JPS62290861A - Titanium compound coated material having superior film adhesion and wear resistance - Google Patents

Abstract

PURPOSE:To obtain a Ti compound coated material having superior wear resistance and film adhesion by forming an inner layer of metallic Ti having a prescribed thickness and an outer layer of a specified Ti compound on the surface of substrate. CONSTITUTION:Ti is evaporated and a metallic Ti layer having >=0.05mum thickness is formed as an inner layer on the surface of a substrate of high-speed steel or the like by a reactive ion plating method utilizing hollow cathode discharge. A coating layer of one or more kinds of Ti compounds selected among TiN, TiC and Ti (C, N) is then formed as an outer layer with gaseous N2, gaseous C2H2 or a gaseous C2H2-N2 mixture as a reactive gas. Thus, the adhesion of the resulting film can be improve without lowering the hardness or deteriorating the wear resistance. The Ti compound coated material is especially suitable for a cutting tool or a metallic mold.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention (Field of Industrial Application) This invention relates to a titanium compound coating material that has poor film adhesion and wear resistance, and is particularly applicable to indexable chips and molds. The abrasion resistance of the tool is improved by coating the tool with a titanium compound with good adhesion.

(Prior art) Conventionally, in order to impart properties such as corrosion resistance and wear resistance to metal materials, ceramic films such as titanium nitride and titanium carbide have been coated using physical vapor deposition or chemical vapor deposition. There is.

However, the films obtained by conventional methods have insufficient adhesion to the substrate, especially when the film thickness is 5 μm or more.
Thermal stress caused by the difference in thermal expansion coefficient with the base material and residual stress caused by crystal distortion within the thin film act as a dog, causing the film to become (
There was a drawback that separation was likely to occur.

To solve this problem, a method of controlling the voltage applied to the base material according to the thickness of the deposited film (Japanese Patent Laid-Open No. 60-967
54) and a method of similarly controlling the substrate temperature according to the film thickness (Japanese Unexamined Patent Publication No. 104661/1983).

The above-mentioned method improves adhesion and makes it possible to coat a thick film of approximately 30 μm. However, in both methods, when compared with the conventional method, the crystal structure near the surface of the film becomes less dense, resulting in a decrease in hardness. There was a problem in terms of wear resistance.

The pond base material is plated with a high melting point metal in advance and then PVD is applied.
A method for doing this has also been published (Japanese Patent Application Laid-Open No. 59-17812
Publication No. 2). However, this method adds a new process called wet plating as a means of forming the intermediate layer.
Not only was it extremely disadvantageous in terms of economics and the environment such as waste liquid treatment (IF production), but it also left a problem in that it was not as effective in improving adhesion as the number of new processes increased. .

(Problems to be Solved by the Invention) As mentioned above, to date, there has been no ceramic-coated tool that is fully satisfactory in both film adhesion and wear resistance, and there has been a demand for the development of such a tool. .

This invention was developed in view of the above-mentioned current situation.
The object of the present invention is to propose a new ceramic coating material with improved coating adhesion without the disadvantage of decreasing coating hardness and thus deteriorating wear resistance.

(Means for Solving the Problems) That is, the present invention provides an inner layer with a thickness of:
A metal titanium layer of 0.05 μm or more, and a TiN, TiC or Ti layer formed over the metal titanium layer as an outer layer.
It is a titanium compound coating phase that is characterized by having a coating layer of a titanium compound made of at least one of (C,N), and has excellent coating adhesion and wear resistance.

In this invention, the thickness of the inner metallic titanium layer is 0.
If the thickness is less than 0.05 μm, good coating adhesion as expected in this invention cannot be obtained, so the metallic titanium coating thickness should be 0.0 μm.
The amount is limited to a range of 5 μm or more, preferably 0.2 μm or more. Note that the upper limit is preferably about 2 μm.

In addition, the thickness of the titanium compound coating that is the outer layer is 1.0~
Approximately 20 μm is suitable.

