CVD method (chemical vapor deposition method), for example, an organic silicon compound such as CH ₃ SiCl ₃ is thermally decomposed at 1450K to 1650K to form a crystalline material. There is a method of forming a SiC film (Patent Document 1).
Further, as another method, a film formation method by glow discharge decomposition, for example, a gas containing silicon such as SiH ₄ and a hydrocarbon gas such as CH ₄ are mixed and decomposed by glow discharge to form an amorphous material on the substrate. There is a method of forming a SiC film (Patent Documents 2 and 3).

JP-A-11-130565 JP-A-6-97473 Japanese Patent Laid-Open No. 7-22633

However, in the case of film formation using the thermal CVD method, it is necessary to subject the substrate to a high temperature of 1000 ° C. or higher in order to form a SiC film by heating, and it cannot be used for a substrate having no heat resistance.
Further, in the case of film formation using glow discharge decomposition, the obtained SiC film is amorphous, so that the carbon content is less than that of the crystalline SiC film and the Vickers hardness is not large. For this reason, the wear resistance and corrosion resistance are poorer than the crystalline SiC film, and the recent high demands on the wear resistance and corrosion resistance for the protective film for substrates cannot be satisfied.
Therefore, an object of this invention is to provide the method and protective film which can manufacture the protective film which is excellent in abrasion resistance and corrosion resistance, without attaching | subjecting a board | substrate to high temperature.

The manufacturing method of the protective film of this invention is characterized by performing by spraying the powder containing a silicon compound to a board | substrate from a micropore nozzle with carrier gas.
The protective film of the present invention is obtained by the production method of the present invention.

  According to the present invention, a protective film made of a silicon compound can be obtained by spraying a powder containing a silicon compound together with a carrier gas from a microhole nozzle onto the substrate. It can be manufactured without being subjected to high temperatures.

The protective film of the present invention can be obtained by spraying a powder containing a silicon compound together with a carrier gas from a microhole nozzle onto a substrate. Such a protective film forming method is generally called an aerosol deposition method (AD method). By using the AD method, a crystalline silicon compound film can be formed on the substrate without subjecting the substrate to a high temperature. Can be formed on top. In addition, by applying the AD method to film formation using a powder containing a silicon compound, the adhesion between the silicon compound and the substrate can be increased, and a protective film having better adhesion with the substrate can be obtained. it can. As a result, a protective film excellent in wear resistance and corrosion resistance can be easily formed on any substrate.
The silicon compound as the raw material for the protective film is preferably SiC or SiN from the viewpoints of wear resistance and corrosion resistance. In addition, as for the powder of a silicon compound, the protective film at the time of forming into a film from the raw material should just have abrasion resistance and corrosion resistance, and it is not ask | required whether it is crystalline and amorphous.
The particle size of such a silicon compound is preferably 1 μm to 40 μm. When the thickness is less than 1 μm, the collision energy between the particles and the substrate is small, and it is difficult to form a new surface of the particles, and when it exceeds 40 μm, the nozzle is clogged. However, the upper limit of the particle diameter is the particle diameter immediately before film formation when the film forming apparatus for obtaining the protective film is equipped with a crusher or classifier, or a nozzle having a function of a crusher, etc. Therefore, the upper limit of the particle size is not limited.
In addition, titanium carbide, zirconium carbide, hafnium carbide, or the like can be added to the silicon compound for the purpose of increasing the hardness to obtain a mixed powder. In this case, titanium carbide or the like can be contained at 5 to 20% by weight with respect to the entire mixed powder.

  The thickness of the protective film obtained using such a powder containing a silicon compound as a raw material is not particularly limited because it is determined by the use application of the protective film, but is preferably 0.5 μm to 40 μm, and preferably 1 μm to 20 μm is more preferable. If the thickness is less than 0.5 μm, a sufficient effect (abrasion resistance and corrosion resistance) as a protective film cannot be obtained, and if it exceeds 40 μm, the film tends to peel off from the substrate, which is not preferable.

