JPH10309605A - Coated hard alloy tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coated hard alloy tool having a coating layer which is as hard as possible and excellent in wear resistance. SOLUTION: In such multilayer coat that at least two kinds of compound selected from a group which consists of nitride, carbide, carbon nitride and oxide of a periodic table IVa, Va group element, Al, B, Ga and these mutual alloy or solid solution, are laminated in alternating on a base metal by 0.2 to 100 nm of coating thickness and 0.5 to 10 μm of coating thickness in total, at least one kind selected from a group consisting of Ge, Sn and Pb is added to at least one kind of compound layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a coated hard alloy having excellent wear resistance, particularly excellent welding resistance, among coated hard alloy tools used as cutting tools or other wear-resistant tools requiring wear resistance. For tools.

[0002]

2. Description of the Related Art Conventionally, as a cutting tool, a cemented carbide (an alloy obtained by adding a carbon nitride of Ti, Ta, or Nb to a WC-Co alloy) has been used. Accordingly, carbides, nitrides, carbonitrides such as metals such as IVa, Va, VIa group metals and Al of the periodic table of elements are formed on the surface of a cemented carbide, cermet or alumina-based or silicon nitride-based ceramic by PVD method. The use ratio of hard alloy tools coated with a film made of a material, boronitride or oxide to a thickness of 3 to 20 μm is increasing. In particular, in the case of coating by the PVD method, since the wear resistance can be increased without deteriorating the strength of the base material, such a surface coating method is used for cutting tools requiring high strength such as drills, end mills, indexable inserts for milling. It is heavily used.

For example, wear resistance of the cutting tool, in order to improve the chipping resistance, the surface of the hard alloy of cemented carbide or cermet PVD or CVD (Ti _a Al _b Si
_c ) C _x N _1-x [0.3 ≦ a ≦ 0.8, 0.2 ≦ b ≦
A coated hard alloy coated with a hard coating of 0.5 to 10 μm represented by [0.7, 0 ≦ x ≦ 1, 0.01 ≦ c ≦ 0.2] has been proposed. However, in this case, improvement in wear resistance was not sufficient. Furthermore, in order to improve the wear resistance, the thickness of one layer is reduced to 0.2 to 100 nm,
It has been found that when hard materials are alternately formed, the internal strain increases due to mutual interaction, and a high hard film is formed. This method has been put to practical use (Japanese Patent Laid-Open No. 8-12).
No. 7862). In other words, this method is characterized by disposing a specific intermediate layer between the laminated portion and the substrate for the purpose of stabilizing the strain matching between the multilayer film and the substrate. Not enough.

[0004]

According to the above-mentioned method for stabilizing the strain matching, the intermediate layer and at least the layer closest to the base material of the laminated portion have a continuous crystal lattice, and the two layers interact with each other. Although large strain is generated and high hardness is obtained, in terms of stabilizing the strain matching, the interaction with the dissimilar elements is weaker at the part away from the interface between the base material and the multilayer film, and the strain structure is stable. There was a problem that it was difficult to convert. The present invention has been made in order to solve the above-mentioned various problems of the conventional method, and in particular, has further developed a method for stabilizing the strain matching, and has a coating having a harder and more wear-resistant coating layer. It is an object to provide a hard alloy tool.

[0005]

The object of the present invention can be attained by the inventions having the following constitutions. (1) At least two elements selected from the group consisting of nitrides, carbides, carbonitrides, and oxides of the periodic table IVa, Va group elements, Al, B, Ga and their alloys or solid solutions.
At least one compound layer is made of Ge or Sn in at least one compound layer of a multilayer film having a total thickness of 0.5 to 0 μm by alternately laminating seed compounds in a thickness of 0.2 to 100 nm on a base material. And P
A coated hard alloy tool, wherein at least one member selected from the group consisting of b is added. (2) The coated hard alloy tool as described in (1) above, wherein the addition amount of at least one selected from the group consisting of Ge, Sn, and Pb is set to an atomic ratio of at most 20%. (3) The coated alloy hard tool according to the above (2), wherein the amount of addition of at least one selected from the group consisting of Ge, Sn and Pb is 0.01 to 5% in atomic ratio.

