TWI437109B - Hard coating and method for manufacturing the coating and articles coated with the coating - Google Patents

Description

Hard coating, preparation method thereof and coated member having the same

The invention relates to a PVD hard coating, a preparation method thereof and a coated member having the same.

The coating process has a wide range of applications in the industrial field. Among them, the coating of TiN film on the surface of the tool or mold can greatly improve the service life of the tool and the mold. However, as metal cutting processes progress toward high cutting speeds, high feed rates, high reliability, long life, high precision, and good cutting control, higher demands are placed on the performance of surface coatings. TiN coatings have gradually failed to meet further demands in terms of hardness, wear resistance, and oxidation ablation.

The addition of metal elements such as Cr and Al to the TiN coating can further improve the hardness and oxidation resistance. The hardness and high temperature oxidation resistance of the TiAlN coating are greatly improved compared with the TiN coating, which is the most commonly used. Tool coating material. However, the ordinary TiAlN coating has an HV hardness of 30±5 GPa and an oxidation resistance temperature of 800° C., and it has not been able to satisfactorily meet the high-speed cutting of difficult-to-machine materials such as stainless steel. Increasing the Al content in the TiAlN coating can improve the hardness and oxidation resistance of the coating. However, the excessive Al content causes a sharp drop in the mechanical properties of the coating.

In view of this, it is necessary to provide a high temperature oxidation resistance, wear resistance, hardness High hard coating.

In addition, it is necessary to provide a method of preparing the above hard coat layer.

It is also necessary to provide a covering having the above hard coating.

A hard coating layer consisting of a transition layer, an intermediate layer and an outermost layer which are sequentially formed on a hard substrate, the transition layer being composed of Ti-Nb-N three components, the intermediate layer and the outermost layer are all Ti -Si-Nb-N four-component composition, the atomic percentage of Ti atom and Nb in the outermost layer is smaller than the atomic percentage of Ti atom and Nb in the intermediate layer, respectively, and the percentage of Si atom in the outermost layer is larger than the middle The percentage of Si atom in the layer, the percentage of Ti atoms in the intermediate layer is 35~45%, the atomic percentage of Nb is 2~5%, the percentage of Si atom is 20~30%, and the content of N atom is It is 28~36%.

A method for preparing a hard coating comprises the steps of: placing a substrate to be plated in an arc ion coating machine, and placing the titanium-bismuth alloy target and the pure tantalum target at an arc source position of the arc ion coating machine; After vacuuming the vacuum chamber of the ion coating machine, argon gas and reaction gas nitrogen are introduced, the bias voltage is adjusted to -200~-400V, the titanium ruthenium target is turned on, and the target current of the titanium ruthenium is adjusted to 50-80 A to deposit a substrate on the substrate. The transition layer consisting of Ti-Nb-N three components; adjusting the bias voltage to -150~-250V, adjusting the target current of the titanium-niobium alloy to 70~100A, simultaneously opening the target, adjusting the target current to 40~60A, Forming an intermediate layer composed of Ti-Si-Nb-N four-component element on the transition layer; adjusting the target current of the titanium-niobium alloy to 40-60A, and adjusting the target current of the yttrium to 70-100A to deposit on the intermediate layer An outermost layer composed of four components of Ti-Si-Nb-N, wherein the atomic percentage of Ti atoms and Nb in the outermost layer is smaller than that of Ti atoms and Nb atoms in the intermediate layer, respectively. The percentage of Si in the outermost layer is greater than the percentage of Si atom in the intermediate layer.

A covering member comprising a hard substrate and a hard coating formed on the substrate, the hard coating layer being composed of a transition layer, an intermediate layer and an outermost layer sequentially formed on the substrate, the transition layer being Ti-Nb-N The three-component composition, the intermediate layer and the outermost layer are composed of Ti-Si-Nb-N four-component, the atomic percentage of Ti atom and Nb in the outermost layer is smaller than the atomic percentage of Ti atom and Nb in the intermediate layer, respectively. The content of the Si atom in the outermost layer is greater than the Si atom percentage of the intermediate layer, the Ti atom percentage in the intermediate layer is 35 to 45%, and the Nb atomic percentage is 2 to 5%, Si atom The percentage is 20~30%, and the N atom percentage is 28~36%.

