JP2979921B2 - Ultra thin film laminate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface of a hard base material such as a cutting tool or a wear-resistant tool, or a surface of an electric / electronic part, a sliding part or a machine part for improving abrasion resistance and surface protection function. The present invention relates to an ultra-thin film laminate formed on a substrate.

[0002]

2. Description of the Related Art Conventionally, in order to improve abrasion resistance and surface protection function, the surface of a hard base material such as a cutting tool or abrasion resistant tool made of WC-based cemented carbide, cermet, ceramics, high-speed steel, etc. is conventionally used. , As a hard coating layer, PVD method or C
A single layer or multiple layers of carbides, nitrides, carbonitrides or oxides of Al, Ti, Hf, and Zr are formed by the VD method.

For the purpose of improving the oxidation resistance of the hard coating layer, for example, as disclosed in Japanese Patent Publication No. 4-53642, the above-mentioned Ti carbon / nitride is used as a hard coating layer of a cutting tool. Is known to form a complex carbide solid solution, a complex nitride solid solution, and a complex carbonitride solid solution of Ti and Al, respectively.

[0004] Furthermore, in the Journal of the Japan Institute of Metals, Vol. 57, No. 8, (1993) 919-925, it has been reported that in a Ti-Al-N-based hard coating layer, the oxidation resistance as well as the increase in the solid solubility of Al-N is increased. Although improved, the solid solubility of Al-N is 75 mol%
It is reported that the hardness is reduced when the ratio exceeds.

However, in the above-mentioned conventional hard coating layers, the properties inherent to the material constituting the coating layer directly determine the properties of the entire coating layer, and are used for cutting tools such as end mills and indexable inserts and wear-resistant tools. In this case, it is difficult to achieve both abrasion resistance and oxidation resistance. In particular, in high-speed cutting and cutting of high-hardness materials, the use of a coating layer material that emphasizes oxidation resistance has a problem in that wear resistance is reduced. .

On the other hand, as a means for achieving high curing of the coating layer, there is a method of laminating a thin film of nm order to increase the hardness by the effect of lattice strain energy at the interface. Instead, other properties required for cutting tools and wear-resistant tools are sacrificed, and there is a drawback that the effect is particularly poor with respect to oxidation resistance.

In addition to the above-mentioned cutting tools and wear-resistant tools, abrasion-resistant films and protective films are conventionally formed on the surfaces of electric / electronic parts, sliding parts and mechanical parts, for example, magnetic tapes, floppy disks or magnetic disks. Co-Ni, Co-P, γ as a wear-resistant film on the surface of a high-density recording medium such as
-Fe ₂ O ₃ is coated, or an oxide, nitride, carbon film or the like of silicon dioxide, silicon nitride, aluminum oxide or the like with a thickness of about 80 nm is coated as a protective film.

However, with the recent progress of high-density and large-capacity recording, the protective film is required to be further reduced in thickness, and the film thickness is required to be 50 nm or less. If the thickness of the conventional protective film is reduced to 50 nm or less, the abrasion resistance and corrosion resistance become insufficient, and there is a problem that the above requirements cannot be sufficiently satisfied.

Therefore, the present invention solves the above problems,
Ultra-thin laminates that improve the wear resistance of the hard coating layer on cutting tools and wear-resistant tools, and also have excellent properties as wear-resistant and protective films on the surfaces of electrical and electronic parts, sliding parts, and machine parts It is intended to provide.

[0010]

In order to solve the above-mentioned problems, the present invention relates to Ti _x Al _1-x N and Ti _y Al _1-y N (0 ≦ x <
Two types of compounds, 0.5 and 0.5 <y ≦ 1), were alternately and repeatedly laminated to adopt a structure in which the overall composition of the laminate became stoichiometrically aluminum-rich. .

The ultra-thin film laminate of the present invention has a repetitive lamination period of 0.5 nm to 20 nm and an overall film thickness of 0.1 nm.
The most preferable effect can be obtained by setting the thickness to 5 μm to 10 μm. When used as a coating layer of a cutting tip, a drill or an end mill, the ultra-thin film laminate is formed of WC
Coating on the surface of hard base material such as base cemented carbide, cermet, ceramics, high-speed steel, etc.

Here, the repetitive lamination cycle means, for example, as shown in FIG. 1, when two types of compounds A and B are repeatedly laminated alternately, the thickness (t ₁ ) of the compound A and the compound B
(T ₁ + t ₂ = λ) with its thickness (t ₂ ).

