JPH1018024A - Coated hard member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coated hard member excellent in adhesion with a substrate and excellent in wear resistance and chipping resistance. SOLUTION: On the surface of a substrate, via intermediate layer coating with 0.1 to 3.0μm thickness in which, in the case of being expressed by (Tia Mb Zrc ) Cx N1-x , M denotes at least one kind of element selected from the groups of Hf, V, Nb, Ta, Cr, Mo, W and Al, and their molar ratios satisfy 0.3<=a<=0.8, 0.2<=b<=0.7, 0.012<=c<=0.4 and 0<=X<=1, coating in which, in the case of being expressed by (Tia Mb )Cx N1-x , M denotes at least one kind of element selected from the groups of Hf, V, Nb, Ta, Cr, Mo, W and Al, and their molar ratios satisfy 0.3<=a<=0.8, 0.2<=b<=0.7 and 0<=X<=1 is formed by 0.1 to 10μm thickness as hard layer coating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutting tool having excellent wear resistance and chipping resistance, and a coated hard member used as a wear-resistant tool.

[0002]

2. Description of the Related Art Conventionally, in order to improve the wear resistance and chipping resistance of cutting tools or wear-resistant tools, physical vapor deposition (hereinafter, referred to as PV) has been proposed.
This is referred to as Method D. ) Or a chemical vapor deposition method (hereinafter referred to as a CVD method) on substrates such as tungsten carbide-based cemented carbide, titanium carbonitride-based cermet, and high-speed steel.
Periodic tables IVa, Va, VIa such as iN, Ti (C, N), CrN
Coating tools in which a hard layer coating of a group III carbide, nitride, or carbonitride is coated on a substrate are often used. In particular, since the film formed by the PVD method has a low film forming temperature of 500 ° C., there is almost no reaction between the film and the base material, and the base material strength can be utilized. Therefore, it is often used for milling throw-away tips, end mills and the like.

However, recently, it has become necessary to increase the cutting speed and to cut hard materials, so that the Ti-based carbides, nitrides, and carbonitrides have poor oxidation resistance, so that the cutting edge has a high temperature. Under such cutting conditions, the coating deteriorates drastically, and there is a problem that particles fall off the coating, heat cracks, chipping, etc. occur, and the cutting life is shortened. Therefore, it was initially developed for devices such as temperature sensors that take advantage of the temperature dependence of resistance (Ti, A
l) Attention has been paid to the N film. This coating has better oxidation resistance at high temperatures than the hard layer coating, and exhibits excellent performance even in high-speed cutting areas where the cutting edge is hot, and has a high Vickers hardness of 2300-3000 and excellent wear resistance. ing. For this reason, many studies have been made on cutting tools.

[0004] By forming an intermediate layer coating between the substrate and the hard layer coating or increasing or decreasing the addition amount of a specific element in the laminating direction, the addition amount is inclined to improve the familiarity with the substrate. Thus, it is known that the adhesion between the substrate and the hard layer coating can be increased and the internal stress can be reduced. For example, Japanese Patent Application Laid-Open No. Hei 6-32223 discloses a film characterized in that a mixed layer composed of both constituent elements is formed between a substrate and a film of a nitride compound composed of an element from Group IVa or IIIb of the periodic table and N. An adherend is described. Japanese Patent Application Laid-Open No. 6-17228 discloses a coating film in which a binary nitride selected from Ti and Al, Hf, and Zr is formed on the surface of a substrate and the amount of carbon is further increased toward the surface. A graded hard-coated cemented carbide characterized in that the surface forms the binary carbonitride is described.

[0005]

However, when the (Ti, Al) N film is formed on the substrate as the hard layer coating, the substrate is not well-adapted to the substrate even if the above-mentioned conventional various methods are used. And the internal stress is high. The present invention has solved the above-mentioned problems and has a method of forming a (Ti, Al) N
Film, furthermore, (Ti, Al) C film, (Ti, Al) CN
An object of the present invention is to provide a coated hard member having excellent wear resistance and chipping resistance by forming an intermediate layer coating having excellent adhesion to a film and excellent adhesion to a substrate.

[0006]