Compared with the prior art, the transition layer of the hard coating directly bonded to the substrate has a higher content of Ti atoms and Nb atoms, and the coating layer is mainly TiNbN phase, and TiNbN has a hard surface with high speed steel, hard alloy, cermet, etc. The matrix material matches a good thermal expansion coefficient, so the internal stress at the interface is small, and the interface is excellent; the outermost layer of the hard coating has a high content of germanium atoms, the coating is mainly composed of SiN phase, the hardness of SiN is high, and the thermal conductivity is low. Moreover, it has good high-temperature lubricity; and because Nb element is contained in the entire hard coating layer, Nb has excellent plasticity and a high melting point, so that the toughness and wear resistance of the hard coating layer can be improved.

10‧‧‧hard coating

11‧‧‧Transition layer

13‧‧‧Intermediate

15‧‧‧ outermost layer

20‧‧‧ base

30‧‧‧Covered parts

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a cross-sectional view showing a coated member having a hard coat layer in accordance with a preferred embodiment of the present invention.

The term "atomic percent" as used in the present invention refers to the content percentage of atoms.

Referring to FIG. 1, a hard coat layer 10 of a preferred embodiment of the present invention is formed in a rigid manner. The transition layer 11, the intermediate layer 13, and the outermost layer 15 on the base 20 are formed. The base 20 may be high speed steel, cemented carbide, cermet or the like.

The transition layer 11 is directly deposited on the surface of the substrate 20. The transition layer 11 is composed of Ti-Nb-N three components, wherein the percentage of Ti atoms is about 50-60%, and the atomic percentage of Nb is about 4-6. %, N atomic percentage is about 35~45%. In the present embodiment, the transition layer 11 has a Ti atomic percentage of 55%, an Nb atomic percentage of 5%, and an N atomic percentage of 40%.

The intermediate layer 13 is formed directly on the transition layer 11. The intermediate layer 13 is composed of Ti-Si-Nb-N four components, wherein the percentage of Ti atoms is about 35 to 45%, the atomic percentage of Nb is about 2 to 5%, and the percentage of Si atoms is about 20~. 30%, N atomic percentage is about 28~36%. In the present embodiment, the intermediate layer 13 has a Ti atomic percentage of 40%, an Nb atomic percentage of 3%, a Si atomic percentage of 25%, and an N atomic percentage of 32%.

The outermost layer 15 is formed directly on the intermediate layer 13. The outermost layer 15 is also composed of a Ti-Si-Nb-N four-component, which is different from the intermediate layer 13 in that the atomic percentage of Ti atoms and Nb in the outermost layer 15 is smaller than that of the Ti and Nb atoms in the intermediate layer 13, respectively. The percentage of Si atomic percentage in the outermost layer 15 is greater than the Si atomic percentage of the intermediate layer 13. In the outermost layer 15, the percentage of Ti atoms is about 15 to 25%, the atomic percentage of Nb is about 0.5 to 2.5%, the percentage of Si atoms is about 40 to 55%, and the percentage of N atoms is about 28~. 36%. In the present embodiment, the outermost layer 15 has a Ti atom percentage of 20%, an Nb atomic percentage of 2%, a Si atomic percentage of 45%, and an N atomic percentage of 33%.

The overall thickness of the hard coat layer 10 is about 1 to 8 μm, preferably 3 to 5 μm. Wherein, the thickness of the transition layer 11 is approximately 30-60 nm, and the thickness of the intermediate layer 13 is approximately a hard coating. 10 overall thickness of 85~95%, the outermost layer 15 thickness is about 20~30nm. The hard coating 10 has a microhardness of 40 GPa or more.

The transition layer 11 directly bonding the hard coating layer 10 and the substrate 20 has a high content of Ti atoms and Nb atoms, and the coating layer is mainly TiNbN phase, and the TiNbN has a good matching with the matrix material of the high speed steel, the hard alloy, the cermet and the like. The coefficient of thermal expansion is such that the internal stress at the interface is small and the interface is excellent; the outermost layer 15 of the hard coating 10 has a high content of germanium atoms, the coating is mainly composed of SiN phase, the hardness of SiN is high, the thermal conductivity is low, and The high-temperature lubricity is preferred; and since the Nb element is contained in the entire hard coat layer 10, Nb has excellent plasticity and a high melting point, so that the toughness and wear resistance of the hard coat layer 10 can be improved.

