JP2801485B2 - Composite and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite formed with a composite film containing hard particles such as diamond particles and cubic boron nitride particles and a method for producing the same, and more particularly to a composite suitable for cutting tools and wear-resistant materials. About.

[0002]

2. Description of the Related Art Conventionally, ceramics have been manufactured by molding and firing predetermined ceramic raw material powder.
Although the excellent properties of the monolithic material have been applied to a wide range of fields, in order to further improve the properties, composite materials having different properties have been developed in recent years.

As a typical composite material, a material in which a fibrous body such as a whisker or special particles (including ultrafine particles) or the like is dispersed in a predetermined material to enhance mechanical properties is known. Attempts have also been made to improve the surface characteristics of a substrate material by forming a film made of a specific ceramic on a predetermined substrate surface.

On the other hand, as a typical method for forming a ceramic film, a vapor phase growth method (CVD method) is known. In this gas phase synthesis method, for example, a plurality of types of reaction gases capable of producing ceramics are introduced into a predetermined reaction furnace in which a substrate is provided, and the reaction gases react with each other in a gas phase to form a substrate surface. A ceramic film.
According to such a film forming method, since it does not contain a sintering aid or the like as compared with ceramics produced by a sintering method, it has a high purity and can bring out the original characteristics of the ceramics. Is being promoted.

[0005] As a specific example, abrasion resistance is improved by depositing diamond, which is a material having high hardness, on a substrate surface such as a cemented carbide or ceramic by a vapor phase growth method. To be applied to wear-resistant parts. In addition, various applications of cubic boron nitride have been advanced as a material having high hardness along with diamond.

[0006]

However, according to the conventional composite coated with a hard film such as diamond or cubic boron nitride, the adhesion between the hard film and the substrate is small, so that the film is easily peeled. However, there is a limitation that the field of use is limited, and, for example, according to the conventional vapor phase growth method, there is a problem that the diamond film growth rate is very slow, so that mass production is lacking and the cost increases.

In the case of forming a ceramic film other than a film of diamond or cubic boron nitride,
It is necessary to grow the film at a high speed, but in that case, there is a problem that a large number of stacking faults are formed in the film, so that the internal stress increases and a crack occurs in the synthesized film.
Moreover, as a characteristic property of the vapor phase growth method, the crystal grows columnar due to the orientation of the crystal at the time of film formation, the strength of the film itself is reduced by abnormal growth particles of the crystal, and the film is damaged by stress in the film. There was a problem such as doing.

[0008]

Means for Solving the Problems As a result of repeated investigations on the above problems, the present inventors produced ceramics on a predetermined substrate surface by a conventional vapor phase growth method, and simultaneously formed diamond particles or diamond particles. By depositing cubic boron nitride particles on a substrate, it is possible to disperse hard particles composed of diamond particles or cubic boron nitride particles in a ceramic film, thereby improving the properties of the metal or ceramic constituting the matrix. I found that I can do it.

That is, the present invention provides a composite comprising, on a substrate surface, hard particles composed of diamond particles or cubic boron nitride particles dispersed in a matrix composed of a metal or ceramic produced by a gas phase method or a mixture thereof. A composite, which is characterized in that the hard particles in the composite film are present more on the surface than inside the composite film, and as a method for producing the composite, a substrate is placed in a reaction furnace. A reaction gas for generating metal or ceramics is introduced to deposit metal or ceramics on the surface of the substrate, and at the same time, the surface of the substrate has more hard particles composed of diamond particles or cubic boron nitride particles than the inside. Characterized in that they are deposited on

[0010]

According to the present invention, the matrix component is precipitated by the reaction gas and at the same time, hard particles such as diamond particles and cubic boron nitride particles are deposited on the surface of the substrate. A composite having a matrix 2 coated with a composite film containing hard particles 3 of diamond particles or cubic boron nitride particles dispersed in a matrix 2 can be obtained. By including the hard particles in the film as described above, the characteristics of the film itself can be improved, and a composite having the characteristics of diamond or cubic boron nitride on its surface can be manufactured at low cost.

Although the hard particles and the substrate have low adhesion due to a large difference in the coefficient of thermal expansion between them, according to the present invention, if more hard particles are present on the surface than inside the film, the composite film itself becomes Abrasion resistance can be improved, and the adhesion of the film to the substrate can be improved by selecting a matrix that approximates the coefficient of thermal expansion of the substrate.