The substrate is preferably a metal plate such as stainless steel, copper, nickel and titanium, or an alloy plate thereof, glass, ceramics or the like. In particular, in the present invention, an excellent protective film can be formed without subjecting the substrate to a high temperature. Therefore, when used for a material having a low heat-resistant temperature or a material used in an environment where corrosion resistance is required, for example, stainless steel. Useful for.
The spraying particle velocity of the powder containing the silicon compound to the substrate is preferably 800 m / s or more, more preferably 900 m / s or more from the viewpoint of adhesion to the substrate. If it is less than 800 m / s, the adhesion of the protective film to the substrate becomes weak, and film formation becomes insufficient. Further, the upper limit of the spray particle speed largely depends on the performance of the film forming apparatus, but the upper limit is not particularly limited.
Such spray particle velocity depends on the type of carrier gas and its flow rate.
As the carrier gas, an inert gas such as helium, argon, or nitrogen can be used, but helium is preferable from the viewpoint of increasing the particle velocity of the silicon compound sprayed onto the substrate. The carrier gas flow rate also depends on the shape of the nozzle used, but is preferably 10 L / min or more, and more preferably 15 L / min or more. If it is less than 10 L / min, the spraying particle speed is less than 800 m / s, which is not preferable. However, since the relationship between the carrier gas flow rate and the sprayed particle velocity differs depending on the type of film forming apparatus to be used, the carrier gas flow rate is not limited to the above flow rate, and the sprayed particle velocity is 800 m / s or more. It may be adjusted as follows.

In the production method of the present invention, the film formation temperature does not have to be a so-called high temperature. Here, “high temperature” generally refers to a temperature that is a reference when determining the heat resistance of a substrate, and is a temperature of 500 ° C. or higher. Therefore, the film formation temperature in the production method of the present invention can be lower than such a temperature, and is preferably 100 ° C. or less, particularly room temperature (25 ° C.) from the viewpoint of economy and operability.
The protective film of the present invention is obtained by the above production method and contains a crystalline silicon compound. Vickers hardness can be used for evaluating the wear resistance of the protective film. As a method for measuring the Vickers hardness, a commonly used method can be applied as it is. For example, a square pyramid indenter having a facing angle of 136 ° is applied with a load of 5 to 50 g, and the protective film is indented. It can be determined by measuring the length. In addition, the corrosion resistance of the protective film can be evaluated by immersing in an acidic solution for a long time, for example, by immersing in an aqueous sulfuric acid solution at 80 ° C. and pH 2 for 200 hours and observing the front and back surfaces. be able to.
The protective film of the present invention preferably has a Vickers hardness of at least 500 from the viewpoint of wear resistance, and more preferably has a Vickers hardness of at least 600. If it is less than 500, sufficient abrasion resistance cannot be obtained, which is not preferable. Such Vickers hardness can be adjusted by film forming conditions such as particle speed, or the kind and amount of powder added to the raw material powder.

With reference to FIG. 1, a film forming apparatus based on the AD method as an example of a manufacturing apparatus that can be used for forming the protective film of the present invention will be described below.
The film forming apparatus is provided with a chamber 1 made of stainless steel. In the chamber 1, a substrate holder 3 that supports a substrate 2, and a nozzle 4 that can inject raw material powder toward the substrate holder 3 are provided. Is provided.
The substrate holder 3 can be driven at a predetermined speed in the XY direction (horizontal plane direction) by a drive mechanism (not shown). In addition, the nozzle 4 and the substrate holder 3 can be moved toward or away from each other and fixed at an arbitrary position by a mechanism (not shown). The nozzle 4 includes an aerosol introduction unit, a throttle unit, and a particle acceleration unit (not shown).