In FIG. 1, reference numeral 1 denotes an ultra-thin film laminate, and reference numeral 2 denotes a substrate.

When the above-mentioned ultra-thin film laminate is coated on the surface of a substrate, an interface layer 3 is provided between the ultra-thin film laminate 1 and the substrate 2 as shown in FIG. Law table IVa
1 selected from the group consisting of group III, group Va, group VIa metal elements
A film thickness of at least one kind of a compound comprising a combination of at least one kind of element and at least one kind of C and N;
It is preferably 5 μm.

[0015] The use of the ultra-thin film laminate may be
When making a wear-resistant film or a protective film on the surface of electronic parts, sliding parts, and mechanical parts, the total thickness of electric and electronic parts is 5 nm.
It is preferable that the total film thickness is 0.1 μm to 10 μm for sliding parts and mechanical parts.

As a method of forming the above-mentioned ultra thin film laminate, there are a CVD method and a PVD method. In particular, the PVD method can form a ceramic film having a remarkably high melting point and hardness at a temperature of 500 ° C. or less. Therefore, it is a preferable manufacturing method in that the strength of the base material can be easily maintained and the influence of atomic diffusion in the interface layer between the laminates can be reduced.

[0017]

The ultra-thin film laminate according to the present invention uses two kinds of compounds composed of Ti, Al and N to form a stoichiometrically aluminum-rich Ti _x Al ₁ -xN (0 ≦ x
<0.5), and stoichiometric titanium-rich Ti _y
Al _1-y N (0.5 <y ≦ 1) is alternately and repeatedly laminated to form an aluminum-rich Ti-Al-N compound having excellent oxidation resistance as a whole thin film composition.

By adopting such a structure including a stoichiometrically titanium-rich ultra-thin film layer, a decrease in hardness caused by a thin film of an aluminum-rich Ti—Al—N compound alone is suppressed. It is possible to achieve both high hardness and oxidation resistance that cannot be achieved. By utilizing this characteristic, when used as a coating layer of a cutting tool or a wear-resistant tool, the wear life of the tool can be greatly extended.

In addition, two different kinds of compounds are alternately used in 0.1.
When laminated with an extremely thin film thickness of 5 nm to 20 nm, the Vickers hardness is 3500 kgf / mm under a load of 25 gf.
High hardness, which cannot be obtained with a thin film of a compound of ² or more alone, can be realized, and excellent wear resistance is exhibited.

This is because, when the repetition lamination period is set to 20 nm or less, the atoms forming the interface among the atoms constituting the crystal, that is, the atoms in contact with the interface increase, and are caused by the interface rather than the characteristics inherent to the substance. It is considered that the characteristics are remarkable, and the hardness increases due to the effect of lattice strain energy at the interface. On the other hand, when the repetition lamination cycle is 0.5
In the case where the thickness is less than 10 nm, the layer becomes a mixed layer of the laminated materials due to the influence of interdiffusion at the interface. In any case, a remarkable hardness increasing effect by lamination cannot be obtained.

In the ultra-thin film laminate of the present invention, the adhesive strength of the ultra-thin film laminate to the substrate can be improved by interposing an interface layer between the two rather than directly forming the substrate on the substrate surface. . This is because by providing an interfacial layer with intermediate properties between the base material and the ultra-thin film laminate, which have greatly different properties, the properties change continuously, and the effect of reducing the residual stress of the film etc. Is expected. The effect of the interface layer is not improved when the film thickness is less than 0.05 μm. Conversely, when the film thickness exceeds 5 μm, no further improvement in the adhesion strength is observed. Can be demonstrated.

The same effect as that described above is obtained by using Ti
-Nitride of Al alloy other than Al-based, for example, (AlZr)
N, (AlNb) N, (AlHf) N, etc. can also be obtained by laminating a film with a changed alloy composition.
In the present invention, T is obtained from a good balance between oxidation resistance and hardness.
i-Al nitride is adopted.

[0023]

Next, a description will be given of an embodiment performed to see the effect of the present invention. In the following examples, when an ultra-thin film laminate is formed, the measurement of the lamination cycle on the order of nm is performed by observation with a transmission electron microscope (TEM) and small-angle X-ray analysis. In addition, for a long-period laminated structure, the lamination period can be measured by a high-resolution scanning electron microscope.

