KR100889372B1 - Multi-layer hard film having good thermal stability - Google Patents

Abstract

The present invention relates to a rigid multilayer thin film having excellent thermal stability, and more particularly, to a multilayer structure in which at least one thin film unit composed of a TiAlN film layer and a BN film layer is laminated, and a thin film with a thickness control of each TiAlN film layer and a BN film layer. By controlling the thickness of the unit, it improves thermal stability at high temperature and improves abrasion resistance by high hardness even at high temperature from room temperature to 900 ° C. Therefore, it is used as a material for surface coating of cutting tools and fine precision parts. The present invention relates to a hard multilayer thin film in which an effect of improving is expected.

Hard multilayer thin films, TiAlN, BN, metal nitrides, hardness, thermal stability

Description

Multi-layer hard film having good thermal stability

1 is a schematic diagram of a physical vapor deposition sputtering apparatus as one apparatus for depositing a multilayer thin film.

FIG. 2 illustrates a cross-sectional TEM image of a thin film of TiAlN / BN multilayer thin film deposited on M2 HSS (high speed steel) using the apparatus of FIG.

3 shows a cross-sectional high resolution TEM (HRTEM) image of a thin film of TiAlN / BN multilayer thin film deposited on M2 HSS (high speed steel) using the apparatus of FIG.

<Description of the symbols in the drawing>

1: Chamber 2: Target sputtering gun (GUN)

3: jig system 4: specimen for deposition

5: target plasma

The present invention relates to a rigid multilayer thin film having excellent thermal stability, and more particularly, a Ti _1-x Al _x N film layer (0 ≦ _x ≦ 1, hereinafter referred to as a “TiAlN film layer”) and a boron nitride film layer (hereinafter, “ BN film layer ”) is formed of a multi-layer structure in which at least one thin film unit is laminated, and the thermal stability at high temperature by controlling the thickness of each TiAlN film layer and the BN film layer and the thickness of the thin film unit to achieve thermal stability at room temperature to 900 The present invention relates to a hard multilayer thin film, which is expected to have an effect of improving the surface strength when used as a material for surface coating of cutting tools and micro precision parts, even at high temperature conditions.

As the manufacturing process is automated and speeded up due to the development of the mechanical industry, high-strength mechanical structures such as automobiles and shipbuilding, various mechanical parts, molds, cutting tools, etc., reach high temperatures in use, In addition to physical properties, thermal stability that can be used stably at high temperatures is required. In addition, these components are required for physical properties such as hardness and wear resistance in addition to thermal stability. Since these components mainly use the surface layer, the physical properties of the surface layer determine the performance and life of the component. In order to improve the performance and life of these various mechanical parts, the surface of the part is coated (coated) with a film having excellent mechanical properties such as hardness and wear resistance. Eventually the performance of the coating will determine the performance of the machine structure, molds and cutting tools.

As a material for surface coating, materials such as carbide, nitride, carbonitride or aluminum oxide based on group IV-A elements such as titanium (Ti) are generally used. These coating materials mainly form a film on the surface of a part by using physical vapor deposition (PVD) or chemical vapor deposition (CVD). Recently, TiAlN coating layer added aluminum (Al) to nitrides of group IV-A elements such as titanium (Ti) has replaced the existing coating materials due to its excellent hardness and oxidation resistance. have.

However, in order to improve the productivity and lifetime of products by processing and processing these materials in conjunction with the development of stronger materials, efforts to further improve hardness and oxidation resistance by adding various elements such as boron (B) to TiAlN Has been. [Thin Solid Film 343-344 (1999) 242-245, Surface and Coatings Technology 158-159 (2002) 664-668]

On the other hand, such various mechanical parts are most often used at a high temperature. Therefore, even when used at a high temperature, a technique for preventing the hardness of the coating film from decreasing is required.

Veprek et al. Proposed a TiAlN / a-BN nanocomposite as a material having excellent hardness and high temperature stability. [Thin Solid Film, 476 (2005) 1-29, Elsevier] TiAlN / a-BN nanocomposites were prepared by co-deposition, but TiAlN particle size and amorphous surrounding these particles It has been reported that the thickness of the BN film is not easily controlled independently, and that the physical properties such as hardness are lowered due to the infiltration of impurities such as oxygen when not deposited under high vacuum (<10 ⁻⁷ torr).