In order to achieve the above-mentioned object, the present inventor has proposed a substrate and a hard layer coating (Ti, Al).
As a result of studying various methods for improving the adhesion to the N film, it has been found that a ternary system containing Ti and Zr on
By forming an intermediate layer coating composed of elementary carbides, nitrides, and carbonitrides, it was found that the adhesion between the substrate and the intermediate layer coating and between the intermediate layer coating and the hard layer coating was increased, and the wear resistance was improved. Obtained. Further, the intermediate layer coating is composed of (Ti, A
1) It was found that the adhesiveness to the C, (Ti, Al) CN hard layer coating was excellent. That is, the present invention relates to PV
The D or CVD on the surface of the substrate (Ti _a M _b Z
r _c ) When represented by C _x N _{1 -x} , M is Hf, V, Nb, T
a, Cr, Mo, at least one element selected from the group consisting of W and Al, and the molar ratio of each is
0.3 ≦ a ≦ 0.8, 0.2 ≦ b ≦ 0.7, 0.01 ≦
Thickness of 0.1 to 3.0 μ, where c ≦ 0.4 and 0 ≦ X ≦ 1
m carbides, via an intermediate layer coating of a nitride or a carbonitride, when expressed in _{(Ti a M b) C x} N 1-x, M is H
f, V, Nb, Ta, Cr, Mo, W and at least one element selected from the group consisting of Al, and their molar ratios are 0.3 ≦ a ≦ 0.8, 0.2 ≦ b ≦ 0.
A coated hard member characterized in that a coating made of carbide, nitride or carbonitride of 7,0 ≦ X ≦ 1 is formed as a hard layer coating with a thickness of 0.1 to 10 μm. Further, the intermediate layer coating is a coated hard member in which the amount of Zr added is gradually reduced from the surface side of the substrate to the hard layer coating.

Since the hard coating of the present invention has an intermediate layer coating containing Zr in particular, it has good adhesion to substrates such as tungsten carbide-based cemented carbide, titanium carbonitride-based cermet, and high-speed steel. Excellent and low generation of internal stress. Further, since the surface portion does not contain Zr, a hard layer coating excellent in oxidation resistance can be formed. Furthermore, when the intermediate layer coating in which the Zr addition amount is gradually reduced from the substrate side toward the hard layer coating is provided, the adhesion between the intermediate layer coating and the hard layer coating is reduced because the Zr addition amount decreases gently. Are further excellent, and the generation of internal stress is further reduced.

[0008] The composition of the intermediate layer coating _{(Ti a M b Zr c)} C x
When represented by N _1-x , M is Hf, V, Nb, Ta, C
at least one element selected from the group consisting of r, Mo, W, and Al, each of which is a molar ratio,
0.3 ≦ a ≦ 0.8, 0.2 ≦ b ≦ 0.7, 0.01 ≦
The film is made of c ≦ 0.4 and 0 ≦ X ≦ 1. The reason for limiting the molar ratio of Ti is that if it is less than 0.3, sufficient adhesion as a base film cannot be obtained, and if it exceeds 0.8, the toughness decreases and the film becomes brittle. Hf, V, N
The reason for limiting the molar ratio of M, which is at least one element selected from the group consisting of b, Ta, Cr, Mo, W, and Al, is that if it is less than 0.2, the toughness decreases and the film becomes brittle. , 0.7, the oxidation resistance decreases. The range of the Zr addition amount was set to 0.01 to 0.4 because:
If it exceeds 0.4, the coating itself becomes brittle or the oxidation resistance is remarkably reduced, and if it is less than 0.01, the adhesion is reduced. In addition, the thickness of the intermediate layer coating is 0.1
The reason for limiting the thickness to 3.0 μm is that if the thickness is less than 0.1 μm, the film is too thin to obtain a desired adhesion, and if the thickness exceeds 3.0 μm, the coating itself becomes brittle.

[0009] Further, the hard layer film is made of (Ti _a M _b ) C _x N _1-x
Where M is Hf, V, Nb, Ta, Cr, M
o, at least one element selected from the group consisting of W and Al, and in each molar ratio, 0.3 ≦ a ≦
The film is made of 0.8, 0.2 ≦ b ≦ 0.7, and 0 ≦ X ≦ 1. The reason for limiting the molar ratio of Ti is that if it is less than 0.3, the hardness is low and abrasion easily proceeds, and if it exceeds 0.8, the oxidation resistance is reduced and the cutting life is shortened. Further, the reason for limiting the molar ratio of M, which is at least one element selected from the group consisting of Hf, V, Nb, Ta, Cr, Mo, W, and Al, is less than 0.2, the toughness is reduced, and the film becomes thin. This is because it becomes brittle, and if it exceeds 0.7, the oxidation resistance decreases. Further, the thickness of the surface layer is limited to 0.1 to 10 μm. If the thickness is less than 0.1 μm, the film is too thin to obtain desired oxidation resistance and abrasion resistance, and if it exceeds 10 μm, the adhesion decreases. Or the residual stress becomes too large and the film is easily peeled off.