(4) A thin film made of a nitride, carbide, carbonitride or oxide of a group IVa element is disposed at the interface between the base material and the multilayer coating film. The coated hard alloy tool according to any one of the above. (5) The method according to any of (1) to (3) above, wherein a thin film made of a nitride, carbide, carbonitride or oxide of a Group IVa element is disposed on the outermost surface of the multilayer coating film. Coated hard alloy tool. (6) A thin film made of a nitride, carbide or carbonitride or oxide of a group IVa element is disposed on the interface between the base material and the multilayer coating film and on the uppermost surface of the multilayer coating film. Coated hard alloy tools. (7) The coated hard alloy tool according to any one of the above (1) to (6), wherein the base material is a cemented carbide, cermet, alumina-based or silicon nitride-based ceramic.

The present inventors have considered the stress-strain of a multilayer film having a continuous crystal lattice structure as follows. In a multilayer film having a continuous crystal lattice, a large strain is generated due to mutual interaction and a high hardness is obtained. On the other hand, if the stabilization of the strain matching is not sufficient, a brittle phenomenon of the film due to a high internal stress also appears. Here, the stabilization of the strain matching becomes more important as the distance from the interface of the multilayer film increases. This is because the interaction with the dissimilar element is weak in a portion away from the interface, so that it is difficult to stabilize the strained structure. Here, the method of stabilizing the strained structure was examined repeatedly, and it was found that hard materials for forming a multilayer film such as group IVa elements, group Va elements, nitrides of Al, B, and Ga, carbides, carbonitrides, and oxides were used. It has been concluded that the addition of elements such as Ge, Sn and Pb can stabilize the strain matching, and a coated hard alloy tool having high hardness and good wear resistance could be obtained.

The effect of the additive element concentration (atomic ratio) is effective from 0.005%, and the effect is remarkable especially in the range of 0.01 to 5%. However, when the concentration exceeds 20%, improvement in wear resistance cannot be expected. Was. In addition, at the interface with the base material and the outermost layer, IVa
It has also been discovered that if a thin film made of a nitride, carbide, carbonitride, or oxide of a group III element is provided, even if a crack is formed in the multilayer film, the effect of inhibiting the progress of the crack and the abrasion resistance are improved. did.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the above invention (1), the thickness of each hard layer is limited to 0.2 to 100 nm.
If the thickness is less than 100 nm, it is difficult to obtain a laminated structure, and the intended effect of the present invention cannot be obtained. If the thickness exceeds 100 nm, high hardness due to the laminated structure does not appear. The reason why the total thickness of the laminate is limited to 0.5 to 10 μm is that if it is less than 0.5 μm, the effect of wear resistance cannot be obtained, and if it exceeds 10 μm, the fracture resistance decreases.

In the above inventions (2) and (3), the concentration of the additive element is limited to a maximum of 20% in atomic ratio,
This is because no further improvement in wear resistance can be obtained even when the atomic ratio exceeds 0.01%.
If the content is less than 0.01%, the effect is considerably reduced, and the brittleness of the film is not improved. If the content is more than 5%, a problem occurs that the wear resistance is gradually reduced. In the above invention (4), disposing the specific thin film at the interface between the base material and the multilayer coating film prevents cracks,
This is because the effect of further improving abrasion resistance is obtained. In the above invention (5), disposing the specific thin film on the outermost surface of the multilayer coating film is not chemically very stable. This is because the effect of preventing the added element from touching the atmosphere can be obtained. The thickness of the thin film is 0.
The thickness is preferably in the range of 1 to 5 μm. If the thickness is less than 0.1 μm, the above effect is not obtained. Further, the cemented carbide, cermet, alumina-based or silicon nitride-based ceramic used as the base material in the present invention can be any material used as the base material of this type of coated hard alloy tool, and almost the same. The effect can be achieved.

