CN102634755B - A kind of dense nitride ceramic coating and preparation method thereof - Google Patents

Abstract

The invention discloses a dense nitride ceramic coating and a preparation method thereof. Firstly, the surface to be treated of a mechanical part is cleaned; then the nitride coating is prepared by a reaction deposition method, and the process of preparing the nitride coating by the reaction deposition method , the bias voltage alternates between high bias and low bias. The nitride ceramic coating has a high hardness of 1700Hv-2600Hv and a low stress of 0.1GPa-1GPa, the grain ratio is 0-0.5, and the grain size is about 10nm-200nm. The coating deposition process of the invention is simple, the deposition rate is high, and the stress is low.

Description

A kind of dense nitride ceramic coating and preparation method thereof

technical field

The present invention relates to surface treatment technology, in particular to a method for preparing a dense nitride coating, especially to a nitride coating for corrosion resistance and diffusion barrier applications.

Background technique

Due to their good hardness, chemical inertness, biocompatibility and resistance to atomic diffusion, transition metal nitride coatings have been widely used in tribology, biomedical, corrosion resistance and electronics industries. However, transition metal nitrides are prone to (111) preferred orientation during the growth process, and the (111) plane of the grains grows rapidly along the normal direction of the coating, resulting in the generation of crisp columnar crystals, which will be detrimental to the hardness and durability of the coating. Enhanced corrosion and diffusion barrier properties. At present, different methods are usually used to inhibit the growth of columnar crystals: adding other elements is an effective method, but the addition of a third component may change the original properties of the coating, and multi-source co-deposition or alloy deposition sources must use special Alloy targets or multi-target co-deposition, which will significantly increase the complexity of the process and increase the cost; increasing the energy of the deposited particles is also a common method, by increasing the coating structure defects, promoting nucleation, refining grains, thereby improving coating density However, this method often brings greater stress, which is not conducive to the bonding performance of the coating, and this method will reduce the coating deposition rate and reduce production efficiency. Therefore, obtaining dense nitride ceramic coatings with high deposition rate and low stress is very important in industrial production and practical application.

Contents of the invention

The invention provides a dense nitride ceramic coating and a preparation method thereof, which can take into account high deposition rate and low stress.

The technical scheme of the present invention is: a preparation method of a dense nitride ceramic coating, which first cleans the surface of the mechanical parts to be treated; then prepares the nitride coating by the reaction deposition method, and prepares the nitride coating by the reaction deposition method During the process, the bias voltage is alternately changed between high bias voltage and low bias voltage.

The high bias voltage is any one of 0~-80V, and the low bias voltage is any one of -80V~-150V; the response time of each bias voltage is 1 minute-10 minutes.

A more preferred solution is: before preparing the nitride coating, first adopt a vapor deposition method to deposit a Ti or Cr intermediate layer with a thickness of 50 nm-200 nm on the surface;

Based on the dense nitride ceramic coating obtained by the preparation method of the dense nitride ceramic coating, the nitride ceramic coating has a higher hardness of 1700Hv-2600Hv and a lower stress of 0.1 GPa-1GPa , the grain ratio is 0-0.5, and the grain size is about 10 nm-200nm.

Beneficial effect:

(1) The deposition process is simple: if the coating density is improved by adding other elements, a special alloy target or multi-target co-deposition must be used, which will complicate the process and increase the cost; and this process is only for the deposition process The bias voltage is periodically adjusted without other complicated processes, and it is easy to improve the original process and improve the coating quality.

(2) High deposition rate: constant high bias deposition, due to the anti-sputtering effect, high-energy particles bombard the surface of the coating, causing some deposited particles to detach from the coating, and the deposition rate of the coating is reduced; while the present invention reduces the high bias deposition time, It is beneficial to increase the coating rate, thereby improving work efficiency and reducing work costs.

(3) Low stress: During the constant high bias deposition process, high-energy particles bombard the coating, resulting in the generation of a large number of defects and a significant increase in stress. When the stress increases to a certain extent, the coating will peel off and fail, even if it is not peeled off, the bonding performance of the coating will decrease significantly, and its application bearing range will decrease. To avoid peeling, the coating thickness must be reduced, which is detrimental to its wear, corrosion and diffusion barrier properties. However, the method of the present invention can take both thickness and stress into consideration because the deposition process of high bias voltage is reduced.

(4) It can be suitable for surface strengthening of precision components, molds/tools and medical devices, and diffusion barriers in microelectronic chips.