Further, the crystal growth of the matrix component of the film is suppressed by the dispersion of the diamond particles, the formation of huge columnar crystal grains is prevented, and a matrix composed of relatively fine crystal grains can be obtained. This prevents the destruction of the film due to the huge columnar crystal grains.

Further, according to the method of the present invention, since the hard particles are deposited as compared with the film formation by the vapor phase growth method using only the matrix component, the formation speed of the entire film can be increased.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.
FIG. 1 is a schematic layout diagram of a film forming apparatus for producing the composite of the present invention. In the figure, 4 is a reaction furnace, 5 is a substrate, 6 is a reaction gas introduction tube for film formation, 7 is a hard particle introduction tube, 8 is a heater for heating the substrate, and 9 is a holding container for hard particles. The substrate 5 is subjected to gas cooling so as to be 70 ° C. lower than the furnace wall, so that hard particles are efficiently taken into the film by thermophoresis.

According to the present invention, a predetermined substrate 5 is installed in the reaction furnace 4, and a reaction gas for generating a matrix is introduced into the reaction furnace 4 from the gas introduction pipe 6. on the other hand,
Hard particles such as ultrafine diamond particles and cubic boron nitride having a particle size of about 0.01 to 0.1 μm are installed in the container 9, and by intermittently flowing a gas such as hydrogen gas into the container, The hard particles are transported to the reactor 4 through the inlet tube 7. As a carrier gas for transporting the hard particles, hydrogen or a reactive gas for generating a matrix can be used in addition to an inert gas such as nitrogen or Ar.

By setting the temperature of the substrate 5 to a predetermined temperature using the heater 8 and the cooling gas, a matrix is deposited on the surface of the substrate 5 by decomposition and reaction of the reaction gas near the surface of the substrate 5. On the other hand, the hard particles transported into the reactor are deposited on the substrate surface at the same time as the formation of the matrix film, whereby the hard particles are taken into the film. The amount of the hard particles in the film can be changed arbitrarily by increasing the number of intermittent introductions of the carrier gas or changing the flow rate.

For example, as shown in the cross-sectional view of another embodiment of FIG. 3, by gradually increasing the number of intermittent introductions of the carrier gas without introducing the hard particles in the initial stage of film formation, A composite film having a higher content of the hard particles 3 in the matrix 2 is formed on the surface of the substrate 1.

The obtained composite film may be used as it is formed on the surface of the substrate 1, or it may be used as a single composite film by removing the substrate 1 after forming a thick composite film. It is possible.

In the present invention, matrix components such as metals and ceramics containing hard particles dispersed therein include:
Examples include oxides, carbides, nitrides, carbonitrides, borides, and silicides of ceramics such as silicon nitride, silicon carbide, and alumina, and refractory metals such as tungsten and molybdenum, and other metals. They can be used in combination as appropriate.

The hard particles in the composite film according to the present invention are preferably dispersed and contained in the composite film at a ratio of 10 to 80% by volume, preferably 30 to 65% by volume.
In the following, the characteristics of the composite are not significantly improved as compared with the matrix single film, and when the volume is 80% by volume or more, voids are formed in the gaps due to the denseness of the hard particles, and the adhesion decreases.

Hereinafter, the present invention will be described with reference to specific examples. Example 1 In FIG. 2, diamond particles (particle diameter 0.05 to 0.5) were used.
Ar gas was passed through a container 9 containing 1 μm), and the diamond particles were suspended in an inert gas and introduced into the reaction furnace 4. On the other hand, a reaction gas in which methyltrichlorosilane gas was mixed at a concentration of 15% using hydrogen gas as a carrier gas was introduced into the reaction furnace 4 at a flow rate of 5 liter / min. Then, the substrate 5 made of the silicon carbide-based sintered body was heated to 1500 ° C. by the heater 8 to deposit silicon carbide for 15 minutes and simultaneously deposit diamond to produce a composite film having a thickness of 36 μm.