It is also effective to obtain abrasion resistance by coating the coating of the present invention with different C / N mixing ratios to form a multilayer structure, or by continuously changing the C / N ratio to form a gradient composition coating. And is included in the technical scope of the present invention. Furthermore, the present invention does not limit the substrate on which the film is formed.
What is necessary is just to select suitably according to a use, such as a cemented carbide, a cermet, a high speed steel, or a wear-resistant alloy.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments. (Example 1) 84WC-3TiC-1TiN-3TaC
2.5 μm commercially available so as to have a composition of -9 vol% Co
WC powder 1.5 μm TiC powder, TiN powder,
A 1.2 μm TaC powder and a Co powder were mixed in a ball mill for 96 hours, dried, granulated, pressed into a throw-away chip shape, sintered, and processed into a predetermined tool shape to obtain a cemented carbide tool. Various Ti, Hf, V,
A binary or ternary alloy target with a metal selected from the group consisting of Nb, Ta, Cr, Mo, W and Al;
And an alloy target of Zr were prepared, and various coatings shown in Table 1 were prepared by an arc ion plating method.
First, a ternary or quaternary intermediate layer film containing Ti and Zr was formed to a thickness of 0.5 μm. Next, the current value of the binary target was kept constant, and the current value of the Zr target was gradually lowered to produce an intermediate layer film 2.0 μm in which the Zr addition amount was gradually decreased toward the hard layer film. Finally Z
The current value of the r target was set to zero to form a binary or ternary hard layer coating of 0.5 μm. Table 1 shows the evaluation results of the critical load value of each test piece by a scratch tester. Further, Table 2 shows the results of evaluation by a similar scratch tester in the conventional case where no intermediate layer film containing Zr was formed.

[0012]

[Table 1]

[0013]

[Table 2]

From Tables 1 and 2, all of the coatings are formed as ternary or quaternary films in which Zr is added to the intermediate layer coating, so that the conventional binary or ternary single films are formed. It can be seen that the critical load value is larger than that of the layer film and the adhesion is improved.

(Example 2) 84WC-3TiC-1Ti
A commercially available 2.5 μm WC powder 1.5 μm TiC powder having a composition of N-3TaC-9 vol% Co
The iN powder, the 1.2 μm TaC powder, and the Co powder were mixed in a ball mill for 96 hours, dried, granulated, pressed into a throw-away chip shape, sintered, and worked into a predetermined tool shape. Various alloy targets were prepared on the cemented carbide tool by the arc ion plating method, and a coating as shown in Tables 3 and 4 was formed to 3.0 μm. In the same manner as described above, the composition of the coating was 0.5 μm for the intermediate coating, and 2.0 for the intermediate coating in which the amount of Zr was gradually decreased toward the hard coating.
μm, hard layer coating: 0.5 μm.

[0016]

[Table 3]

[0017]

[Table 4]

Then, these coated carbide tools were milled under the following cutting conditions, and the maximum wear amount was 0.2 mm.
Tables 3 and 4 together show the results obtained for the cutting lengths up to
Shown in Work material SKD61 (HB: 190-220) Cutting speed 250m / min Feed 0.2mm / tooth Cutting depth 2.0mm Cutting oil None In addition, as a conventional material, each binary single-layer coating has the same shape by arc ion plating. Fabricated on a carbide tool
Table 5 shows the results of the evaluation. Further, Table 6 shows a comparative example in which the Zr addition amount of the intermediate layer coating was out of the range of the present invention.

[0019]

[Table 5]

[0020]

[Table 6]

As can be seen from Tables 3, 4 and 5, by forming a ternary or quaternary film in which Zr is added to the intermediate layer coating, the cutting length until the maximum wear amount reaches 0.2 mm is also obtained. It can be seen that it is longer than the conventional material and the wear resistance is improved. Also, as shown in Table 6, when the Zr addition amount of the intermediate layer coating exceeds 0.4 as in the comparative example, the cutting length is shortened and the wear resistance is reduced. It turns out to be good.

[0022]

The coated hard alloy of the present invention has a T
i, Zr and nitride, carbide and carbonitride containing at least one element selected from the group consisting of Hf, V, Nb, Ta, Cr, Mo, W and Al as an intermediate layer coating, and a hard layer coating Forming a nitride, carbide, and carbonitride film made of at least one element selected from the group consisting of Ti and Hf, V, Nb, Ta, Cr, Mo, W, and Al The adhesiveness is improved, the oxidation resistance and abrasion resistance are excellent, and a remarkably long life can be obtained.

Claims (2)

[Claims] To 1. A substrate surface _{(Ti a M b Zr c)} C x N
_When represented by _1-x , M is Hf, V, Nb, Ta, Cr,
At least one selected from the group consisting of Mo, W and Al
Species, and the molar ratio of each is 0.3 ≦ a ≦
0.8, 0.2 ≦ b ≦ 0.7, 0.01 ≦ c ≦ 0.4,
0 through the intermediate layer coating of a thickness of 0.1~3.0μm consisting _{≦ X ≦ 1, (Ti a} M b) C x when expressed in N _1-x, M is Hf, V, Nb, Ta , Cr, Mo, W and Al are at least one element selected from the group consisting of 0.3 ≦ a ≦ 0.8, 0.2 ≦ b ≦
A coated hard member characterized in that a coating consisting of 0.7,0 ≦ X ≦ 1 is formed as a hard layer coating with a thickness of 0.1 to 10 μm. 2. The coated hard member according to claim 1, wherein the Zr addition amount of the intermediate layer coating is gradually reduced from the surface side of the substrate toward the hard layer coating.