JP2875892B2 - Method of forming cubic boron nitride film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a cubic boron nitride film, and is applied to a tool such as a sliding member which requires wear resistance in general machinery.

[0002]

2. Description of the Related Art As is well known, cubic boron nitride is harder than diamond and has a lower affinity for iron.
Granules synthesized at high temperature and high pressure have been practically used as cutting edges of tools, and in recent years, studies on coating the cutting edges of tools with a cubic boron nitride thin film by the following method have been earnestly made.

(1) Ion plating method: This method uses a vacuum apparatus as shown in FIG. 1 to obtain about 10 ^-3 Torr.
Boron 2 is evaporated from the electron beam evaporation source 1 in a nitrogen atmosphere, and boron vapor and nitrogen are ionized by a discharge between the hot filament 3 and the electrode 4, and the substrate is self-biased by the high-frequency power 5 applied to the substrate 6. 6 is a method of attracting boron ions and nitrogen ions to form a cubic boron nitride film.

(2) Ion beam evaporation method;
Electron beam evaporation source 1 using a vacuum device as shown in FIG.
In this method, boron 2 is evaporated, and nitrogen ions or mixed ions of nitrogen and argon are accelerated by an ion gun 7 to about 0.5 to 1 KV to form cubic boron nitride.

At this time, if the acceleration voltage of the ion gun is set to several KV or more before film formation, boron and nitrogen are implanted into the substrate 6 and at the same time, the elements of the substrate 6 are sputtered and fly out. A mixing layer in which the above-described boron, nitrogen, and substrate elements are mixed is formed. Following this,
When the film is formed under the above-mentioned conditions of cubic boron nitride, a clear interface between the substrate and the cubic boron nitride film disappears, the composition is continuous, the stress concentration is small, and a film with good adhesion is obtained. Can be

[0006]

However, according to the prior art, when a boron nitride film is formed on the surface of a tool material such as high-speed steel or carbide, there are the following problems.

(1) Ion plating method: In this method, a high frequency self-bias voltage is applied to the substrate as shown in FIG. because it parallel to, ions rather goodness around resistance with possible incident perpendicular to the substrate surface, in particular
Productivity in cubic BN thin film formation on complex shaped substrates
high. However, since the self-bias voltage is more limited than the impedance in the vacuum vessel and can not be substantially increased below 1 KV , the ion mixing effect is small. That is, since the depth at which the ions are implanted is small, a thick mixed layer of boron, nitrogen, and the base element cannot be formed, and thus the cubic boron nitride is easily peeled off due to the large internal stress and external force. That is, a sufficient adhesive force cannot be obtained. In FIG. 3, reference numeral 10 denotes a locus of ions.

(2) Ion vapor deposition method: In this method, since a thick mixing layer can be obtained by changing the acceleration voltage Va of the ion gun as described above, a cubic boron nitride film having good adhesion can be obtained. I can .
However, as shown in FIG. 4, the accelerated ions have rectilinearity, and in the case of the substrate 8 having a complicated shape, only the surface perpendicular to the incident direction of the ions can be formed, so that the base material is moved as shown in FIG. 5. Alternatively, it is necessary to move the ion gun so that the ions are perpendicularly incident on the surface of the substrate having a complicated shape. At this time, the surface of the base material on which the ions are obliquely incident is reduced in thickness by sputtering, so that it is necessary to mask 11 as shown in FIG. Therefore, complex shaped substrates
Productivity is low in forming a cubic BN thin film. Further, since the ion gun is still a developing technology, a device capable of extracting a large area with a large current density has not been developed, and the deposition rate of cubic boron nitride itself is lower than that of the ion plating method. small.

The present invention has been made in view of the above circumstances, and provides a method of forming a cubic boron film having high adhesion to a substrate and capable of forming a substrate having a complicated shape with high productivity. The purpose is to:

[0010]

SUMMARY OF THE INVENTION According to the present invention, boron is deposited on a substrate surface by irradiating the substrate surface with nitrogen or argon + nitrogen gas ions at a rate of several kV or more by an ion gun with an increased accelerating voltage. a first step of forming a mixed layer of boron and the substrate element, 0.5 the acceleration voltage of the ion gun
A second step of forming a cubic boron nitride thin film on the mixed layer by performing the same treatment at 1 KV, and depositing boron while ionizing nitrogen or nitrogen + argon gas by discharging between the filament and the electrode. a cubic boron Motomaku forming method, characterized by comprising a third step of forming a cubic boron Motomaku on the thin film Te.