In addition, Yamamoto et al. Repeats a hard coating layer (layer B) having a non-rock salt structure on a hard coating layer (layer A) made of nitrides, carbon nitrides, carbides such as Ti, Cr, Al, and V having a cubic rock salt structure. It has been proposed that a hard coating material having improved hardness and wear resistance through particle refining by suppressing columnar growth of the A layer. [Japanese Patent Laid-Open No. 2005-213637] That is, between the hard coating layer (A layer) having a cubic rock salt structure, a hard coating layer (B layer) having a non-rock salt structure having a different crystal structure is inserted into a hard coating layer (A In order to improve the hardness and abrasion resistance of the film by inhibiting the continuous crystal growth of the layer) to obtain the effect of miniaturizing the particles. In order to achieve this purpose, the thickness of the A layer is 2 to 200 nm, the thickness of the B layer is 0.5 nm or more (preferably 1 nm or more), and the B layer is in a range of 1/2 or less of the A layer thickness. It suggests technical conditions that need to be controlled. However, Japanese Laid-Open Patent Publication No. 2005-213637 considers only the hardness improvement due to particle refinement by depositing film layers having different crystal structures, and the interfacial transition region between the two phases is widened by the bias voltage applied during the deposition process. It is possible to reduce the hardness value, and in particular, no consideration has been given to the structural stability at high temperatures and the change in hardness according to the fact that the interfacial transition between the two phases is more active under high temperature conditions.

Therefore, in order to solve the problem of the TiAlN / BN multilayer thin film proposed by Veprek and Yamamoto, the present inventors, in stacking two or more thin film units consisting of the TiAlN film layer and the BN film layer, the thickness control of the TiAlN film layer and the BN film layer, in particular the BN film layer By reducing the thickness of the thin film below the threshold and optimizing the thickness control of the thin film unit at the same time, the particle size and compressive stress of TiAlN crystalline caused by the bias voltage applied in the deposition process to greatly improve the hardness, from room temperature to 900 ℃ We propose a new surface coating material that minimizes the interfacial transition area between two phases even at high and low temperature conditions to achieve the effect of improving hardness by particle refinement.

Accordingly, an object of the present invention is to provide a TiAlN / BN multilayer hard thin film having improved hardness and thermal stability at the same time.

In order to achieve the above object, the rigid multilayer thin film having excellent thermal stability according to the present invention is a TiAlN film layer having a thickness of 1 to 10 nm, and BN having a thickness of 0.3 to 1.1 nm. It is a multilayer thin film in which two or more units composed of a film layer are laminated, and the thickness of the unit is adjusted to 1.3 to 11.1 nm.

The present invention will be described in more detail as follows.

When two different layers are repeatedly stacked and deposited as a multilayer thin film, a thin but mixing region necessarily exists between the two layers. In the case of the TiAlN / BN multilayer thin film according to the present invention, the dislocation movement between the two layers is suppressed by making the width of the mixing region present at the interface between the two layers as thin as possible at room temperature as well as around 900 ° C. In order to achieve the effect of increasing the physical properties such as hardness at high temperatures.

To this end, in the present invention, by adjusting the thickness of each TiAlN film layer and BN film layer and the thickness control of the unit consisting of these two layers to realize a more optimal microstructure to improve the physical properties such as hardness. As mentioned above, the interfacial structure between the two phases is widened by the bias voltage applied to the base material, the substrate, etc. during the deposition process, thereby reducing the hardness value. In the present invention, however, the microstructure of the TiAlN layer, which is a crystalline phase, is controlled by a bias voltage applied during the deposition process, thereby inducing particle size reduction, compressive stress, and the like, thereby increasing the hardness, thereby increasing the hardness of the transition region between the two phases. It was developed with the understanding that offsetting the decrease sufficiently, and that this increased hardness can also be maintained or even higher by sharp interfacial transitions between the two phases even at high temperatures.

In the present invention, the TiAlN film layer and BN In repeatedly stacking the film layers alternately, the BN film layer is adjusted to a thickness of 1.1 nm or less to have the same lattice structure as that of the TiAlN film layer, thereby improving hardness, and during phase deposition by phase separation at a high temperature of about 900 ° C. The formed interfacial structure can be sharply compositionally sharp, so that thermal stability at high temperature is secured through the transition of the interfacial structure at such a high temperature, thereby obtaining an effect of improving physical properties such as hardness.

