JPS61266576A - Production of member coated with high-hardness boron nitride - Google Patents

Abstract

PURPOSE:To easily produce a member coated with high-hardness boron nitride at a low temp. by passing an active material in which a hydrogen element and nitrogen element exist and a material to be activated such as boron hydride through electric discharge then introducing the same into the surface of a substrate kept at an adequate temp. CONSTITUTION:The gaseous mixture formed by passing the active material which consists of nitrogen, hydrogen or nitrogen hydride, etc., and in which at least the hydrogen element and nitrogen element exist and the material to be activated which is <=1 kinds among boron hydride, borazine or borazine deriv. through the electric discharge or the gaseous mixture formed by passing the above-mentioned active material through the electric discharge, then mixing the same with the above-mentioned material to be activated is introduced into the surface of the substrate heated to 200-1,500 deg.C preferably under the internal pressure of 0.001-300Torr in a reaction vessel in which the electric discharge is generated by DC, high frequency or microwave. The coating layer of the boron nitride having the excellent density, high hardness and crystallinity is thus formed on the substrate surface and the member coated with the high-hardness boron nitride is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for manufacturing a highly hard boron nitride coated member, which forms a coating layer made of boron nitride on the surface of a substrate by a gas phase reaction method.

(Prior art) Boron nitride can be roughly divided into two types: low-pressure type and high-pressure type. A typical example of low-pressure type is a soft hexagonal crystal that is easily synthesized at normal pressure and has excellent lubricity. There is boron nitride, and a typical example of the high-pressure type is cubic boron nitride, which is hard and dense and synthesized under special conditions of high pressure and high temperature. Among these, cubic boron nitride has the second highest hardness after diamond.

Moreover, diamond has a high affinity for iron, whereas cubic boron nitride has a low affinity for iron, so it is a material that is attracting attention as a tool for cutting iron-based materials, for example. Various methods have been studied to form cubic boron nitride, which has a low affinity for iron and has high hardness, high thermal conductivity, and high electrical insulation, as a coating layer on the surface of a substrate.

Conventionally, methods for forming a WI layer made of boron nitride on the surface of a substrate can be roughly divided into chemical vapor deposition (CVD) and physical vapor deposition (PVD). Alternatively, there is a method in which the reaction is carried out in a reaction gas of a boride such as diporan, ammonia, or drazine and hydrogen.

On the other hand, the latter method includes ion beam deposition, ion implantation, a combination of ion beam deposition and vapor deposition, or a combination of ion implantation.

(Problems to be Solved by the Invention) Among the conventional methods for forming a coating layer made of boron nitride on the surface of a substrate, CVD is a simple thermal gas phase reaction, and therefore soft hexagonal boron nitride is used. There is a problem that only a coating layer consisting of is formed. Among PVD, the ion beam deposition method requires high vacuum, high voltage equipment, ion beam generator, and focusing equipment, and the throughput is small relative to the equipment capacity, making it expensive, and the coating layer formed is expensive. Since the content of cubic boron nitride is small, there is a problem that the hardness is considerably lower than the original cubic boron nitride or that it is difficult to form a dense and thin coating layer. Furthermore, when using the ion implantation method, there are problems in that the processing time is long and it is difficult to form cubic boron nitride. Furthermore, even when various methods are combined, there is a problem that it cannot be put to practical use because the content of cubic boron nitride is small or it is difficult to form a thin film.

The present invention solves the above-mentioned problems, and particularly provides a method for easily forming a coating layer of boron nitride with excellent density, high hardness, and crystallinity on the surface of a substrate at a low temperature. The purpose is to

(Means for Solving the Problems) The present inventors completed the present invention by studying a method of forming a coating layer made of boron nitride in the form of a highly hard and dense film on the surface of a substrate. It is something. i.e. 1
The method for manufacturing a high hardness boron nitride coated member of the present invention includes the presence of at least hydrogen element and nitrogen element selected from nitrogen, hydrogen or nitrogen hydride in a reaction vessel which is discharged by direct current, high frequency or microwave. a mixed gas formed by passing an active substance formed by the active substance and at least one active substance selected from borohydride, borazine or borazine derivatives during discharge;
or at least one of borohydride, borazine or borazine derivatives, through which an active substance selected from nitrogen, hydrogen or nitrogen hydride and containing at least hydrogen element and nitrogen element is passed during discharge. In this method, a mixed gas mixed with a substance to be activated is introduced onto the surface of a substrate heated to 200° C. to 1500° C., and a coating layer made of boron nitride is formed on the surface of the substrate. To specifically explain the method of the present invention, the surface of a substrate made of a sintered body or a composite material including a metal 9 alloy, sintered alloy, and ceramics is subjected to processing such as grinding, polishing, or lapping as necessary. After that, the substrate is washed with a neutral detergent, an organic solvent, etc., and if necessary, steam cleaning, ultrasonic cleaning, or surface etching is performed, and then the substrate is dried and placed in a reaction vessel.