Referring to FIG. 1, the covering member 30 having the hard coating layer 10 includes the hard substrate 20 and a hard coating layer 10 formed on the substrate 20. The covering member 30 can be various types of cutting tools, precision measuring tools, and molds. The base body 20 may be a high-hardness material such as high-speed steel, cemented carbide, cermet, ceramic, or sintered diamond. The hard coat layer 10 has the features described above.

The hard coat layer 10 described above is mainly synthesized by arc ion plating of titanium, tantalum, niobium and nitrogen. The preparation method of the hard coating layer 10 mainly includes the following steps:

(1) Surface chemical ultrasonic cleaning of the substrate 12 is carried out, that is, the substrate 20 is placed in an ultrasonic cleaner containing an ethanol and/or acetone solution for vibration cleaning to remove impurities and oil on the surface of the substrate, and the cleaning is completed. After drying, spare. The material of the base body 20 may be high speed steel, hard alloy, cermet ceramic, sintered diamond or the like.

(2) placing the above-mentioned cleaned substrate 20 in an arc ion plating machine to remove titanium The alloy target is placed at an arc source position of the arc ion coater at a distance from the pure tantalum target. The weight of niobium in the titanium-niobium alloy target is 7-10%, and the balance is titanium.

(3) evacuating the vacuum chamber of the arc ion coating machine to a level of 10 ^-3 Pa (3.0 × 10 ^-3 Pa in this embodiment), and introducing a flow rate of 300 sccm (standard state ML / min) of high-purity argon gas, and The reaction gas nitrogen gas having a flow rate of 280 to 300 sccm is introduced to make the pressure in the vacuum chamber reach 0.1 to 2 Pa. The nitrogen flow rate is preferably 290 sccm. Adjust the bias voltage to -200~-400V. The titanium-niobium alloy target is turned on, and the titanium-niobium alloy target current is adjusted to 50-80 A to deposit the Ti-Nb-N transition layer 11 on the substrate 20, and the deposition time is 5 to 10 minutes.

(4) Then, adjust the bias voltage to -150~-250V, adjust the target current of titanium-niobium alloy to 70~100A, simultaneously open the target, adjust the target current to 40~60A, and control the deposition time to 30~60 minutes. The Ti-Si-Nb-N intermediate layer 13 is formed on the transition layer 11.

(5) Adjusting the target current of the titanium-niobium alloy to 40~60A, adjusting the target current of the crucible to 70~100A, and depositing time for 3~5 minutes to deposit the outermost layer of the Ti-Si-Nb-N on the intermediate layer 13 Thus, the hard coat layer 10 is formed on the substrate 20. The hard coat layer 10 has the features described above.

(6) Turn off the negative bias voltage and the target of the titanium-niobium alloy target and the target, stop the introduction of argon and nitrogen. After the hard coating is cooled, the air is introduced into the vacuum chamber, the vacuum chamber door is opened, and the plating is removed. The base.

It can be understood that the preparation method of the above hard coating layer 10 may further include ion cleaning the plating substrate in the arc ion coating machine before depositing the coating layer.

10‧‧‧hard coating

11‧‧‧Transition layer

13‧‧‧Intermediate

15‧‧‧ outermost layer

20‧‧‧ base

30‧‧‧Covered parts

Claims (14)

