JPH0849065A - Production of boron nitride coated member - Google Patents

Abstract

PURPOSE:To ensure superior adhesion at the time of producing a member coated with cubic boron nitride or hard boron nitride contg. cubic boron nitride and applied to a sliding member such as the bearing or slider of a tool or other various rotary machines. CONSTITUTION:A middle layer 2 is formed on a substrate 1 and a thin film of cubic boron nitride(CBN) is synthesized on the middle layer to form a CBN layer. Ions of rare gas are implanted into the resultant member to convert each a part of the middle layer 2 and that of the CBN layer 4 into a boundary layer 3. This boundary layer is made of a mixture of the coating material with the material of the middle layer in a state having a gradient compsn. and has superior adhesion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to cubic boron nitride or hard nitriding containing cubic boron nitride, which is applied to wear-resistant mechanical parts such as bearings of various other rotating machines such as tools and sliding members such as slides. The present invention relates to a method for manufacturing a boron-coated member.

[0002]

Cubic Boron Nitride (Cubic Bor)
on Nitride: hereinafter referred to as CBN) has hardness second only to diamond and has low reactivity, and is expected to be applied to wear resistant members. CBN does not originally exist in nature, and granular CBN has been synthesized so far under a high temperature and high pressure environment, and is currently used in sintered products, grindstones, and the like.

However, since CBN is granular, its application range is narrow. Therefore, in order to expand the applicable range, a method of synthesizing CBN as a film is currently being studied.

Examples of the method include a plasma CVD (chemical vapor deposition) method and a PVD (physical vapor deposition) method.
However, the resulting CBN coating has poor adhesion and is very easy to peel from the substrate.

Therefore, as a measure for improving the adhesion of the CBN coating, there is a method of forming the intermediate layer on the substrate and then forming the CBN coating. However, even in this method, although the adhesiveness is improved as compared with the case where the CBN film is directly formed on the substrate, the adhesiveness is not sufficient for practical use.

[0006]

By the way, as described above,
Although CBN can be synthesized as a coating by the PVD method or the CVD method in the conventional technique, the adhesion between the CBN coating and the base material or the intermediate layer is poor, and a coating that can withstand practical use has not yet been formed. is there.

The cause of poor adhesion of the CBN coating is
The large internal stress existing in the CBN coating and the lack of affinity between the CBN coating and the base material or the intermediate layer are mentioned.

An object of the present invention is to solve the above problems of the prior art and to provide a new method for producing a boron nitride coated member in which the adhesion between the CBN coating and the substrate or the intermediate layer is improved.

[0009]

As a structure for achieving the above object, a method for producing a boron nitride coated member according to the present invention is directed to a base material such as tools and various other wear resistant mechanical parts, directly or on the base material. When coating the cubic boron nitride film or the hard boron nitride film containing the cubic boron nitride through the formed intermediate layer, high energy noble gas ions are injected after the thin film synthesis of the cubic boron nitride, thereby, At the boundary between the boron nitride coating and the base material or the intermediate layer formed on the base material, there is a mixed composition of the base material or the intermediate layer and boron nitride, and the component of the base material or the intermediate layer is It is characterized in that a boundary layer having a graded composition which continuously decreases from the material or the intermediate layer side to the coating side is formed.

In implanting the high-energy rare gas ions into the cubic nitrogen film, the acceleration energy of the rare gas ions and the type are selected according to the thickness of the boron nitride film, and the implantation amount of the rare gas ions is 1 ×. 10 ¹⁵ ~ 1 x 10
It is preferable to set it in the range of ¹⁷ (number of ions / cm ² ).

[0011]

As described above, the cause of the insufficient adhesion of the CBN coating in the prior art is the large internal stress existing in the CBN coating and the lack of affinity between the CBN coating and the base material or the intermediate layer.

On the other hand, in the present invention, the adhesion of the CBN coating is improved by forming a boundary layer having a graded composition between the substrate or the intermediate layer and the CBN coating. The causes are as follows.

By forming a boundary layer having a graded composition, the composition in the boundary layer changes continuously,
It is possible to gradually reduce the internal stress in the CBN coating from the CBN coating side to the substrate side or the intermediate layer side.
That is, by introducing an internal stress, which has been concentrated between the CBN film and the base material or the intermediate layer, into the boundary layer, the internal stress is dispersed in the boundary layer, thereby preventing the peeling of the CBN film due to the internal stress. be able to.

Further, since the boundary layer has a graded composition, the affinity between the CBN coating and the boundary layer is larger than the affinity with the base material or the intermediate layer.
The peeling of the N coating can also be suppressed.

The reason why the boundary layer is formed by implanting high energy rare gas ions after the CBN film is formed is as follows.

Generally, when high-energy ions are implanted into a certain substrate, the distribution of the ions in the substrate after implantation shows a normal distribution, the ions do not remain near the surface of the substrate, and there is a certain depth region. Many ions stay in the vicinity of the injection range. Then, in the vicinity of the implantation range, the components of the region are mixed by the collision action and recoil action of the implanted ions and the base material atoms.