[0011]

Embodiments of the present invention will be described below in detail. (Example 1) ISO P having shape of model number SDKN42MT
As shown in Table 1, TiGeN
(Ti: 95%, Ge: 5% in atomic ratio) and AlGeN
(Atomic ratio: Al: 95%, Ge: 5%) with a lamination interval of 0.1.
A laminated tool of 5 nm (sample A1) and 10 nm (sample B1) was manufactured.

HfPbC (Hf: 99% in atomic ratio,
Pb: 1%) and NbGeO (Nb: 80% by atomic ratio, G
e: 20%) with a lamination interval of 1 nm (sample C1) and 10 nm.
nm (sample D1) and ZrSnCN
(Zr: 99.9%, Sn: 0.1% in atomic ratio) and VS
nPbN (V: 90%, Sn: 5%, Pb: 5 in atomic ratio)
%) With a stacking interval of 0.2 nm (sample E1) and 100 n
m (sample F1). TiPbN (Ti: 90%, Pb: 10% in atomic ratio) and TiAlN (Ti: 50%, Al: 50% in atomic ratio) have a stacking interval of 0.5%.
A tool laminated with a thickness of 10 nm (sample G1) and a thickness of 10 nm (sample H1) was manufactured. The total film thickness of all the samples was set to 3 μm.

On the other hand, a sample obtained by the conventional technique, TiN and AlN were stacked at a stacking interval of 0.5 nm (sample ratio 1), 10 nm (sample ratio 2), HfC and NbO were stacked at a stacking interval of 1 nm (sample ratio 3), 10 nm (sample ratio 4), stacking interval of ZrCN and VN 0.2 nm (sample ratio 5), 100 nm (sample ratio 6), TiN and Ti
AlN is deposited at a stacking interval of 0.5 nm (sample ratio: 7), 10 n
m (sample ratio 8) was also prepared for comparison.

Using these samples, a block of alloy steel was cut under the following conditions, and the wear of each tool was measured. Cutting conditions Work material: SCM435 (Hardness: HB250) Cutting speed: 200m / min Feed: 0.25mm / tooth Cutting depth: 1.5mm Cutting form: Dry cutting length: 2m Cutting method: Milling

[0015]

[Table 1]

From these results, it can be seen that the sample on the left side of the above table, which is a product of the present invention, has higher wear resistance than the sample to which Ge, Sn, and Pb elements are not added.

(Example 2) Next, in order to confirm the effect of disposing a thin film made of a nitride, carbide, carbonitride or oxide of a Group IVa element at the interface between the base material and the multilayer coating film, the effect of Example 1 was confirmed. As shown in Table 2, TiN, ZrC, HfO, Ti
Samples on which CN and TiZrN layers were formed were prepared, cut under the same conditions as in Example 1, and the wear resistance was evaluated. Also in this example, the total coating film thickness was unified to 3 μm.

[0018]

[Table 2]

From these results, the sample on the left side of Table 2 above in which a thin film made of a nitride, carbide, carbonitride, or oxide of a group IVa element was provided at the interface between the base material and the multilayer coating film as a crack prevention layer was obtained. It can be seen that the sample having no crack prevention layer (the right side of the table) has superior wear resistance.

Example 3 Next, the same as the sample of Example 1 to confirm the effect of disposing a thin film made of a nitride, carbide, carbonitride or oxide of a group IVa element on the multilayer coating film. As shown in Table 3, a sample having a TiN, ZrC, HfO, and TiCN layer formed on the outermost surface of the coating film was prepared, and cut under the same conditions as in Example 1 to evaluate abrasion resistance. Also in this experiment, the total coating film thickness was unified to 3 μm.

[0021]

[Table 3]

From the results, the sample on the left side of Table 3 above in which a thin film made of a nitride, carbide, carbonitride, or oxide of a Group IVa element was disposed on the multilayer coating film had no surface layer. It can be seen that the abrasion resistance is better than (right).