After evacuating the reaction vessel to vacuum, an active substance selected from nitrogen, hydrogen or nitrogen hydride in which at least hydrogen element and nitrogen element are present, and at least one kind of borohydride, borazine or borazine derivative. The substance to be activated is introduced into a reaction vessel and the mixed gas is passed through a discharge by direct current, high frequency or microwave, and then introduced onto the surface of a substrate heated to 200°C to 1500°C. A coating layer consisting of the following can be formed. In addition, after evacuating the reaction vessel, an active substance selected from nitrogen, hydrogen, or hydrogenated nitrogen and containing at least hydrogen element and nitrogen element is introduced into the reaction vessel, and then the active substance is energized by direct current, high frequency, or microwave. The surface of the substrate is heated to 200°C to 1500°C with a mixed gas mixed with at least one active substance selected from borohydride, borazine, or borazine derivatives, which is passed through an electrical discharge and fed into the reaction vessel from a separate route. As a result, a coating layer made of boron nitride can be formed on the surface of the substrate. As used herein, the active substance containing at least hydrogen element and nitrogen element may be at least one type of hydrogenated nitrogen such as ammonia or hydrazine, or a combination of at least one type of hydrogenated nitrogen and hydrogen. It may be a mixed gas, or a mixed gas of at least one type of hydrogenated nitrogen and nitrogen, or a mixed gas of at least one type of hydrogenated nitrogen and hydrogen and nitrogen, or a mixed gas of hydrogen and nitrogen. Boron hydride as an active substance is, for example, diporan (BzH6), tetraporan (
Bs H+ o), Pentaporan 9 (85H9), Pentaporan 11 (Bs) + ■) Hexaporan L O (
B6H+o), hexaporan 12 (86H12), octaporan 12 (88HI2), octaporan l 8
(BeH+s), and borazine or borazine derivatives are borazine or BxNJ with the chemical formula 83 N3 Hb.
Borazine derivatives represented by r are examples of borazine derivatives, such as porannaphthalene (
BsM5Hs).

porazobi7 x nil (86N6HIO), 2, 4-
When feeding boron hydride, borazine or borazine derivatives such as diaminoborazine (83H5H8) into the reaction vessel, if they are gaseous at room temperature and pressure, such as diporan, feed the gaseous diporan as it is. Alternatively, it can also be delivered as a mixed gas of diporane and an inert gas. In addition, borohydrides such as pentaborane or those that are liquid at normal temperature and pressure, such as borazine, can be introduced into the reaction vessel using an inert gas or an active substance as a carrier gas. In addition, substances that are solid at room temperature and normal pressure, such as boron hydride such as decaporane (JoH) and borazine derivatives such as porannaphthalene or poranbiphenyl, are heated to liquid form and then inert gas or activated The substance can be introduced into the reaction vessel as a carrier gas.

When introducing the mixed gas that has passed through the active substance and the activated substance during discharge onto the surface of the substrate, the position of the substrate installed in the reaction vessel must be within the discharge area or outside the discharge area so that the mixed gas that has passed through the discharge It may be placed in a convection region where convection flows toward the discharge port side, or it may be installed in a reaction vessel when a mixed gas mixed with an activated substance is introduced to the substrate surface after the active substance has passed through it during discharge. It is preferable to place the substrate in a convection region outside the discharge region where the mixed gas is convected toward the outlet side rather than in the discharge region. For some reason, A, Q,
Cu, Fe, Ni, Go.