The nozzle 4 is connected to a powder feeder 5 that can supply the raw material powder together with the carrier gas at a constant speed. The powder feeder 5 only needs to have a mechanism capable of supplying the raw material powder at a constant speed. For example, a feeder such as a rotary scraping method equipped with an ejector can be used. A carrier gas cylinder 6 is connected to the powder feeder 5 via a pressure regulator 7 and a mass flow controller 8.
Furthermore, a rotary pump 10 and a mechanical booster pump 11 are connected to the chamber 1 through a filter 9 for collecting dust. The film forming apparatus is provided with a plurality of automatic pumps or manual valves 12 and a plurality of pressure gauges 13 at appropriate locations in order to control the supply amount of the carrier gas and the exhaust in the chamber 1.

  In such a film forming apparatus, first, the substrate 2 is set on the substrate holder 3, and the powder containing the silicon compound is filled in the powder feeder 5. Next, the rotary pump 10 and the mechanical booster pump 11 are operated to evacuate the chamber 1. When the inside of the chamber 1 reaches the ultimate vacuum of 10 Pa or less, the carrier gas is sent from the carrier gas cylinder 6 to the powder feeder 5 at a predetermined flow rate. When the flow rate of the carrier gas reaches a steady value and the flow is stabilized, the powder supply mechanism of the powder feeder 5 is operated. Thereby, an aerosol in which the raw material powder is uniformly dispersed in the carrier gas is generated.

  The aerosol generated in this way is introduced into the aerosol introduction part of the nozzle 4. The introduced aerosol is accelerated when sequentially passing through the throttle portion and the particle accelerating portion of the nozzle 4, and is ejected from the tip of the nozzle 4 toward the substrate 2. The powder containing the silicon compound in the aerosol that collided with the surface of the substrate 2 at high speed is crushed to expose the active new surface, thereby forming a dense protective film having high adhesion on the substrate 2. . At this time, the substrate holder 3 is moved in the X and Y directions by a driving mechanism (not shown) to move the ejection position with respect to the substrate 2 to form a film on the substrate 2 with a predetermined thickness and a predetermined thickness.

Next, the present invention will be further described with reference to examples. In the following examples, the film forming apparatus was used for film formation on a substrate.
However, in Example 1, a substrate holder capable of high speed rotation was used instead of the substrate holder movable in the XY directions.
<Example 1>
The nickel substrate whose surface was polished was set in the substrate holder 3, and the powder feeder 5 was filled with SiC powder (MSC-20 manufactured by Mitsui Toatsu Chemicals). Helium was used as the carrier gas, and the helium flow rate was set to 5 L / min, the distance between the tip of the nozzle 4 and the substrate 2 of 50 mm, and the opening size of the nozzle 4 of 0.5 × 5 mm. A jig having a slit is set under the substrate 2, and an aerosol composed of helium and SiC powder is sprayed from the tip of the nozzle 4 to the substrate 2 in a state where the substrate 2 is rotated at high speed, and the SiC powder collides with the substrate 2. Indentation was formed. Next, the rotation direction of the substrate 2 was reversed, and indentations were formed by the same method. The spray particle velocity of the SiC powder was calculated from the interval between the two indentations. Further, the flow rate of SiC powder was calculated in the same manner as described above by changing the flow rate of helium to 10 L / min, 15 L / min, and 20 L / min.

The calculation method of the spray particle speed of the raw material powder is as follows:
Spray particle velocity = 2π × (nozzle spray position diameter) × (substrate rotation speed) / 60 × (slit-substrate distance) / (indent spacing) / 1000
Can be obtained. Here, the nozzle injection position diameter was set to 290 mm, the substrate rotation speed was set to 3000 rpm, and the slit-substrate distance was set to 16 mm.
The intervals between the indentations obtained were 1.40 mm (5 L / min), 1.12 mm (10 L / min), 0.96 mm (15 L / min), and 0.91 mm (20 L / min), respectively.
FIG. 2 shows the relationship between the sprayed particle velocity calculated in this way and the helium flow rate.

As shown in FIG. 2, as the helium flow rate increased, the sprayed particle velocity of the SiC powder increased. When the flow rate of helium was 10 L / min or more, the sprayed particle speed of the SiC powder exceeded 800 m / s.
Therefore, in this film forming apparatus, a helium flow rate of 10 L / min or more is necessary to obtain a spray particle velocity of 800 m / s.