The atomic number ratio of titanium (Ti) and aluminum (Al) in the TiAlN film layer constituting the thin film unit, which is a structural unit of the hard multilayer thin film for surface coating according to the present invention, is possible in all composition ranges from 100: 0 to 0: 100. Do. That is, it may be a Ti _1-x Al _x N film layer (0 ≦ _x ≦ 1). However, if the Al content in the TiAlN metal atoms is too small, the oxidation resistance effect is reduced, and if too much, the hardness value decreases. Therefore, the effective atomic ratio of titanium (Ti) and aluminum (Al) in the TiAlN film layer Silver is preferably 60:40 to 40:60. Most preferably, the atomic number ratio of titanium (Ti) and aluminum (Al) is about 50:50. The content of the nitrogen (N) component constituting the TiAlN film layer on the nitride is in the range of 45 to 51 wt% in the total composition.

In the thin film unit constituting the hard multilayer thin film of the present invention, the thickness of the TiAlN film layer is adjusted to be in the range of 1 to 10 nm, preferably in the range of 1 to 4 nm, and the thickness of the BN film layer is in the range of 0.3 to 1.1 nm, Preferably it is adjusted to the range of 0.3 to 0.8 nm. If the thickness of the TiAlN film layer and the BN film layer is too thin, it becomes difficult to form a distinct multilayer structure. In the case of the TiAlN film layer, when the thickness is thick, the hardness may be lowered due to continuous growth of particles, and in the case of the BN film layer, the thickness is BN. The hardness of the phase may decrease as the fraction of the phase increases and no longer matches the TiAlN layer.

In addition, when considering the thickness of each of the TiAlN film layer and the BN film layer as described above, the thickness of the thin film unit, that is, the period is preferably adjusted to the range of 1.3 nm to 11.1 nm, preferably 1.3 to 4.8 nm.

In addition, the overall thickness of the multilayer thin film formed by laminating one or more thin film units as described above is generally in the range of 0.5 to 10 μm.

The thin film unit constituting the multilayer thin film according to the present invention includes one TiAlN film layer, that is, one Ti _1-x Al _x N film layer and one BN film layer, which has enhanced aluminum (Al) content to improve oxidation resistance and thermal stability. . Therefore, the term "thin film unit" in the present specification is defined as referring to a combination consisting of two layers of thin films consisting of one layer of TiAlN film and one layer of BN film. The thin film unit may control the number of units to be stacked according to the thickness of the entire hard thin film, one or more thin film units may be stacked, and as needed, the thin film units may be stacked up to several thousand layers or more. .

In the rigid multilayer thin film according to the present invention, the hardness and toughness values of the entire coating layer were higher than that of a single TiAlN film layer or a single BN film layer in the entire range of Al content of the multilayer thin film according to the present invention. In particular, since the hardness value tends to be maintained at the same level as the hardness value immediately after the deposition even at a high temperature of 900 ° C or rather increases, it is possible to provide a coating layer that can control various hardness, toughness and high temperature properties of a desired shape. Do.

Although the method for forming the multilayer thin film according to the present invention is not particularly limited, in order to form a TiAlN hard film having a high Al atomic ratio and to precisely control the thickness of the BN layer so as to increase wear resistance and heat resistance, the PVD method (physical vapor deposition method) It is preferable to form. As a PVD method, it can deposit by a metal target, AIP (ion framing) method, and reactive sputtering method using magnetron sputtering. In this case, it is also possible to deposit by sputtering using a nitride target instead of a metal target. It may be deposited by ionized metal plasma (IMP) deposition, electron beam deposition, or the like.

Multilayer thin film according to the present invention is characterized in that the TiAlN film layer and the BN film layer is alternately stacked, as a method for forming an alternately stacked structure, as shown in Figure 1 is equipped with two targets Using an unbalanced magnetron sputtering device, one of the two targets is made of TiAl alloy capable of controlling aluminum content, the other is made of BN, and the TiAlN film and BN are revolved by revolving the jig of the jig system 3. It is possible to form multilayer thin films in which films are alternately repeatedly deposited.

The present invention as described above will be described in more detail based on the following examples, but the present invention is not limited to these examples.

EXAMPLE

Examples 1-5 and Comparative Examples 1-4

As shown in FIG. 1, two targets were coated using an unbalanced magnetron sputtering apparatus facing each other. One target of the device was a TiAl alloy capable of controlling aluminum content, and the other was BN. The content of aluminum in the TiAl target was 50 atomic percent.