Detailed ways

First, the surface to be treated is cleaned by conventional methods; the surface to be treated is placed in a vacuum vapor deposition system and the surface is cleaned by back sputtering. After these two steps, the surface is clean enough to better ensure the coating quality; The nitride coating is then deposited by reactive deposition techniques. During the deposition process, the vacuum deposition parameter - bias voltage - changes periodically between two values, which promotes the uniform spreading of deposited particles on the surface of the nitride coating and increases the density of the coating. The value of the bias voltage alternating parameter is between 0 ~ -80V and -80 V ~ -150V, each of which can take one value; the alternating period is 1 minute to 10 minutes. Deposit to the desired thickness, cool under vacuum, then pass through dry nitrogen, open the vacuum chamber, and obtain a dense nitride coating. The hardness of the nitride ceramic coating is 1700Hv-2600Hv, and the stress is 0.1GPa-1GPa. The preferred orientation consists of two directions [111] and [100], the ratio can be adjusted independently, the grain ratio is 0-0.5, and the grain size is about 10 nm-200 nm.

Before preparing the nitride coating, a 50 nm-200 nm Ti or Cr intermediate layer can be deposited on the treated surface by vapor deposition method, and this step can be omitted according to the actual situation. Because the interlayer is mainly used to increase the coating adhesion, it is not needed in some industries such as microelectronics.

Example 1

A method for preparing a TiN diffusion barrier layer for dense integrated circuits: after the integrated circuit front-end thin film deposition process is completed, the TiN diffusion barrier layer is directly deposited. The working pressure is 0.1-2 Pa, the nitrogen partial pressure is 0.016 Pa-0.25 Pa, the other gas is argon, the Ti target sputtering power density is 2-7 W/cm ² , and the bias voltage alternating parameters are between -50 V and -125V; the alternating period is 1 minute, and the thickness of TiN coating deposition is about 100 nm.

Example 2

A preparation method for a dense artificial joint surface strengthening layer TiN: first, the surface to be treated of the artificial joint is cleaned, and the cleaning treatment includes degreasing, oil removal, ash removal, insulation layer removal and vacuum vapor deposition. Clean the surface by sputtering. Place it in a vacuum chamber; inject Ar gas at 0.1-10Pa, make the mechanical parts to be processed in a negative bias state of 0-1000V, the negative bias triggers plasma generation, and the ion bombards the surface to be treated to further clean the surface for 5-20 The anti-sputtering method cleaning is completed in minutes; the Ti or Cr intermediate layer is deposited on the treated surface through the magnetron sputtering source, the target sputtering power density is 2-7 W/cm ² , and the thickness of the intermediate layer is 50 nm-200 nm; The TiN coating is then deposited by sputtering, the nitrogen partial pressure is 0.1 Pa, the sputtering power density can be 2, 5, 7 W/cm ² , and the values of the alternating bias parameters are -75V and -150V; alternating The cycle is 2 minutes or 5 minutes, and the thickness is 3, 5, 7, 9 microns.

Example 3

A preparation method for the reinforcement layer CrN of a dense injection mold: firstly, a primary cleaning treatment is performed on the surface of the mold to be treated, and the cleaning treatment includes degreasing, oil removal, dust removal, and insulation layer removal. Further cleaning: place it in a vacuum chamber; inject Ar gas at 0.1-10Pa, make the mechanical parts to be processed in a negative bias state of 0-1000V, the negative bias triggers plasma generation, and the ion bombards the surface to be treated for further cleaning Surface 5-20 minutes. Deposit a Ti or Cr intermediate layer on the treated surface through a magnetron sputtering source, the target sputtering power density is 2-7 W/cm ² , and the thickness of the intermediate layer is 50 nm-200 nm; then deposit a CrN coating by sputtering , the partial pressure of nitrogen is 0.2 Pa, the sputtering power density can be 2, 5, 7 W/cm ² , the values of alternating bias voltage parameters are -80V and -150V; the alternating period is 1 minute or 3 minutes, and the thickness is 3, 5, 7, 9 microns.

The hardness of the CrN coating is (1700Hv-2600Hv), lower stress (0.1 GPa -1GPa), the preferred orientation has two directions of [111] and [100], the corresponding grain ratio is 0-0.5, and the grain size About 10nm-200nm.

Claims (3)

1. a preparation method for fine and close nitride ceramics coating, first cleans the pending surface of mechanical component; Pass through again reactive deposition legal system for nitride coatings, it is characterized in that, in the process of reactive deposition legal system for nitride coatings, be biased between high bias voltage and low bias voltage and alternately change; Described high bias voltage is arbitrary in 0--80V, and low bias voltage is arbitrary in-80 V--150V; The reaction times of each bias voltage is 1 minute-10 minutes.

2. the preparation method of fine and close nitride ceramics coating as claimed in claim 1, is characterized in that, preparing the Ti that first adopts vapour deposition process to deposit 50 nm-200 nm thickness before nitride coatings or Cr middle layer in surface.

3. the fine and close nitride ceramics coating that the preparation method of the fine and close nitride ceramics coating based on described in claim 1 or 2 obtains, it is characterized in that, the hardness of described nitride ceramics coating is 1700Hv-2600Hv, stress is 0.1GPa-1GPa, preferred orientation is made up of [111] and [100] two kinds of directions, crystal grain ratio is 0-0.5, and grain-size is at 10 nm-200nm.