Therefore, if the range of implanted ions is set at the interface between the CBN coating and the substrate or the intermediate layer by appropriately selecting the type and energy of the implanted ions, CBN
Implanted ions that have passed through the coating can mix the coating material with the substrate or intermediate layer material near the interface to form a boundary layer having a graded composition.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic cross-sectional view of a boron nitride coated member manufactured by the method of the present invention, and FIG. 2 is a schematic view of a process of forming the boron nitride coated member according to the present invention.

As shown in FIG. 1, the boron nitride coated member of the present embodiment is a high speed tool steel (JIS standard: SKH55).
It is composed of a substrate 1 made of, an intermediate layer 2, a boundary layer 3 having a graded composition, and a CBN layer 4.

Next, referring to FIG. 2, a boron nitride coating member and a method of forming the same will be described. First, the intermediate layer 2 is formed on the base material 1. (See FIG. 2B) As a first example, the intermediate layer 2 is formed by an ion plating method using an HCD (hollow cathode) method to have a thickness of about 3 μm.
The titanium nitride film of was formed.

Specifically, after the substrate 1 shown in FIG. 2 (a) is pretreated by ultrasonic cleaning with an organic solvent (eg, acetone), for example, 1 kV in Ar with a vacuum degree of 0.1 Torr.
Ion bombard for 10 minutes at × 1A, then
HCD gun output: 45V x 400A, substrate temperature: 500
2B is obtained by coating under the conditions of a reaction gas: N ₂ partial pressure of 5 × 10 ⁻⁴ Torr.

Next, as a second example, boron
A B-rich layer having a nitrogen atomic ratio of 1 or more was formed. This can be formed by, for example, an ion deposition method in which irradiation of nitrogen ions or mixed gas ions of nitrogen and a rare gas and boron deposition are simultaneously performed. This method is performed using the apparatus shown in FIG.

FIG. 3 is an enlarged view of the vacuum chamber in the boron nitride coating member forming apparatus used for carrying out the method of the present invention. The apparatus shown in FIG. 3 is applied to the base material 13 attached to the base material holder 12 in the vacuum container 11. On the other hand, at the same time as irradiating nitrogen ions or mixed gas ions 20 of nitrogen and a rare gas from the ion source 14, the metal boron 16 in the evaporation source 15 installed in the lower part of the vacuum container 11 is evaporated by the electron beam 17. Then, the resulting boron vapor 18 is deposited on the substrate 13. Here, 19 is boron vapor 18
It is a monitor for measuring the amount of vapor deposited on the substrate.

As a manufacturing procedure, first, the base material 1 shown in FIG.
Is pre-evacuated to 2 × 10 ⁻⁶ Torr or less.

Next, the nitrogen gas or a mixed gas of nitrogen and a rare gas (for example, argon) supplied to the ion source 14 is ionized in the ion source 14, and the nitrogen ions or the mixed ions of nitrogen and a rare gas 20 are applied to the base material 13. Simultaneously with the irradiation, the boron vapor 18 obtained by evaporating the metallic boron 16 from the evaporation source 15 is vapor-deposited on the base material 13.

At this time, the energy of the mixed gas ions 20 is 2 kev and the evaporation rate of the boron vapor 18 is 1Å / se.
c, the processing time is 5 minutes, and FIG. 2B is obtained. The degree of vacuum at this time is 1 × 10 ⁻⁴ Torr.

As a third example, an intermediate layer 2 consisting of two layers, a titanium nitride layer and a B-rich layer, was formed. Specifically, a titanium nitride film was formed on the base material of FIG. 2A in the same manner as in the first example, and a B-rich layer was formed thereon in the same manner as in the second example.

Next, the CBN layer 4 is formed on the intermediate layer of FIG. 2 (b). The method for forming the CBN layer 4 is basically the same as the procedure for forming the B-rich layer.

Specifically, the irradiation energy of the mixed ions 20 is 0.5 keV and the evaporation rate of the boron vapor 18 is 0.
By setting 4Å / sec, as shown in FIG. 2 (c),
The CBN layer 4 can be formed.

Next, by implanting rare gas ions into the member shown in FIG. 2C, a part of the intermediate layer 2 and the CBN layer 4 is changed to the boundary layer 3. This is done using the device shown in FIG.

FIG. 4 is a schematic view of an apparatus for forming a nitrogen-boron coating member used for carrying out the method of the present invention. In the apparatus, noble gas ions ionized in the ion source 32 in the ion implantation apparatus 31 are ionized at the extraction electrode 33. Withdraw from source 32
Only a predetermined rare gas ion (for example, Ne ⁺ ) is selected by the mass separator 34, the rare gas ion beam is accelerated to a predetermined energy by the accelerating tube 35, and the rare gas ion beam is used as an implantation target by the scanning tube 36. The material 13 shown in FIG. 2 (c) is made to scan the entire area of the material 13 and finally installed in the material holder 12 in the vacuum container 11.
A rare gas ion beam is injected into the.

