Search

CN-118007061-B - Method for simultaneously improving mechanical property and thickness of ta-C coating

CN118007061BCN 118007061 BCN118007061 BCN 118007061BCN-118007061-B

Abstract

The invention belongs to the technical field of substrate surface modification, and discloses a method for simultaneously improving the mechanical property and thickness of a ta-C coating, which comprises the specific steps that the coating is structurally a (metal layer/ta-C layer) n multi-layer coating, wherein n is 2-6, the thickness ratio of the metal layer to the ta-C layer is 1:2-4, the thickness of the ta-C layer is 180-220nm, the ta-C layer is deposited for multiple times by adopting a PVD method in stages, and vacuum in-situ cooling is carried out after each deposition. According to the invention, the stress is released by depositing the multilayer coating and utilizing the intermediate metal layer, so that the overall thickness of the coating is improved, and meanwhile, the ta-C internal stress is released by selecting an appropriate metal layer, an appropriate cycle period and the thickness ratio of the metal layer to the multi-stage ta-C layer, so that the overall thickness of the coating is improved, the service life of a workpiece is prolonged, and the method is further suitable for different application environments.

Inventors

  • WANG JINBIN
  • XIE ZHIJUN
  • SONG HONGJIA
  • ZHONG XIANGLI
  • LI JIALIN
  • GONG LING

Assignees

  • 湘潭大学

Dates

Publication Date
20260512
Application Date
20240202

Claims (7)

  1. 1. A method for simultaneously improving the mechanical property and thickness of a ta-C coating is characterized in that the coating has a structure of a multi-layer coating consisting of a metal layer and a ta-C layer which are alternately circulated for n times; wherein n is 2-6, and the thickness ratio of the metal layer to the ta-C layer is 1:2-4; The ta-C layer is deposited for a plurality of times by adopting a physical vapor deposition method in a staged way, vacuum in-situ cooling is carried out after each deposition in the deposition process, and the deposition times are 2-4 times.
  2. 2. A method for simultaneously improving the mechanical properties and the thickness of a ta-C coating according to claim 1, characterized in that the thickness of the ta-C layer is 180-220nm.
  3. 3. The method for simultaneously improving the mechanical properties and the thickness of a ta-C coating according to claim 1, wherein the metal layer is prepared by a physical vapor deposition method.
  4. 4. A method for simultaneously improving the mechanical properties and thickness of ta-C coatings according to claim 3, characterized in that said physical vapor deposition method is an arc ion plating technique.
  5. 5. The method for simultaneously improving the mechanical properties and the thickness of a ta-C coating according to claim 1, wherein the metal layer is any one of Ti, cr, tiAl and CrAl.
  6. 6. Method for simultaneously improving the mechanical properties and the thickness of a ta-C coating according to any of the claims 1-5, characterized in that the coating preparation method comprises in particular the following steps: (1) Carrying out Ar + bombardment etching on the cleaned substrate in a vacuum environment to remove impurities on the surface of the substrate for later use; (2) A, depositing a metal layer, namely introducing Ar gas, starting a pure metal target, and depositing the metal layer on the substrate by adopting an arc ion plating technology; (3) Depositing a ta-C coating, namely depositing the ta-C coating on the substrate prepared in the step (2) by adopting an arc ion plating technology; (4) Cooling, namely cooling the substrate obtained in the step (3) in situ under vacuum until the temperature of the coating is reduced to below 80 ℃; (5) Repeating the steps (3) and (4) to obtain a multi-stage ta-C coating; (6) And (3) repeating the steps (2) - (5) after the ta-C coating is prepared in the step (5), so as to obtain the (metal layer/ta-C layer) n multilayer coating.
  7. 7. The method for simultaneously improving the mechanical properties and the thickness of the ta-C coating according to claim 6, wherein the step of cleaning in the step (1) is that the substrate is ultrasonically cleaned for 15-20min by using ultrapure water, acetone and alcohol and dried by nitrogen; the etching process parameters are that Ar gas flow is 20-40sccm, negative bias is 100-110V, and etching time is 2100s; the technological parameters of the metal layer deposition in the step (2) are that Ar gas flow is 10-40sccm, negative bias is 40-60V, arc current is 60-80A, the target material is a pure metal target, and deposition time is 600s; the technological parameters of the ta-C coating deposition in the step (3) are that Ar gas flow is 10-20sccm, negative bias is 100-110V, target current is 40-50A, and deposition time is 600s.

