阅读说明：本技术 一种AlTiN梯度硬质涂层及其制备方法 (AlTiN gradient hard coating and preparation method thereof ) 是由 兰睿 卢国英 石昌仑 于 2020-07-22 设计创作，主要内容包括：本发明公开了一种AlTiN梯度硬质涂层,包括基体,基体的顶部附着有Cr打底层,Cr打底层的顶部附着有CrN过渡层,CrN过渡层的顶部附着有CrN+AlTiN过渡层,CrN+AlTiN过渡层的顶部附着有AlTiN梯度层。本发明还提供了一种AlTiN梯度硬质涂层的制备方法,包括以下步骤：首先在基体上表面采用电弧离子镀沉积Cr打底层；然后在Cr打底层上沉积CrN过渡层,继而在CrN过渡层上沉积CrN+AlTiN过渡层,最后在CrN+AlTiN过渡层上通过改变四个梯度的偏压沉积AlTiN梯度层。本发明的AlTiN涂层具有高的硬度和良好的膜基结合力。因此采用梯度AlTiN涂层,既可以维持AlTiN涂层自身的优点,又提高了膜基结合力。(The invention discloses an AlTiN gradient hard coating, which comprises a substrate, wherein a Cr priming layer is attached to the top of the substrate, a CrN transition layer is attached to the top of the Cr priming layer, a CrN + AlTiN transition layer is attached to the top of the CrN transition layer, and an AlTiN gradient layer is attached to the top of the CrN + AlTiN transition layer. The invention also provides a preparation method of the AlTiN gradient hard coating, which comprises the following steps: firstly, depositing a Cr bottom layer on the upper surface of a substrate by adopting arc ion plating; and then depositing a CrN transition layer on the Cr priming layer, then depositing a CrN + AlTiN transition layer on the CrN transition layer, and finally depositing an AlTiN gradient layer on the CrN + AlTiN transition layer by changing the bias voltage of four gradients. The AlTiN coating has high hardness and good film-substrate binding force. Therefore, the gradient AlTiN coating is adopted, so that the advantages of the AlTiN coating can be maintained, and the film-substrate binding force is improved.)

1. An AlTiN gradient hard coating is characterized in that: the Cr-AlTiN gradient film comprises a substrate, wherein a Cr bottoming layer is attached to the top of the substrate, a CrN transition layer is attached to the top of the Cr bottoming layer, a CrN + AlTiN transition layer is attached to the top of the CrN transition layer, and an AlTiN gradient layer is attached to the top of the CrN + AlTiN transition layer;

cr accounting for 30 to 55 percent of the atomic percentage of each element in the CrN transition layer and N accounting for 45 to 70 percent of the atomic percentage of each element in the CrN transition layer;

in the CrN + AlTiN transition layer, the atomic percent of each element in the CrN is 30-55% of Cr and 45-70% of N; the atomic percentages of the elements in the AlTiN are as follows: 30-40 at.% of Al, 10-20 at.% of Ti and 45-55 at.% of N;

the AlTiN gradient layer comprises the following elements in atomic percentage: 30-40 at.% of Al, 10-20 at.% of Ti and 45-55 at.% of N, wherein the AlTiN gradient layer comprises 4 AlTiN coatings in deposition states, and the deposition bias voltage is 40-60A, 80-100A, 120-140A and 160-180A from bottom to top in sequence.

2. The method for preparing an AlTiN gradient hard coating according to claim 1, wherein: the method comprises the following steps: firstly, depositing a Cr bottom layer on the upper surface of a substrate by adopting arc ion plating; and then depositing a CrN transition layer on the Cr priming layer, then depositing a CrN + AlTiN transition layer on the CrN transition layer, and finally depositing an AlTiN gradient layer on the CrN + AlTiN transition layer by changing the bias voltage of four gradients.

3. The method for preparing an AlTiN gradient hard coating according to claim 2, wherein: the method specifically comprises the following operation steps:

1) the substrate material was set on a rotating holder in a vacuum chamber, and the vacuum chamber was evacuated to a basic pressure of 1.0X 10^-3Heating to 500-700 ℃ below Pa; then, the cavity of the vacuum chamber was filled with Ar having a purity of 99.99% to 1.0X 10^-1-1.0 Pa; starting Ar ion glow discharge, and carrying out plasma etching on the surface of the base material for 30-40 minutes;

2) depositing a transition layer: firstly, carrying out Cr priming layer deposition for 2-5 minutes, and then introducing N₂Igniting the Cr target by gas, setting the arc current to be 60-100A, and carrying out the reaction deposition of the CrN layer for 2-5 minutes; igniting the AlTi target, setting the arc current to be 60-100A, and carrying out reaction deposition on the CrN + AlTiN layer for 2-5 minutes;

3) depositing a gradient layer: closing the Cr target, igniting the AlTi target, adjusting the bias voltage, and depositing the gradient AlTiN coating for 15-30 minutes respectively under the bias voltages of 40-60A, 80-100A, 120-140A and 160-180A in sequence;

4. the method for preparing an AlTiN gradient hard coating according to claim 3, wherein: the alloy targets used in the step 2) and the step 3) are 4 pure Cr targets and 4 AlTi targets, wherein Al: the proportion of the atomic percent of Ti is 60-80%: 20-40%.

Technical Field

The invention belongs to the field of hard coating, and particularly relates to an AlTiN gradient hard coating and a preparation method thereof.