<Example 2>
A stainless steel substrate (SUS304, the same applies to the following examples) was set on the substrate holder 3, and the powder feeder 5 was filled with SiC powder (MSC-20 manufactured by Mitsui Toatsu Chemicals). Helium is used as carrier gas, helium flow rate of 5 L / min, 50 mm nozzle 4 tip-substrate 2 distance, 0.8 g / min raw material powder supply speed, 0.2 mm / s substrate 2 moving speed, room temperature The film was formed while moving in the XY direction under the conditions. Further, the helium flow rate was changed to 10 and 20 L / min, and the film was formed in the same manner as described above.
When the film was formed at a helium flow rate of 5 L / min, a white SiC powder green compact was formed on the stainless steel substrate. The green compact easily fell off when rubbed with tweezers. On the other hand, when the film was formed at a helium flow rate of 10 and 20 L / min, a dense and high adhesion SiC film was formed on the stainless steel substrate.

<Example 3>
A stainless steel substrate was set in the substrate holder 3, and the powder feeder 5 was filled with SiC powder (MSC-20 manufactured by Mitsui Toatsu Chemicals). Helium is used as a carrier gas, a helium flow rate of 20 L / min, a distance between the tip of the nozzle 4 and the substrate 2 of 50 mm, a raw material powder supply speed of 0.8 g / min, a moving speed of the substrate 2 of 0.2 mm / s, A 0.8 μm SiC film was formed while moving in the XY direction under the conditions (Example A).
The raw material powder is SiC powder (manufactured by IBIDEN), the raw material powder supply speed is 1.5 g / min, the moving speed of the substrate 2 is changed to 0.4 mm / s, and a 0.8 μm SiC film is formed in the same manner as described above. (Example B).
The surface of the SiC film thus obtained was observed with an optical microscope and measured for Vickers hardness. For comparison, a stainless steel substrate (Comparative Example A) on which no SiC film was formed was similarly observed and measured. FIG. 3 shows an optical micrograph (magnification 2000 times), and FIG. 4 shows the results of Vickers hardness measurement.

The Vickers hardness was measured using a Vickers hardness meter (DMS-2LS manufactured by Matsuzawa Seiki Co., Ltd.). Using a regular quadrangular pyramid indenter with a diagonal angle of 136 °, a pyramidal depression was formed on the measurement surface, and the Vickers hardness Hv was determined from the length of the diagonal line according to the following equation. The test load was 50 g and the test temperature was room temperature.
Hv = 0.102F / S = 0.1022Fsin (θ / 2) / d ² = 0.1891 F / d ²
F: Test load (N)
S: surface area of the indentation (mm ² )
d: Average length of indentation diagonal (mm)
θ: Face angle of diamond indenter (°)
The measurement was performed 5 times for the same sample, and the average value was obtained.

As shown in FIG. 3, the surfaces of Examples A and B were dense unlike the rough surface of Comparative Example A, and it was confirmed that a SiC film was formed on the stainless steel substrate.
Moreover, as FIG. 4 shows, the Vickers hardness of Example A and B showed the value of 500 or more, and was 1.8 to 2.1 times of Comparative Example A.
Therefore, by using the AD method, a SiC film having excellent wear resistance could be formed without subjecting the substrate to high temperature.

<Example 4>
A stainless steel substrate was set in the substrate holder 3, and the powder feeder 5 was filled with SiN powder (Ube Industries SNE-10). Helium is used as a carrier gas, a helium flow rate of 20 L / min, a distance between the tip of the nozzle 4 of 50 mm and the substrate 2, a raw material powder supply speed of 0.5 g / min, a moving speed of the substrate 2 of 0.1 mm / s, Under the conditions, a 0.8 μm SiN film was formed while moving in the XY direction.
The surface (Example C) of the SiN film thus obtained was observed with an optical microscope. For comparison, the surface of a stainless steel substrate (Comparative Example B) on which no SiN film was formed was also observed with an optical microscope. FIG. 5 shows an optical micrograph (magnification 2000 times).