Description

Method for simultaneously improving mechanical property and thickness of ta-C coating Technical Field The invention belongs to the technical field of substrate surface modification, and particularly relates to a method for simultaneously improving the mechanical property and thickness of a ta-C coating. Background The tetrahedral amorphous carbon (ta-C) film belongs to one of the hydrogen-free diamond-like carbon (DLC) films, has high hardness, good chemical stability, low friction coefficient and excellent wear resistance, and is widely used as a wear-resistant coating on the surfaces of tools, dies, precision engineering parts and the like. As the wear-resistant coating, its service life is closely related to its mechanical properties, and its thickness is an important factor affecting its life, however, excellent mechanical properties and high thickness are a pair of contradictors. Because the mechanical properties such as the hardness of the ta-C coating are related to the sp 3 bond content, the higher the sp 3 bond content is, the more excellent the mechanical properties such as the hardness are, but the higher the sp 3 hybridization bond can cause the average coordination number of carbon atoms in the film to be relatively higher, so that the three-dimensional network structure of the ta-C coating is excessively restrained, larger internal stress is generated, and when the thickness of the coating exceeds a certain value, the ta-C coating can generate cracks, wrinkles and even fall off. For this reason, how to provide a method for simultaneously improving the mechanical properties and thickness of ta-C coatings is a problem to be solved by the skilled person for long life wear resistant applications. Disclosure of Invention In order to solve the technical problems, the invention provides a method for simultaneously improving the mechanical property and the thickness of the ta-C coating. In order to achieve the above purpose, the present invention adopts the following technical scheme: a method for improving the mechanical property and thickness of a ta-C coating simultaneously, wherein the coating has a structure of n layers of (metal layer/ta-C layer); wherein n is 2-6, and the thickness ratio of the metal layer to the ta-C layer is 1:2-4. If the cycle period is too small, the overall thickness of the coating is low, and if the cycle period is too large, the coating can fall off; If the metal layer is too thick, the overall hardness of the coating is reduced, and if the ta-C layer is too thick, the coating is dropped off due to too large internal stress, so that the thickness ratio of the metal layer to the ta-C layer should be proper. Preferably, the thickness of the ta-C layer is 180-220nm. Preferably, the metal layer and the ta-C layer are prepared by physical vapor deposition. Preferably, the ta-C layer is deposited in stages by physical vapor deposition. The multi-stage ta-C coating is obtained through vacuum in-situ cooling, the deposition temperature of the ta-C coating is reduced, the sp 3 bond content is improved, and therefore the mechanical properties such as hardness, abrasion resistance and the like are improved. Preferably, the number of depositions is 2-4. Preferably, vacuum in-situ cooling is performed after each deposition in the deposition process. According to the invention, the ta-C coating is deposited for multiple times by adopting a PVD method, vacuum in-situ cooling is carried out after each deposition, the deposition temperature of the ta-C coating is lower than 80 ℃ by a cooling process, and graphitization transformation of the coating is prevented, so that the sp 3 bond content of the coating is improved, and further the mechanical properties such as hardness, wear resistance and the like are improved, meanwhile, the vacuum in-situ cooling does not increase the movement of samples in the process, expose the atmosphere environment and the like, and the process cost is low, the operation is easy, and the reliability is high. Preferably, the specific step of cooling is to close the gas channel and perform vacuum in-situ cooling under 7X 10 -3 Pa vacuum degree until the coating temperature is reduced to below 80 ℃. Preferably, the physical vapor deposition method is an arc ion plating technique. The arc ion plating technology adopted by the invention has the advantages of good ion diffraction, good uniformity of a deposited film layer and the like, has high controllability of technological parameters, and can realize the preparation of the coating with high density, high binding force and excellent comprehensive mechanical properties. Preferably, the metal layer is any one of Ti, cr, tiAl and CrAl. Preferably, the coating preparation method specifically comprises the following specific steps: (1) Carrying out Ar+ bombardment etching on the cleaned substrate in a vacuum environment to remove impurities on the surface of the substrate for later use; (2) A, depositing a metal laye