Background

AlTiN isThe novel Ti-based coating developed on the basis of TiN is called AlTiN to be different from TiAlN coating in coating with more Al content, has the characteristics of better hot hardness, high film-substrate binding force, high hardness, high oxidation temperature, small friction coefficient and the like, and is widely applied to the aspects of cutting tools, mold manufacturing, aeroengines, biomedicine and the like at present. The higher Al content ensures that the surface of the AlTiN coating can form compact, complete and continuous Al under the high-temperature condition₂O₃And a protective film, which can improve the high temperature oxidation resistance of the coating. Studies have shown that as the bias increases during deposition, the hardness of the coating increases, but at the same time the residual stress increases. Excessive residual stress can cause cracking of the coating and the substrate, thereby reducing the film-substrate bonding force.

In view of the above, there is a need to design an AlTiN gradient hard coating and a method for preparing the same, which changes the deposition bias by gradient to make the residual stress of the film layer near the substrate smaller and the hardness of the film layer near the surface larger. By reasonable design and the adoption of the gradient AlTiN coating, the advantages of the AlTiN coating can be maintained, and the film-substrate binding force is improved.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide an AlTiN gradient hard coating and a preparation method thereof, so as to overcome the defects in the prior art.

In order to achieve the purpose, the invention provides the following technical scheme:

an AlTiN gradient hard coating is characterized in that: the Cr-AlTiN gradient film comprises a substrate, wherein a Cr bottoming layer is attached to the top of the substrate, a CrN transition layer is attached to the top of the Cr bottoming layer, a CrN + AlTiN transition layer is attached to the top of the CrN transition layer, and an AlTiN gradient layer is attached to the top of the CrN + AlTiN transition layer; cr accounting for 30 to 55 percent of the atomic percentage of each element in the CrN transition layer and N accounting for 45 to 70 percent of the atomic percentage of each element in the CrN transition layer; in the CrN + AlTiN transition layer, the atomic percent of each element in the CrN is 30-55% of Cr and 45-70% of N; the atomic percentages of the elements in the AlTiN are as follows: 30-40% of Al, 10-20% of Ti and 45-55% of N; the AlTiN gradient layer comprises the following elements in atomic percentage: 30-40% of Al, 10-20% of Ti and 45-55% of N, wherein the AlTiN gradient layer comprises 4 AlTiN coatings in deposition states, and the deposition bias voltage is 40-60A, 80-100A, 120-140A and 160-180A from bottom to top in sequence.

The invention also provides a preparation method of the AlTiN gradient hard coating, which is characterized by comprising the following steps: the method comprises the following steps: firstly, depositing a Cr bottom layer on the upper surface of a substrate by adopting arc ion plating; and then depositing a CrN transition layer on the Cr priming layer, then depositing a CrN + AlTiN transition layer on the CrN transition layer, and finally depositing an AlTiN gradient layer on the CrN + AlTiN transition layer by changing the bias voltage of four gradients.

As an optimized technical scheme, the method specifically comprises the following operation steps:

1) the substrate material was set on a rotating holder in a vacuum chamber, and the vacuum chamber was evacuated to a basic pressure of 1.0X 10^-3Heating to 500-700 ℃ below Pa; then, the cavity of the vacuum chamber was filled with Ar having a purity of 99.99% to 1.0X 10^-1-1.0 Pa; starting Ar ion glow discharge, and carrying out plasma etching on the surface of the base material for 30-40 minutes;

2) depositing a transition layer: firstly, carrying out Cr priming layer deposition for 2-5 minutes, and then introducing N₂Igniting the Cr target by gas, setting the arc current to be 60-100A, and carrying out the reaction deposition of the CrN layer for 2-5 minutes; igniting the AlTi target, setting the arc current to be 60-100A, and carrying out reaction deposition on the CrN + AlTiN layer for 2-5 minutes;

3) depositing a gradient layer: closing the Cr target, igniting the AlTi target, adjusting the bias voltage, and depositing the gradient AlTiN coating for 15-30 minutes respectively under the bias voltages of 40-60A, 80-100A, 120-140A and 160-180A in sequence;

as an optimized technical scheme, the alloy targets used in the step 2) and the step 3) are 4 pure Cr targets and 4 AlTi targets, wherein the Al: the proportion of the atomic percent of Ti is 60-80%: 20-40%.

Due to the adoption of the technical scheme, compared with the prior art, the invention has the beneficial effects that:

the AlTiN coating has high hardness and good film-substrate binding force at high temperature. Practice has shown that the higher the deposition voltage, the better the AlTiN hardness and wear resistance. The lower hardness AlTiN coating is deposited near the substrate with a lower voltage, which reduces the hardness difference and stress concentration at the interface, while the AlTiN coating deposited with a higher voltage on the surface in contact with the workpiece has a higher hardness and wear resistance. Therefore, the gradient AlTiN coating is adopted, so that the advantages of the AlTiN coating can be maintained, and the film-substrate binding force is improved.

The invention is further illustrated with reference to the figures and examples.

Drawings

FIG. 1 is a schematic view of the flow principle of the present invention.

FIG. 2 shows the surface morphology of the AlTiN gradient hard coating of the invention.

FIG. 3 is a picture of the adhesion test of the AlTiN gradient hard coating of the present invention.

Detailed Description

This example shows a method for preparing an AlTiN gradient hard coating layer for a cemented carbide milling cutter surface, and it should be noted that the scope of the present invention is not limited to the following examples.