A hard coating layer comprising a transition layer, an intermediate layer and an outermost layer which are sequentially formed on a rigid substrate, wherein the transition layer is composed of Ti-Nb-N three components, and the intermediate layer and the outermost layer are composed of Ti-Si-Nb-N four-component composition, the atomic percentage of Ti atom and Nb in the outermost layer is smaller than the atomic percentage of Ti atom and Nb in the intermediate layer, respectively, and the percentage of Si atom in the outermost layer is larger than the The atomic percentage of Si in the intermediate layer, the percentage of Ti atoms in the intermediate layer is 35 to 45%, the percentage of Nb atoms is 2 to 5%, and the percentage of Si atoms is 20 to 30%, and the percentage of N atoms is The content is 28~36%. The hard coating layer as claimed in claim 1, wherein the transition layer has a percentage of Ti atoms of 50 to 60%, a percentage of Nb atoms of 4 to 6%, and a percentage of N atoms of 35 to 45. %. The hard coat layer of claim 2, wherein the transition layer has a Ti atomic percentage of 55%, an Nb atomic percentage of 5%, and an N atomic percentage of 40%. The hard coat layer according to claim 1, wherein the intermediate layer has a Ti atom content of 40%, a Nb atom percentage of 3%, a Si atom percentage of 25%, and an N atomic percentage. The content is 32%. The hard coating layer according to claim 1, wherein the outermost layer has a Ti atom content of 15 to 25%, a Nb atom percentage of 0.5 to 2.5%, and a Si atom percentage of 40. 55%, N atomic percentage is 28~36%. The hard coat layer according to claim 5, wherein the outermost layer has a Ti atom percentage of 20%, a Nb atom percentage of 2%, a Si atom percentage of 45%, and an N atomic percentage. The content is 33%. The hard coat layer according to claim 1, wherein the hard coat layer has a thickness of 1 to 8 μm, wherein the thickness of the transition layer is 30 to 60 nm, and the thickness of the intermediate layer is the overall thickness of the hard coat layer. 85 to 95% of the degree, the outermost layer has a thickness of 20 to 30 nm. A method for preparing a hard coating comprises the steps of: placing a substrate to be plated in an arc ion coating machine, and placing the titanium-bismuth alloy target and the pure tantalum target at an arc source position of the arc ion coating machine; After vacuuming the vacuum chamber of the ion coating machine, argon gas and reaction gas nitrogen are introduced, the bias voltage is adjusted to -200~-400V, the titanium ruthenium target is turned on, and the target current of the titanium ruthenium is adjusted to 50-80 A to deposit a substrate on the substrate. The transition layer consisting of Ti-Nb-N three components; adjusting the bias voltage to -150~-250V, adjusting the target current of the titanium-niobium alloy to 70~100A, simultaneously opening the target, adjusting the target current to 40~60A, Forming an intermediate layer composed of Ti-Si-Nb-N four-component element on the transition layer; adjusting the target current of the titanium-niobium alloy to 40-60A, and adjusting the target current of the yttrium to 70-100A to deposit on the intermediate layer An outermost layer composed of four components of Ti-Si-Nb-N, wherein the atomic percentage of Ti atoms and Nb in the outermost layer is smaller than the atomic percentage of Ti atoms and Nb in the intermediate layer, respectively, and the Si atom in the outermost layer The percentage is greater than the Si atomic percentage of the intermediate layer. The method for preparing a hard coat layer according to claim 8, wherein the weight ratio of ruthenium in the titanium-niobium alloy target is 7 to 10%. The method for preparing a hard coat layer according to claim 8, wherein the vacuum chamber has a vacuum degree of 10-3 Pa after vacuuming; the flow rate of the argon gas is 300 sccm, and the nitrogen gas is introduced. The flow rate is 280~300sccm. The method for preparing a hard coat layer according to claim 8, wherein the deposition time of the transition layer is 5 to 10 minutes; the deposition time of the intermediate layer is 30 to 60 minutes; and the deposition time of the outermost layer is 3 ~5 minutes. A covering member comprising a hard substrate and a hard coating layer formed on the substrate, the hard coating layer being composed of a transition layer, an intermediate layer and an outermost layer formed on the substrate in sequence, wherein the transition layer is composed of Ti -Nb-N three-component composition, the intermediate layer and the outermost layer are all Ti-Si-Nb-N a four-component composition, wherein the atomic content of Ti atoms and Nb in the outermost layer is smaller than the atomic percentage of Ti atoms and Nb atoms in the intermediate layer, respectively, and the percentage of Si atoms in the outermost layer is greater than the Si atomic percentage of the intermediate layer The content of the Ti layer in the intermediate layer is 35 to 45%, the atomic percentage of Nb is 2 to 5%, the percentage of Si atoms is 20 to 30%, and the percentage of N atoms is 28 to 36%. The covering member according to claim 12, wherein the covering member is one of a cutting tool, a precision measuring tool and a mold. The coated article of claim 12, wherein the substrate is one of high speed steel, cemented carbide, cermet, ceramic, and sintered diamond.