[0011]

According to the present invention, a thick mixing layer is formed by irradiating nitrogen ions or mixed ions of nitrogen and argon at an acceleration voltage of several KV or more while depositing boron initially by an ion deposition method. A thin cubic boron nitride film is formed at an accelerating voltage of about 1 KV to secure adhesion, and it is possible to form a large-area, complex-shaped substrate at high speed.
The coating cubic boron nitride film by a method - a Yi Onpure
By increasing the film thickness , high productivity can be secured.

[0012]

An embodiment of the present invention will be described below.

That is, in the present embodiment, first, boron is vapor-deposited while irradiating nitrogen or argon + nitrogen gas ions with an ion gun 7 having an increased acceleration voltage on the surface of the substrate 8 having a complicated shape. Then, a mixed layer of nitrogen, boron and a substrate element was formed. Subsequently, the acceleration voltage of the ion gun 7 was lowered, and the same processing was performed to form a cubic boron nitride thin film on the mixed layer. Further, while ionizing nitrogen or nitrogen + argon gas by the discharge between the hot filament 3 and the electrode 4, boron was deposited to form a target cubic boron film on the thin film.

Table 1 below shows the film forming conditions and the evaluation results of the films of the comparative example and Examples 1 and 2 of the present invention. However, in Table 1, condition A is mixing condition, condition B is cubic boron nitride film forming condition, condition C is cubic boron nitride film forming condition, V ₁ and V ₂ are ion acceleration voltage [KV],
I ₁ and I ₂ are the ion current density [μA / cm ² ], W is the high frequency power [W], P is the pressure in the vacuum chamber [Torr], and the presence / absence refers to the presence / absence of ion bird (pretreatment).

In Table 1, in Comparative Example 1, the ion plating apparatus shown in FIG. 1 was used, in Comparative Example 2, the ion deposition apparatus shown in FIG. 2 was used, and in Examples 1 and 2 of the present invention, both were used. Using. The evaluation of adhesion was performed by optical microscope observation after film formation and a cutting test. Here, the cutting conditions were as follows: SCM415 having a hardness of Hv170 was used and the cutting speed was 100 m /
At min, the cutting length was 25 mm and the cutting depth was 0.2 mm. The cutting life is the wear width V of the flank of the tool tip.
B was measured successively and shown in comparison with the number of cuts when VB was 0.2 mm. In Comparative Example 1, the coating peeled in a scaly shape during and after the film formation, and a cutting test could not be performed.

On the other hand, in the embodiment of the present invention, even in the cutting test, the interface between the substrate and the cubic boron nitride film, and the cubic boron nitride film formed by ion vapor deposition and the cubic boron nitride film formed by ion plating were formed. No delamination was observed at both interfaces, indicating good adhesion. The cutting life was also substantially the same as that obtained by the ion vapor deposition method of Comparative Example 2, and was about 2.5 times that of the titanium nitride film.

[0017]

As described above in detail, according to the present invention, it is possible to provide a method of forming a cubic boron film having a high adhesion to a substrate and a high productivity even with a substrate having a complicated shape. .

[0018]

[Table 1]

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an ion plating apparatus.

FIG. 2 is an explanatory diagram of an ion deposition apparatus.

FIG. 3 is an explanatory diagram of film formation of a substrate having a complicated shape by ion plating.

FIG. 4 is an explanatory diagram of film formation of a complex-shaped substrate by an ion vapor deposition method.

FIG. 5 is an explanatory diagram of film formation of a complex-shaped substrate by an ion vapor deposition method.

[Explanation of symbols]

Reference numeral 1 denotes an electron beam evaporation source, 2 denotes boron, 3 denotes a hot filament, 4 denotes an electrode, 5 denotes a course of electric power, 6, 8 ... a substrate, 7 ... an ion gun, 9 ... equipotential lines.

Claims (1)

(57) [Claims] 1. A method of mixing nitrogen, boron and a substrate element on a substrate surface by depositing boron while irradiating nitrogen or argon + nitrogen gas ions at several KV or more with an ion gun having an increased accelerating voltage on the substrate surface. A first step of forming a layer and a second step of forming a thin film of cubic boron nitride on the mixed layer by performing the same treatment at an acceleration voltage of the ion gun of 0.5 to 1 KV .
A step, and characterized by comprising a third step of forming a filament and while nitrogen or nitrogen + argon gas by a discharge between the electrodes to ionize, boron cubic on the thin layer by depositing a boron Motomaku Method of forming a cubic boron film.