Coatings were made using DC target power on a substrate polished to 1 μm diamond paste of SKH 9 (AISI M2) high speed tool steel with Vickers hardness value of 631 HRC. At this time, a vacuum inside the chamber was obtained up to a base pressure of 1.0 ㅧ 10 ^-6 torr or less, and then -500 V was applied to the substrate for 30 minutes to clean the substrate using Ar plasma. , TiAl buffer layer (TiAl buffer layer), TiAlN base layer (TiAlN base layer), TiAlN / BN multilayers were deposited in this order. Argon and nitrogen were used to adjust the pressure of the reaction gas in the chamber during deposition to 2 to 8 mtorr, while applying a bias voltage of -120 V to the substrate while maintaining the substrate temperature at 350 ° C., while the revolution speed was 1.5. Rotation was constant at rpm. In order to manufacture the thin film of Example 1, the power applied to the TiAlN target was adjusted to 50W while the power applied to the BN target was fixed at 150W. In order to produce a thin film in which the thickness of the BN film layer is changed while the thickness of the TiAlN film layer is constant at 2.7 nm, the power applied to the TiNN target is 300 W, and the power applied to the BN target is 30 W (Example 2), respectively. 50W (Example 3), 100W (Example 4), 150W (Example 5), 200W (Comparative Example 1), and 300W (Comparative Example 2) were adjusted. In order to manufacture a thin film in which the thickness of the TiAlN film layer is thick to 10.3 nm and the thickness of the BN film layer is changed, the BN power is increased while the thickness of the TiAlN layer is increased by a shutter opening and closing operation in front of the target under a TiAlN target power of 300 W. 50W (comparative example 3) and 300W (comparative example 4) were adjusted.

Thus, the thickness (cycle) of the thin film unit composed of one layer of TiAlN film and one layer of BN film having various thicknesses was 1.7 nm (Example 1), 3.1 nm (Example 2), and 3.3 nm (Example 3), respectively. , 3.5 nm (Example 4), 3.8 nm (Example 5), 4.1 nm (Comparative Example 1), 4.7 nm (Comparative Example 2), 10.9 nm (Comparative Example 3), 12.3 nm (Comparative Example 4) It was. These thin film units were stacked to deposit a thickness of approximately 1.5 μm.

As a result, Ti _0.5 Al _0.5 N / BN Multilayer thin films of composition were obtained. Among them, a cross-sectional TEM image of a multilayer thin film having a periodic value of 3.3 nm is shown in FIG. 2. In the image of FIG. 2, the bright part represents the BN film layer and the dark part represents the TiAlN film layer, and it can be seen that the thin film is repeatedly deposited to a nano-thickness.

In addition, TiAlN single film and BN single film were prepared as comparative examples, and the deposition was performed under the same conditions using the same apparatus as in the above embodiment except that the coating was performed without rotation of the jig equipped with the base material. It was. Since no revolution, a TiAlN single film formed by depositing a single TiAlN and a BN single film formed by depositing a single BN were obtained, respectively.

Experimental Example 1 Measurement of Hardness

The results of measuring the hardness of the thin films prepared according to the Examples and Comparative Examples are shown in Table 1 below.

division Membrane layer Thickness of film layer (nm) Unit thickness (cycle) (nm) Overall thickness of the film (μm) Hardness (GPa) Example 1 TiAlN 1.3 1.7 1.5 38.9 BN 0.4 Example 2 TiAlN 2.7 3.1 1.5 39.2 BN 0.4 Example 3 TiAlN 2.7 3.3 1.5 37.3 BN 0.6 Example 4 TiAlN 2.7 3.5 1.5 35.6 BN 0.8 Example 5 TiAlN 2.7 3.8 1.5 34.7 BN 1.1 Comparative Example 1 TiAlN 2.7 4.1 1.5 24.4 BN 1.4 Comparative Example 2 TiAlN 2.7 4.7 1.5 21.9 BN 2.0 Comparative Example 3 TiAlN 10.3 10.9 1.5 35.2 BN 0.6 Comparative Example 4 TiAlN 10.3 12.3 1.5 19.3 BN 2.0 TiAlN Single Film 1.5 34.9 BN monolayer 1.5 14.8

When comparing the TiAlN / BN multilayer thin films prepared in Examples and Comparative Examples with a single layer, the hardness value of the multilayer thin film was changed in hardness as the microstructure was changed by the insertion and thickness control of the BN film layer. Able to know. The TiAlN / BN multilayer thin films showed increased results compared to the hardness value of the BN single layer, and the multilayer thin films (Examples 1 to 5) in which the thickness of the BN film layer was adjusted to 0.8 nm or less improved than the hardness value of the TiAlN single layer. Indicated.