As shown in FIG. 5, the surface of Example C was dense unlike the rough surface of Comparative Example B, and it was confirmed that a SiN film was formed on the stainless steel substrate.
Therefore, by using the AD method, it was possible to form a SiN film without being exposed to a high temperature.

<Example 5>
In the same manner as in Example 4, a SiN film was formed on a stainless steel substrate at room temperature. Further, the substrate 2 moving speed was changed to 0.05 mm / s and 0.2 mm / s, and a 0.8 μm SiN film was formed in the same manner as described above. The Vickers hardness of the three types of SiN films thus formed was measured in the same manner as in Example 3. In addition, Example D shows a result at 0.05 mm / s, Example E shows a result at 0.1 mm / s, and Example F shows a result at 0.2 mm / s. For comparison, the Vickers hardness was also measured for a stainless steel substrate on which no SiN film was formed (Comparative Example C). FIG. 6 shows the Vickers hardness measurement results.

As shown in FIG. 6, the Vickers hardness of Examples DF showed the value of 700-939, and was 2.5-3.1 times of Comparative Example C.
Therefore, by using the AD method, it was possible to form a SiN film having excellent wear resistance without subjecting the substrate to a high temperature.

<Example 6>
The SiN film obtained in Example 5 (Examples D to F) and the stainless steel substrate not formed with the SiN film (Comparative Example C) were immersed in a sulfuric acid aqueous solution at 80 ° C. and pH 2 for 200 hours, and the surface before and after the immersion Was observed.
In Comparative Example C, the surface was corroded and the surface unevenness was increased, whereas in Examples D to F, there was no surface corrosion, and no change was observed before and after immersion.
Therefore, by using the AD method, a SiN film excellent in corrosion resistance could be formed.
As described above, according to the present invention, by spraying a powder containing a silicon compound together with a carrier gas from a microporous nozzle onto a substrate, a protective film having excellent wear resistance and corrosion resistance can be easily obtained without subjecting the substrate to a high temperature. Can be manufactured.

It is the schematic which shows an example of the manufacturing apparatus for forming the protective film which concerns on this invention. It is a figure which shows the relationship between the particle velocity and helium flow volume in Example 1. FIG. It is an optical microscope photograph of the surface of the protective film in Example 3, and a stainless steel substrate. It is the Vickers hardness of the protective film and stainless steel substrate in Example 3. It is an optical microscope photograph of the surface of the protective film in Example 4, and a stainless steel board | substrate. It is the Vickers hardness of the protective film and stainless steel substrate in Example 5.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Chamber 2 Board | substrate 3 Board | substrate holder 4 Nozzle 5 Powder feeder 6 Carrier gas cylinder 7 Pressure regulator 8 Mass flow controller 9 Filter 10 Rotary pump 11 Mechanical booster pump 12 Valve 13 Pressure gauge

Claims (10)

  A method for producing a protective film, which is performed by spraying a powder containing a silicon compound together with a carrier gas from a microhole nozzle onto a substrate.   The method for producing a protective film according to claim 1, wherein the silicon compound is SiC or SiN.   The method for producing a protective film according to claim 1 or 2, wherein the sprayed particle velocity of the powder containing the silicon compound is 800 m / s or more.   The manufacturing method of the protective film as described in any one of Claims 1-3 with which spraying to a board | substrate is performed at normal temperature.   The method for producing a protective film according to claim 1, wherein the protective film has a thickness of 0.5 μm to 40 μm.   The method for producing a protective film according to any one of claims 1 to 5, wherein the carrier gas is helium.   A protective film obtained by spraying a powder containing a silicon compound together with a carrier gas from a microporous nozzle onto a substrate.   The protective film according to claim 7, wherein the silicon compound is SiC or SiN.   The protective film according to claim 7 or 8, wherein the Vickers hardness is at least 500.   The protective film according to claim 7, wherein the protective film has a thickness of 0.5 μm to 40 μm.

Images