Various metals ranging from low melting point metals to high melting point metals such as St, Mo, W, Ti, Ta, etc., A1 alloy, Cu alloy, Si alloy, stainless steel, heat-resistant alloy °, tool steel, casting, etc. various alloys, or sintered alloys such as sintered high speed steel, cemented carbide, and cermet produced by powder metallurgy, or AR203 ceramics, ZrO2 ceramics, and 5ijNn ceramics.

SiC ceramics, Tic ceramics.

Various sintered bodies including various ceramics such as TiBz ceramics and AIN ceramics, diamond-based high-pressure sintered bodies, and cubic boron nitride-based high-pressure sintered bodies, as well as nine alloys of these metals, and sintered bodies. Plating, CVD on gold, sintered bodies, etc.

Metal 2 alloy or periodic table 4a by PVD.

Carbides, nitrides, oxides, borides of Group 5a and 6a metals, or mutual solid solutions thereof or Azo3, A
Composite materials coated with uN or the like in a single layer or multiple layers, as well as composite materials laminated with at least two or more different materials such as these metal 1 alloys, sintered alloys, and sintered bodies, can be used.

In the method for manufacturing a high-hardness boron nitride-coated member of the present invention, in order to form a boron nitride coated layer with excellent density, high hardness, and crystallinity, the internal pressure in the reaction vessel has a particularly large influence. This internal pressure creates a low-hardness coating layer containing a mixture of soft hexagonal boron nitride or amorphous boron nitride, so the internal pressure inside the reaction vessel is 0.001 Torr ~
It is desirable to set the temperature to 300 Torr, and the discharge energy also greatly affects the properties of the coating layer. for that,
Discharge by microwave is preferable, and the irradiation intensity is IO
The coating layer made of boron nitride coated on the surface of these various substrates, which is preferably W or more and preferably 100W or more, is used in order to effectively exhibit the characteristics of the coating layer and to Due to the need to prevent peeling (it is desirable to have a thickness of mlpm to 30gm), especially when applied to applications where impact is applied, when applied to cutting tools with sharp cutting edges such as drills, or for wear resistance. When applying to extremely small tools such as pen poles and dot bottles, the coating layer thickness should be O0l.
The heating temperature of the substrate when forming the coating layer, which is preferably as thin as 1 to 3 mm, varies depending on the material or shape of the substrate, but it depends on the adhesion between the substrate and the coating layer, the particle size of the coating layer, 500°C to 1100°C based on the deposition rate of the coating layer
is desirable.

(Function) Although the actual theoretical mechanism is not clear in the method of manufacturing a high-hardness boron nitride-coated member of the present invention, gas in which hydrogen and nitrogen elements coexist is passed through a discharge using direct current, high frequency, or microwave. When this occurs, hydrogen and nitrogen in a high energy state in an excited state or an atomic state are generated, and these hydrogen and nitrogen in a high energy state are highly active against active substances such as boron hydride, borazine, or borazine derivatives. Even higher energy is applied, which induces bond dissociation in the active substance, and the active substance is induced into a state similar to radical cleavage, causing rearrangement of atoms during the discharge and forming a B-N bond structure. It is something that continues to form. Although the activated substance is highly chemically reactive and easily reacts with hydrogen and nitrogen in a high energy state, it is easier for the activated substance itself to react if it is passed through an electric discharge.
It becomes easier to form a coating layer of boron nitride with high hardness and excellent crystallinity. Among the active substances, boron compounds containing hydrogen and nitrogen, such as borazine or borazine derivatives, tend to form a coating layer with higher hardness, density, and crystallinity. The method of the present invention enables the formation of a hard boron nitride coating layer easily at low temperatures using a gas phase reaction method, and the coating layer can easily form a dense film-like thin film with fine particles of 1.0 pm or less. Therefore, the adhesion between the coating layer and the substrate is also excellent.

(Example) Example 1 After evacuating the inside of the reaction vessel, 150 mQ/si of hydrogen was added.
Then, borazine 30WIQ/intestinal was supplied with nitrogen and ammonia gas 50mQ/1n as a carrier gas.
n was supplied into the reaction vessel to maintain the internal pressure of the vessel at 5 Torr. A discharge was generated in this reaction vessel using a microwave power of 400 W, and hydrogen, ammonia and borazine were passed through during the discharge. The mixed gas of hydrogen, ammonia and borazine that has passed through this discharge is placed in the discharge area.
The boron nitride was introduced onto the surface of the substrate heated to 000° C. to form a coating layer made of boron nitride. The substrate used here is JIS
l, O,'g on the surface of cemented carbide equivalent to standard 20
It was a composite material with an inner layer of T1CN layer of 0.51 Lm and an outer layer of AiNfi of 0.51 Lm. When the obtained coating material was measured using a scanning electron microscope, X-ray diffraction, and Auger spectroscopy, it was found that the outermost coating layer had a thickness of 2.0 pm and a particle size of 1.0.
It was confirmed that the film was a thin film-like layer corresponding to cubic boron nitride of less than gm. The hardness of the coating layer thus obtained was 4200 kg/++u+2 Vickers hardness.