Figure 3 shows a high resolution TEM (HRTEM) image of the cross section of the specimen prepared in Example 3. When the thickness of the relatively bright BN film layer is as thin as 0.6 nm, the BN film layer has an epitaxial relationship with the relatively dark TiAlN film layer, thereby forming a lattice fringe through the two layers. It can be seen that the BN film layer has the same lattice structure as the TiAlN film layer. This increase in the hardness of the TiAlN / BN multilayer thin films obtained by repeatedly inserting the BN film layer in the TiAlN film layer is apparent when the BN film layer has an epitaxial relationship with the TiAlN film layer, which is significant when the thickness of the BN film layer is below the threshold. It becomes prominent at.

When the thickness of the BN film layer is more than 1.4 nm (Comparative Examples 1, 2, 4), it can be seen that the hardness value is lower than that of the TiAlN single film, which is due to the increase of the fraction of the low hardness (14.8 GPa) BN phase (increase in thickness). Therefore, it is believed that the BN phase no longer has an epitaxial relationship with TiAlN and is present as an independent phase structure. In Comparative Example 1, 2 and 4 in Table 1, the actual measured hardness value is lower than 24.8 which is a simple mixed hardness value ((34.9 + 14.8) / 2) of the TiAlN single layer and the BN single layer. Comparing the hardness of the TiAlN / BN multilayer thin films of Examples 2 to 5, the hardness tends to increase as the thickness (cycle) of the thin film unit becomes thinner. These results show that the hardness is greatly improved by the effect of inhibiting the transition of the dislocation of the interface by repeated lamination.

Comparative Examples 3 and 4 confirmed the change in hardness value according to the thickness of the TiAlN film layer. Compared with Comparative Example 3 and Example 3 or Comparative Example 4 and Comparative Example 2, the thickness of the BN film layer is the same and the thickness of the TiAlN film layer is large, it can be seen that the hardness value is reduced. In other words, even if the TiAlN film layer compensating for the hardness value, if the thickness is too thick, even if the thin BN film layer is repeatedly inserted, the hardness improvement effect is insignificant. It was confirmed that the hardness is significantly reduced compared to the membrane. Therefore, in order to improve the hardness of the multilayer thin film, it is important to adjust the thickness of the BN film layer to be less than the threshold value, but it is preferable to adjust the thickness of the TiAlN film layer to 10 nm or less.

In addition, Example 1 is a result of determining the lower limit of the TiAlN film layer thickness, even if the thickness of the TiAlN film layer is relatively thin to 1.3 nm and the thickness of the BN film layer is adjusted to 0.4 nm, the hardness value of the thin film is about 38.9 GPa. It was found to be superior to the hardness value (34.9 GPa). Therefore, it can be seen that the TiAlN film layer may have an effect of increasing hardness in the present invention if the thickness of the TiAlN film layer is more than the thickness that can maintain the actual crystalline rock salt structure.

Experimental Example 2: Measurement of Thermal Stability

1) change of microstructure

Each specimen prepared in Examples and Comparative Examples was subjected to heat treatment at high temperature to examine stability against heat treatment. The heat treatment was carried out at 600 ℃, 700 ℃, 800 ℃, 900 ℃ for 1 hour each with four specimens corresponding to each embodiment in an N ₂ atmosphere, the change of microstructure by X-ray after heat treatment (1st low intensity change of the angle peak) was measured. The results are shown in Table 2 below.

The values in Table 2 below represent the relative intensity ratios of the low angle peaks according to the temperatures of the specimens heat-treated as described above (relative ratios of the strengths of the specimens before the heat treatment were set to "1"). .

division Thin film unit thickness (cycle) (nm) Low angle peak intensity Before heat treatment 600 ℃ 700 ℃ 800 ℃ 900 ℃ Example 1 1.7 One 1.8 2.3 2.7 2.1 Example 2 3.1 One 2.4 3.9 6.3 3.5 Example 3 3.3 One 3.2 4.6 8.1 5.3 Example 4 3.5 One 4.0 5.5 8.2 3.1 Example 5 3.8 One 2.0 2.7 2.6 2.0 Comparative Example 1 4.1 One 2.8 2.6 4.9 1.8 Comparative Example 2 4.7 One 4.1 5.7 4.4 2.9

As shown in Table 2, the specimen produced according to Examples 1 to 4 can be seen that the relative strength gradually increases as the heat treatment temperature is increased to 800 ℃. The intensity of the low angle XRD peak is lower as the mixed layer between two different layers becomes thicker. It can be seen that the thickness of the thinner. In other words, compositional sharpness was obtained.