The obtained composite film is composed of 1 diamond particle.
The content was 6% by volume (Sample 1). Further, a film was deposited under the same conditions with the amount of Ar gas flowing through the container 9 being １ ／. As a result, 7% by volume of diamond was contained in the film.
Included (Sample 2). Further, for comparison, a film was formed without depositing diamond to form a silicon carbide film having a thickness of 35 μm (sample 3). When a wear test was performed on the composite obtained as described above by using a pin-on-disk method, the composite of Sample 1 had a wear amount of 30 compared to Sample 3 on which a silicon carbide film was formed. %Diminished.
Further, in the composite of Sample 2, the wear amount was reduced by 6% as compared with Sample 3.

Example 2 As in Example 1, hydrogen gas was passed through a container 9 containing hard particles of diamond particles (50% by volume) and cubic boron nitride particles (50% by volume) to react the hard particles. It was introduced into the furnace 4. On the other hand, a reaction gas obtained by mixing dichlorosilane and ammonia gas at a concentration of 8% with respect to the carrier gas using hydrogen gas as a carrier gas is placed in the reaction furnace 4.
It was introduced at a flow rate of liter / min. Then, the substrate 5 made of the silicon nitride sintered body is heated to 1300 ° C. by the heater 8 to deposit silicon nitride and deposit hard particles at the same time, and to form diamond and cubic boron nitride using silicon nitride having a thickness of 10 μm as a matrix. A composite film containing the hard particles was formed. The resulting film contains 41% by volume of hard particles.
(Sample 4).

When the number of introductions of Ar gas was doubled and the synthesis was performed under the same conditions as above, a composite film containing 64% by volume of hard particles was formed (Sample 5).

When the amount of Ar gas flowing through the container 9 was tripled, a composite film containing 75% by volume of hard particles was formed (Sample 6).

As a comparative example, a silicon nitride single film having a thickness of 10 μm was formed without depositing hard particles (Sample 7).

When a wear test was performed on the composite material obtained as described above in the same manner as in Example 1, the composite of Samples 4 and 5 was compared with Sample 7 of a silicon nitride single film. The wear amount was reduced by 52% and 67%, respectively. Further, the wear amount of Sample 6 was 67 compared to that of Sample 7.
%Diminished.

Example 3 In Example 1, a film containing 5% by volume of diamond was formed at a thickness of 2 μm by changing the amount of Ar gas introduced into the container 9 during the film formation process, and then a diamond film was formed thereon. Is formed at a thickness of 4 μm, and a film containing 60% by volume of diamond is further formed thereon.
It was formed with a thickness of μm (sample 8). When a wear test was performed on the obtained composite in the same manner as in Example 1, the wear amount of Sample 8 was reduced by 75% as compared with Sample 7 of Example 2, which was made of a silicon nitride single film. .

[0029]

As described above, according to the present invention,
By forming a composite film containing diamond particles with excellent thermal conductivity, electrical insulation, hardness, etc. dispersed in a matrix, the characteristics of the film itself, such as abrasion resistance, can be improved, and diamond or cubic A composite having the properties of polycrystalline boron nitride can be manufactured at low cost. Thereby, the wear property can be improved by applying the composite to a cutting tool and various wear-resistant parts. In addition, the characteristics of diamond can be utilized for various components.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one embodiment of the composite of the present invention.

FIG. 2 is a schematic layout view of a film forming apparatus for producing a composite of the present invention.

FIG. 3 is a sectional view showing another embodiment of the composite of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Matrix 3 Hard particles 4 Reactor 5 Substrate 6 Reaction gas introduction tube 7 Hard particle introduction tube 8 Heater 9 Hard particle container

──────────────────────────────────────────────────の Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C23C 16/00-16/56 B23P 15/28 C30B 29/04 B23B 27/14

Claims (2)

(57) [Claims] The present invention relates to a method of coating a substrate surface with a composite film containing diamond particles or hard particles made of cubic boron nitride particles dispersed in a matrix made of a metal or ceramic produced by a gas phase method or a mixture thereof. A composite, wherein the hard particles in the composite film are present more on the surface than on the inside. 2. A substrate is placed in a reaction furnace, and a reaction gas for generating metal or ceramics is introduced to deposit metal or ceramics on the surface of the substrate. At the same time, diamond particles or cubic nitride are deposited on the surface of the substrate. A method for producing a composite, wherein hard particles composed of boron particles are deposited so as to be more on the surface than on the inside.