Example 2 The inside of the reaction vessel was evacuated. Rear hydrogen 200a/uin,
Hydrazine 50 ron/win, nitrogen 20. ,Q
/sin and Diporan 50 J/win were supplied to maintain the internal pressure of the container at 50 Torr. A mixed gas of hydrogen, hydrazine, nitrogen, and diporan was passed through it during discharge using a microwave output of 400 W, and the mixed gas was placed outside the discharge area on the gas outlet side and heated to 1ioo°C.
Ceramics (Si3N4-5%Y2O3-10%A
A coating layer made of boron nitride was formed by introducing boron nitride onto the surface of the substrate of the IN group IO&). The obtained coating material was examined in the same manner as in Example 1, and it was found that the coating layer thickness was OJLm and the particle size was 1.
．． It was confirmed that the film was a thin film-like layer corresponding to cubic boron nitride with a particle size of 0 pm or less.

Example 3 After evacuating the inside of the reaction container, 200 J/in of hydrogen and 50 J/in of ammonia gas were supplied to bring the internal pressure of the container to 0.
The temperature was maintained at 0.05 Torr. After passing this hydrogen and ammonia during discharge with a microwave output of 400 W, a mixed gas mixed with 50 J/sin of borazine using diporane as a carrier gas was placed outside the discharge area on the gas outlet side.
A coating layer made of boron nitride was formed by introducing the boron nitride onto the surface of the substrate heated to 00°C. The substrate used here was made of high-speed steel (SKH-9) with 1. It was a composite material with an inner layer of OBm T i CN layer and an outer layer of 0.5 JLm AiN layer. When the obtained coating material was examined in the same manner as in Example 1, the outermost coating layer had a thickness of 1.5 JLm and a grain size of 1.0.
It was confirmed that it was a film-like thin layer corresponding to cubic boron nitride of pm or less.

(Effects of the Invention) As a result of the above, the method for manufacturing a high-hardness boron nitride-coated member of the present invention is suitable for cutting tools and wear-resistant tools because a hard coating layer made of cubic boron nitride can be easily obtained at low temperatures. It can be applied to

In particular, steel,
It can be used as a cutting tool for various hard materials and difficult-to-cut materials, including cast metals and heat-resistant alloys. In addition, the coating layer is made of boron nitride, which is a dense and thin film with excellent corrosion resistance and chemical stability, so it is suitable for nozzles and mechanical seals.

It can also be used for wear-resistant tools such as valves.
Furthermore, since this is a method for producing a coating material that has a coating layer with high electrical insulation, high thermal conductivity, and high hardness, it has the potential to be applied to functional materials such as electronics materials including semiconductor chips, as well as structural materials. This is an industrially useful manufacturing method.

Claims (2)

[Claims] (1) In a reaction vessel discharged by direct current, high frequency, or microwave, an active substance selected from nitrogen, hydrogen, or nitrogen hydride in which at least hydrogen element and nitrogen element are present, and boron hydride, borazine. or a mixed gas formed by passing at least one activated substance among borazine derivatives during discharge, or an activation formed by the presence of at least hydrogen element and nitrogen element selected from nitrogen, hydrogen, and hydrogenated nitrogen. After passing the substance through the discharge, a mixed gas mixed with at least one active substance selected from borohydride, borazine or borazine derivatives is introduced onto the surface of the substrate heated to 200°C to 1500°C. A method for manufacturing a high hardness boron nitride coated member, which comprises forming a coating layer made of boron nitride on the surface of the substrate. (2) The reaction vessel is 0.001 Torr to 300 Torr
Claim 1 characterized in that the internal pressure is rr.
A method for manufacturing a high hardness boron nitride coated member as described in 2.