<Example 1> A plurality of cutting tips made of cemented carbide having a composition of JIS standard P30 and a shape of JIS SNG432 were prepared as a base material, and the surface thereof was subjected to ion plating by vacuum arc discharge. Was formed. Here, the cutting insert samples according to the examples of the present invention were No. 1 to No. 26.

[0025]

[Table 1]

FIG. 3 shows a method of manufacturing a cutting chip sample. The sample is formed by forming a plurality of T chips inside the film forming apparatus 4.
The targets 5 and 6 of the i-Al compound are arranged, and the cutting tip 8 is mounted on the substrate holder 7 which rotates between the targets about the center point of the target. By adjusting one or both of the discharge currents (evaporation amount of the target material), the repeating lamination cycle was adjusted.

First, the degree of vacuum in the film forming apparatus 4 is set to 1
0 ^-5 Torr, Ar gas was introduced into the atmosphere, the temperature was raised to 500 ° C. while maintaining a vacuum of 10 ⁻² Torr, and a voltage of −1000 V was applied to the cutting tip 8 for cleaning. Ar gas was exhausted. Next, the film forming apparatus 4
One or several kinds of N ₂ gas and CH ₄ gas are controlled at 200 cc / m by time control according to the rotation of the substrate.
in, and a vacuum arc discharge is performed in this state to vaporize and ionize the target elements 5, 6 of the metal elements of the groups IVa, Va, and VIa of the periodic table and the Ti-Al compound. When the rotating cutting tip passed in front of the target, a compound layer of the target material and C and N in the introduced gas was formed on the cutting tip.

For comparison with the samples of the above-mentioned examples, cutting tips having a hard coating having a conventional structure shown as samples 27 to 30 in Table 1 were prepared. In this case, samples 27 to 29
Is a single hard coating on the surface of a cutting tip having the same composition and shape as described above by an ion plating method using vacuum arc discharge using a normal film forming apparatus, and a sample 30 is formed by a normal CVD method. Fabricated by forming layers.

In this example, a continuous cutting test and an intermittent cutting test were performed on the various cutting insert samples prepared as described above under the conditions shown in Table 2 below, and the flank wear width of the cutting edge was measured. Table 3 shows the results of each cutting test.

[0030]

[Table 2]

[0031]

[Table 3]

From the results shown in Table 3, among the samples of the conventional structure, the samples 27 to 29 in which the hard coating layer was formed by the PVD method were inferior in wear resistance, and the sample 30 formed by the CVD method was inferior in the toughness of the base material. Decreased in fracture resistance. On the other hand, Samples 1 to 24 (excluding Sample 8) according to the present invention have excellent wear resistance in both continuous cutting and interrupted cutting,
Further, the toughness of the base material was maintained, and excellent fracture resistance was exhibited.

From the results of Samples 1 to 7, the optimum laminating cycle when the ultra-thin film laminate is applied to a cutting tool is 0.5 nm to 20 nm. From the test results, it is clear that an appropriate thickness of the interface layer is 0.05 μm to 5 μm.

In addition, from the test results of Samples 9 to 12, the total thickness of the ultra-thin film laminate was 0.5 μm to 10 μm
Is suitable.

Further, from the test results of Samples 19 to 26, the structure of the ultra-thin film laminate was composed of an aluminum-rich Ti _x Al ₁ -xN compound in the range of 0 ≦ x <0.5,
<Y ≦ 1 titanium rich Ti _y Al _1-y N
It can be said that it is appropriate to alternately and repeatedly laminate the above compound to form an aluminum-rich Ti-Al-N compound as the whole thin film.

<Example 2> In order to confirm the wear resistance when the ultra-thin film laminate is applied to a wear-resistant film or a protective film of an electric / electronic component, the surface of a magnetic head is coated with the ultra-thin film laminate.
A contact wear test of the magnetic head with a magnetic disk was performed.

In this wear test, a sintered body (Vickers hardness 4000 kgf / mm ² ) made of aluminum and titanium carbide was used as a magnetic head, and this was pressed against a protective film on the surface of a magnetic disk with a load of 600 kgf / mm ^2. To
A CSS test was performed in which the magnetic disk was rotated at a high speed until the magnetic head floated, the rotation was stopped after the floating, and the magnetic head was brought into contact with the disk surface again. Here, the CSS test is a cycle test in which the magnetic head and the magnetic recording medium are set in contact with each other, the magnetic recording medium is rotated and levitated, the rotation is stopped, and the magnetic head and the magnetic recording medium are brought into contact again. It is.

Table 4 shows the results when 100,000 repetitive tests were performed by the CSS test method.