The adhesion of a thin film is thought to depend on the crystal consistency between the thin film and the base material, the internal stress within the thin film, and the voltage applied to the base material during coating.
1), this T1 coating has good crystal consistency with the titanium compounds of the base material and the outer layer, and the titanium atoms diffuse to each, and moreover, it generates intermetallic compounds that deteriorate adhesion. Nor. It was also discovered that the material also has grooves that relieve internal stress within the titanium compound of the outer layer.

In addition, generally, the higher the voltage applied to the base material, the better the adhesion of the thin film to the base material and the higher the hardness.

However, at the same time, crystal lattice strain within the thin film increases, internal stress increases, and peeling becomes easier. Therefore, for the voltage applied to the base material, there is an appropriate voltage depending on the respective film thickness and film quality.

Below, the experimental results that led to this invention will be explained. In the experiment, a reactive ion brating method using hollow cathode discharge was adopted as a representative example of the ion blating method, and 5US304 steel was used as the base material, and the inner layer was coated with Ti and the outer layer was coated with titanium nitride (TiN). It was done by

First, argon gas was introduced to generate a hollow cathode discharge, and a low voltage and large current electron beam was introduced from the hollow cathode into the evaporation source to evaporate T1.

At that time, an inert gas or reactive nitrogen gas was introduced to ionize the gas or vapor to deposit T1 or T + N on the substrate.

In Figure 1, the inner layer T is
The results of investigating the relationship between the film thickness of the inner layer T1 and film adhesion when coating TiN with a thickness of 10 μm by introducing reactive nitrogen gas and applying a voltage of -20 V are shown. . Note that the inner layer Ti coating thickness and outer layer Ti
N coating thickness was measured during the coating process by a pre-calibrated coating thickness monitor. Adhesion was evaluated by immersing the film in liquid nitrogen for 5 minutes and determining the number of peels per unit area of the surface at that time.

As is clear from the figure, the inner layer T1 coating thickness is 0.05μ
Good adhesion was obtained when the thickness was m or more.

Figure 2 shows the relationship between the applied voltage and adhesion in the inner layer T1 when the inner layer T1 is coated with a thickness of 0.5 μm and then TiN is coated with an applied voltage of minus 20 μm to a thickness of 10 μm. The results of the investigation are shown below.

As is clear from the figure, good film adhesion was obtained when the applied voltage was in the range of -20 V to -1000 V.

Next, Figure 3 shows how the outer layer TiN was coated with the inner layer Ti to a thickness of 0.5 μm at an applied voltage of -100μ, followed by the outer layer TiN coated with a thickness of 10 μm at various applied voltages.
The results of an investigation into the relationship between the applied voltage during coating, adhesion, and film hardness are shown.

The film hardness was measured using a Knoop indenter (load: 25 g).

As is clear from the figure, as the absolute value of the applied voltage increases, the adhesion deteriorates. On the other hand, the coating hardness increases as the absolute value of the applied voltage increases.

The reason for this is thought to be that as the applied voltage increases, the compressive internal stress within the film increases. Therefore, it is preferable that the applied voltage be between -5 cm and -500 cm, more preferably between -IOV and -30 V.

From the above experiments, when coating the substrate surface with Ti and then TiN according to the present invention, firstly, when coating the inner layer Ti coating, the film thickness is 0.05 μm or more, preferably 0.2 μm or more.
μm or more, the applied voltage is between -20V and -1000cm, preferably between -90V and -1130cm, while the outer layer Ti
When coating with N, the applied voltage ranges from -5V to -500V.
It has proven particularly advantageous to operate preferably in the range -10V to -30V.

In the above experiment, we mainly explained the case where TiN coating is applied by introducing only reactive N2 gas after coating with T1 film, but as the reactive gas, C2H2 gas or C2H gas
It is also possible to use a mixed gas of 2 and N2, and thus the outer coating can be made of TiN, titanium carbide (TiC),
Titanium carbonitride [Ti (C, N> E) can also be used. In this case, the preferred film thickness of the inner layer T11 and
The preferred range of the applied voltage during vapor deposition of the outer layer titanium compound is almost the same as in the case of TiN described above.