Specifically, for example, a CBN of about 0.3 μm
For the layer 4, the neon ions are separated into Ne by the mass separator 34.
⁺ (Mass number: 20), the acceleration energy of Ne ⁺ is 200 keV, and the implantation amount is 1 × 10 ¹⁶ (number of ions / c
m ² ), as shown in FIG. 2D, the intermediate layer 2 and the CBN layer 4 are mixed with each other, and the boundary layer 3 having a graded composition is formed.

Here, by changing the acceleration energy of the implanted neon ions according to the thickness of the CBN layer 4, the CBN layers 4 having various thicknesses are formed.
The boundary layer 3 can be formed on the member shown in (c).

Further, the implantation amount of neon ions is 1 × 10 ^15.
If it is less than (the number of ions / cm ² ), the boundary layer 3 is not formed, and if it is more than 1 × 10 ¹⁷ (the number of ions / cm ² ), the CBN layer 4 is destroyed, and the properties such as high hardness of CBN are increased. Will be lost. Therefore, the implantation amount of neon ions needs to be set within the range of 1 × 10 ¹⁵ to 1 × 10 ¹⁷ (number of ions / cm ² ).

The boron nitride coating member having the titanium nitride layer and the B-rich layer as the intermediate layer, which was produced by the above-mentioned example, was subjected to compositional analysis in the depth direction by Auger electron spectroscopy, and as a result, The composition is such that the atomic ratio of boron continuously decreases from the coating side to the intermediate layer side, and the atomic ratio of titanium continuously increases, and the boundary layer 3 is a mixture of the coating material and the intermediate layer material. Further, it was confirmed that it has a graded composition.

FIG. 5 is a critical load relationship diagram showing the results of evaluation of the adhesion of the obtained boron nitride coated member by a scratch test. This is the critical load shown on the vertical axis (the load at which the coating peels). The larger the value, the better the adhesion.

As is clear from FIG. 5, by forming the boundary layer 3, the adhesive force is increased by 4 to 15 times as compared with the case where the boundary layer 3 is not provided, which shows that the adhesive layer has excellent adhesiveness. It was

When implanting high energy rare gas ions, the same effect was obtained even when argon ions, krypton ions, or xenon ions were used as the rare gas ions.

Although the embodiments of the present invention have been briefly described above, the present invention is not limited to the above-mentioned embodiments and can be variously modified within the scope of the technical idea of the present invention. It belongs to the technical scope of the invention.

[0040]

As described above, the boron nitride-coated member manufactured by the method of the present invention has excellent adhesiveness as compared with the conventional one, and is not limited to cutting tools and can be used for various rotary machines. It has an extremely excellent effect as a wear resistant member such as a bearing or a sliding member such as a slide.

Moreover, since the manufacturing method can be carried out by using an extremely simple operation and a low cost device, it is industrially very useful.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a boron nitride-coated member manufactured by the method of the present invention.

2 (a), (b), (c) and (d) are schematic views of a process for forming a boron nitride coated member according to the present invention.

FIG. 3 is an enlarged view of a vacuum chamber in the boron nitride coating member forming apparatus used for carrying out the method of the present invention.

FIG. 4 is a schematic view of a boron nitride coated member forming apparatus used for carrying out the method of the present invention.

FIG. 5 is a relationship diagram of each boron nitride coated member obtained by the method of the present invention and a critical load by a scratch test.

[Explanation of symbols]

 1 Base Material 2 Intermediate Layer 3 Boundary Layer 4 CBN Layer 11 Vacuum Container 12 Base Material Holder 13 Base Material 14 Ion Source 15 Evaporation Source 16 Metal Boron 17 Electron Beam 18 Boron Vapor 19 Monitor 20 Nitrogen + Rare Gas Mixed Ion or Nitrogen Ion 31 Ion implanter 32 Ion source 33 Extraction electrode 34 Mass separator 35 Accelerator tube 36 Scan tube

Claims (2)

[Claims] 1. A cubic boron nitride film or a hard boron nitride film containing cubic boron nitride on a substrate such as a tool and various wear-resistant mechanical parts directly or through an intermediate layer formed on the substrate. Upon coating, high-energy rare gas ions are injected after the thin film synthesis of the cubic boron nitride, thereby forming a base material at the boundary between the boron nitride coating and the base material or the intermediate layer formed on the base material. Alternatively, a boundary layer having a mixed composition of the intermediate layer and boron nitride and having a gradient composition in which the components of the base material or the intermediate layer continuously decrease from the base material or the intermediate layer side to the coating side is formed. A method of manufacturing a boron nitride coated member, comprising: 2. When implanting the high-energy rare gas ions into the cubic nitrogen coating, the acceleration energy of the rare gas ions and the type are selected according to the thickness of the boron nitride coating,
The method for producing a boron nitride-coated member according to claim 1, wherein the implantation amount of the rare gas ions is set in a range of 1 × 10 ¹⁵ to 1 × 10 ¹⁷ (number of ions / cm ² ).