[0039]

[Table 4]

In Table 4, Samples 1 to 14 are examples using the ultra-thin film laminate according to the present invention, and were prepared by a sputtering method. Sample 15 is a comparative example in which SiO ₂ was used as a protective film.

The hardness of the coating layer was not measured because the layer was very thin and could not be measured.
Since there is an empirical positive correlation between the etching rate of the layer by KV) and the hardness, the etching rate is shown as an alternative value for the hardness.

From the results shown in Table 4, 0 ≦ x <0.5, 0.5
<Y ≦ 1 and the repetition lamination cycle is 0.5n
For Samples 2 to 5 in the range of m to 20 nm, no change was observed in the surface state and the reproduction output, and it was shown that the samples had excellent wear resistance as compared with other samples, particularly Sample 15 having a conventional structure. .

[0043]

As described above, the ultra-thin film laminate of the present invention can have both high hardness and oxidation resistance at the same time.
By using it for the coating layer of cutting tools and wear-resistant tools, it has superior wear resistance while maintaining the strength of the base material, and greatly extends the cutting life, especially in high-speed cutting and cutting of hard materials. Can be done.

In addition to the above-mentioned applications such as cutting tools, the ultra-thin laminate of the present invention provides a wear-resistant film and a protective film having excellent wear resistance on the surface of electric / electronic parts, sliding parts, and mechanical parts. It can be applied as a membrane.

Further, by using this ultra-thin film laminate, it is possible to provide a surface protective film such as a magneto-optical recording medium and an optical lens, or a thin film having excellent optical and electrical properties.

[Brief description of the drawings]

FIG. 1A is a schematic view showing a state in which a substrate is coated with an ultra-thin film laminate according to the present invention, and FIG. 1B is a partially enlarged view thereof.

FIG. 2 is a schematic view showing a state in which a substrate is coated with the ultra-thin film laminate according to the present invention via an interface layer.

FIG. 3 is a diagram showing a method for forming an ultra-thin film laminate according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ultra thin film laminated body 2 Substrate 3 Interface layer 4 Film forming apparatus 5, 6 Target 7 Substrate holder 8 Cutting tip

────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code FI C23C 16/34 C23C 16/34 28/04 28/04 (72) Inventor Tsuyoshi Yoshioka 1-1-1, Koyokita, Itami-shi Sumitomo (72) Inventor, Kazuo Yamagata 1-1-1, Kunyokita, Itami-shi, Itami Works, Sumitomo Electric Industries, Ltd. (56) References JP-A-3-120353 (JP, A) (58) 6) Surveyed field (Int.Cl. ⁶ , DB name) C23C 14/00-14/58 B23B 27/14 B23P 15/28 B32B 15/01 C22C 29/16 C23C 16/00-16/56 C23C 28/04 G11B 5/84 G11B 7/26

Claims (6)

(57) [Claims] 1. Ti _x Al _1-x N and Ti _y Al _1-y N constituted by Ti, Al and N (0 ≦ x <
An ultra-thin film laminate in which two kinds of compounds of 0.5 and 0.5 <y ≦ 1) are alternately and repeatedly laminated to make the overall composition of the laminate stoichiometrically aluminum-rich. 2. The ultra-thin film laminate according to claim 1, wherein a repetitive lamination period is 0.5 nm to 20 nm,
An ultrathin laminate having an overall film thickness of 0.5 μm to 10 μm. 3. The ultra-thin film laminate according to claim 1 or 2 is coated on a surface of a hard base material such as a WC-based cemented carbide, cermet, ceramics, high-speed steel, etc., and is used as a cutting tip, a drill or an end mill. The coating of the ultra-thin film laminate to be used. 4. The ultra-thin film laminate according to claim 1 or 2 is coated on the surface of a substrate, and a group IVa, Va, or VIa of the periodic table is provided between the ultra-thin film laminate and the substrate. An ultrathin film provided with an interface layer having a thickness of 0.05 μm to 5 μm and comprising at least one compound of a combination of at least one element selected from the group consisting of metal elements and at least one of C and N Laminate coating. 5. The ultra-thin film laminate according to claim 1, wherein the Vickers hardness used as an abrasion-resistant film or a protective film for electric / electronic parts, sliding parts, and mechanical parts is a load of 2.
An ultra-thin film laminate of 5 gf and 3500 kgf / mm ² or more. 6. The ultra-thin film laminate according to claim 5, wherein the total film thickness of the laminate is 5 nm to 10 μm.