Example 4 Next, the effect of disposing a thin film made of a nitride, carbide, carbonitride or oxide of a group IVa element on the interface between the base material and the multilayer coating film and on the multilayer coating film As shown in Table 4, TiN, ZrC, HfO, and Ti were formed between the interface between the coating film and the base material and the outermost surface of the coating film as in the sample of Example 1 to confirm that
A sample on which a CN layer was formed was prepared, cut under the same conditions as in Example 1, and the wear resistance was evaluated. Also in this example, the total coating film thickness was unified to 3 μm.

[0024]

[Table 4]

From the results, the sample on the left side of Table 4 above is composed of a nitride, carbide, carbonitride or oxide of an IVa group element on the outermost surface layer of the multilayer coating film and the interface between the base material and the multilayer coating film. It can be seen that the abrasion resistance is superior to the sample without the thin film (right side).

(Example 5) Next, in order to confirm the effect of the concentration of the added element on the wear resistance, an ISOP39 cemented carbide base material having the shape of model number SDKN42MT was added to TiGeN (Ti in atomic ratio) as shown in Table 5. : 99.9%, Ge:
0.1%) and AlGeN (Al: 95% by atomic ratio, G
e: 5%) with a lamination interval of 0.5 nm (sample α), TiGeN (Ti: 95% by atomic ratio, Ge:
5%) and AlGeN (atomic ratio: Al: 95%, Ge: 5
%) At a lamination interval of 0.5 nm (sample β), and TiGeN (Ti: 80% by atomic ratio, G
e: 20%) and AlGeN (Al: 95% by atomic ratio, G
e: 5%) with a stacking interval of 0.5 nm (sample γ), and TiGeN (Ti: 75% by atomic ratio,
Ge: 25%) and AlGeN (Al: 95% by atomic ratio,
Ge (5%) was laminated at a lamination interval of 0.5 nm to prepare a tool (sample δ), which was cut under the same conditions as in Example 1 to evaluate wear resistance. Also in this example, the total coating film thickness was unified to 3 μm. Table 5 also shows data of sample ratio 1.

[0027]

[Table 5]

From these results, it was found that the amount of the added element was 20 in atomic ratio.
%, The effect is recognized, and it is apparent that the effect is particularly remarkable at 5% or less. At 0.01%, a remarkable effect is observed.

[0029]

As described above, the coated hard alloy tool of the present invention has an effect that the wear resistance is greatly improved as compared with the conventional multilayer coated sintered alloy, and the tool life is thereby improved. There is a remarkable effect of improving.

Claims (7)

[Claims] 1. The periodic table IVa, a Va group element, Al,
Nitrides of B, Ga and their alloys or solid solutions,
At least two types of compounds selected from the group consisting of carbides, carbonitrides and oxides are alternately stacked on the base material in a thickness of 0.2 to 100 nm to form a total thickness of 0.5 to 10 μm.
Of at least one compound layer in the multilayer film
at least one selected from the group consisting of e, Sn and Pb
A coated hard alloy tool characterized by adding a seed. 2. The coated hard alloy tool according to claim 1, wherein the addition amount of at least one element selected from the group consisting of Ge, Sn and Pb is set to an atomic ratio of at most 20%. 3. The amount of at least one selected from the group consisting of Ge, Sn and Pb is 0.01 to 5% by atomic ratio.
The coated alloy hard tool according to claim 2, wherein: 4. An IV is formed at the interface between the base material and the multilayer coating film.
The coated hard alloy tool according to any one of claims 1 to 3, wherein a thin film made of a nitride, carbide, carbonitride or oxide of a group a element is provided. 5. The multilayer coating film according to claim 1, wherein a thin film made of a nitride, carbide, carbonitride or oxide of a group IVa element is disposed on the outermost surface. Coated hard alloy tools. 6. A nitride of a group IVa element on the interface between the base material and the multilayer coating film and on the uppermost surface of the multilayer coating film.
The coated hard alloy tool according to claim 1, wherein a thin film made of a carbide carbonitride or an oxide is provided. 7. The coated hard alloy tool according to claim 1, wherein the base material is a cemented carbide, cermet, alumina-based or silicon nitride-based ceramic.