Furthermore, in the above experiment, we mainly explained the case where the reactive ion blating method (H9C, D, method) using hollow cathode discharge was used as the ion blating method, but the inner layer T1 coating and the outer layer titanium compound coating were The coating method is not limited to the H, C, and D methods, and for example, a high frequency excited ion blating method, a flute arc method, etc. can also be used.

By the way, when using the high frequency ion blating method, the preferred range of applied voltage when coating the inner layer T1 is -500 to -1000V, and the preferred range of applied voltage when coating the outer layer is -200 to -500 (at 7 degrees). be.

(Function) Although it is possible to improve adhesion without deteriorating wear resistance by forming a T1 film prior to coating with a titanium compound according to the present invention, it is presumed that this is due to the following reasons. Ru.

The reason is that the T1 base coating ++q has a mechanism that adheres well to the outer layer titanium compound (tlv 3000 or more) having normal hardness and the base material, and also relieves internal stress within the outer mold coating. It is assumed that this is due to the following.

(Example) Example 1 The surface of an indexable tip made of high speed steel 5KII-ll was coated with TI and then TiN by an activated reaction ion blating method using hollow cathode discharge. The coating conditions are as shown in Table 1.

Diameter using each indexable tip obtained? On
+m 545C normalized material (Hvl, 67) as the material to be cut, depth of cut: 1.5 mm, feed: 0.15 m1
A cutting test was conducted under conditions of Tl/rev and cutting speed: 30 m/min.

The results of investigating the side flank wear width and crater wear depth when such a continuous cutting test was conducted are shown in FIGS. 4 and 5.

As is clear from Figure 4.5, all the titanium compound coating materials (symbols Δ to D) according to the present invention exhibit greater wear resistance than the comparative examples, and have the same amount of wear when compared to the untreated material. The lifespan was 2 to 3 times longer.

Further, as shown in Table 1, all wear conditions were normal and no peeling was observed as seen in the comparative example.

Example 2 A P40 grade cutting indexable tip was coated with Ti and then Ti(C,N) (TicO, sNo,
4) The coating was applied to the blade diameter.

Using each coated indexable tip obtained in this way, the workpiece to be cut is: JIS-Fe12 (hardness H3
:180), Cutting speed: 200m/min, Depth of cut: 2mm, Feed: 45mm/rev, Chip shape:
A cutting test was conducted under the conditions of SNMN432, and the life time was measured. The results are also shown in Table 2.

The coated chips (symbols A-D) according to the invention all have
It exhibited a longer service life than Comparative Material X-Z, and no peeling was observed, indicating normal wear in all cases.

(Effects of the Invention) Thus, according to the present invention, it is possible to fG a titanium compound coating material that has both wear resistance and film adhesion, and is particularly effective when applied to cutting tools, molds, etc. .

[Brief explanation of drawings]

Figure 1 is a graph showing the relationship between the inner layer Ti film thickness and adhesion. Figure 2 is a graph showing the relationship between the applied voltage and adhesion when coating the inner layer Ti film. Figure 3 is the outer layer Ti film thickness. A graph showing the relationship between applied voltage, adhesion, and film hardness during TAN coating. Figure 4 is a graph showing the relationship between cutting time and flank wear. Figure 5 is a graph showing the relationship between cutting time and crater wear. This is a graph showing the relationship between Patent Applicant Kawasaki Steel Corporation 1<Return Number (pcs/crn') If<lk
Atsushi (appetizer 1/ and m') - Ikari 6 kuchei ≧

Claims (1)

[Claims] 1. A titanium compound consisting of a metallic titanium layer with a thickness of 0.05 μm or more as an inner layer and at least one of TiN, TiC or Ti (C, N) formed on the surface of the substrate, overlapping the metallic titanium layer as an outer layer. A titanium compound coating material with excellent film adhesion and wear resistance, characterized by comprising a coating layer.