2) change in hardness

Each specimen prepared in Examples and Comparative Examples was subjected to heat treatment at high temperature to examine stability against heat treatment. Heat treatment was carried out at 600 ℃, 700 ℃, 800 ℃ and 900 ℃ with three specimens for 1 hour in N ₂ atmosphere, the hardness change after the heat treatment was measured. The results are shown in Table 3 below.

division Thin film unit thickness (cycle) (nm) Hardness value (GPa) Before heat treatment 600 ℃ 700 ℃ 800 ℃ 900 ℃ Example 1 1.7 38.9 39.7 41.9 40.3 39.5 Example 2 3.1 39.2 41.3 43.8 40.2 39.7 Example 3 3.3 37.3 38.7 44.5 37.4 36.6 Example 4 3.5 35.6 38.6 36.3 35.8 36.0 Example 5 3.8 34.7 34.9 35.2 34.8 34.0 Comparative Example 1 4.1 24.4 29.0 27.2 26.4 26.1 Comparative Example 2 4.7 21.9 19.3 18.0 17.1 16.6 TiAlN Single Film 34.9 33.1 32.7 31.6 29.2

As shown in Table 3, in the case of the specimens according to Examples 1 to 5 it can be seen that the hardness is improved as the heat treatment temperature increases up to 700 ℃, the specimens of Examples 1, 2 and 4 are 800 ℃, 900 ℃ heat treatment Even when the temperature is lower than the specimen heat-treated at 700 ℃ it can be seen that it maintains more than the hardness value during deposition. On the other hand, in the case of the specimens according to Examples 3 and 5, the hardness value at 900 ℃ heat treatment is lower than at room temperature, but the rate of decrease is only about 2%. Therefore, it can be seen that the TiAlN / BN thin film of the present invention not only improves the hardness value by the introduction of the BN film layer, but also maintains the increased hardness value until 900 ° C. heat treatment. In contrast, the hardness of the BN film layer was 2.0 nm and the thickness of the relatively thick specimens (Comparative Example 2) and TiAlN single layer decreased with increasing heat treatment temperature. It decreased to about 76% and 84% at room temperature. Thus, it can be seen that the thickness of the BN film layer should be controlled below the critical thickness (<2.0 nm) in order to significantly improve the thermal stability of the hardness value by implementing the nano multilayer structure by introducing the BN film layer.

Overall, in order to obtain a TiAlN / BN nano multilayer structure coating material having excellent hardness and thermal stability, the thickness of the BN film layer should be adjusted to 1.1 nm or less (preferably 0.8 nm or less).

The meaning of the above experimental results have the following importance. In general, properties required for coating materials such as various mechanical parts, gold strings, cutting tools, and the like include hardness, toughness, high temperature stability, and oxidation resistance. Among these, when the use environment is a high temperature, thermal stability at a high temperature is the most important factor, and it is necessary to maintain physical properties at room temperature even at a high temperature. TiAlN / BN presented in the present invention In the case of multi-layer coated thin film, the hardness value can be better than that of TiAlN single layer by controlling the fine structure. Also, it maintains the hardness value at room temperature even up to 900 ℃, so it is excellent in thermal stability. It can be usefully used as a coating material for cutting tools.

Therefore, when the multilayer thin film according to the present invention is coated on the surface, the hardness, toughness and thermal stability of the coating layer is remarkably improved, and thus the effect that can be widely applied to improve the surface strength of cutting tools, molds and various mechanical parts is improved. have.

Claims (3)

1-10 nm thick TiAlN film layer, 0.3-0.8 nm thick BN A multi-layered thin film having excellent thermal stability, characterized in that the multi-layered thin film of two or more units composed of a film layer, the period of the thickness of the unit is adjusted to 1.3 to 10.8 nm. The method of claim 1, TiAlN film layer 1-4 nm thick, BN 0.3-0.8 nm thick Hard multilayer thin film having excellent thermal stability, characterized in that the multi-layered thin film of two or more units composed of a film layer, the period of the thickness of the unit is adjusted to 1.3 to 4.8 nm. The method according to claim 1 or 2, The TiAlN film layer is a rigid multilayer thin film having excellent thermal stability, characterized in that the atomic number ratio of titanium (Ti) and aluminum (Al) is 60:40 to 40:60.

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