CN110735107A

CN110735107A - Ion surface etching method before preparation of diamond-like coating

Info

Publication number: CN110735107A
Application number: CN201911051814.7A
Authority: CN
Inventors: 黄雷; 李超; 洪东波; 袁军堂; 汪振华
Original assignee: Nanjing Tech University
Current assignee: Nanjing Tech University
Priority date: 2019-10-31
Filing date: 2019-10-31
Publication date: 2020-01-31

Abstract

The invention belongs to the field of diamond-like coating, and particularly relates to an ion surface etching method before preparation of diamond-like coating, which comprises the steps of material polishing, vacuumizing and heating, substrate cleaning and surface etching treatment, wherein two high-purity twin titanium targets are selected as targets, a medium-frequency magnetron sputtering method is adopted, pulse negative bias is matched, high-energy titanium ions are bombarded on the surface of the substrate to generate an etching effect, and the effect of modifying the surface of the substrate is achieved³Nm and 1.93E-11mm³(iv)/Nm; the invention is used as the pretreatment of the preparation of the diamond-like coatingThe process can improve the bonding strength of the coating, is advanced, is easy to produce and has pushing value.

Description

Ion surface etching method before preparation of diamond-like coating

Technical Field

The invention belongs to the field of diamond-like carbon coatings, and particularly relates to an ion surface etching method before preparation of an diamond-like carbon coating.

Background

The DLC coating technology is a new technology developed in response to market demands in recent decades and is which is an important way for improving the comprehensive performance of materials and parts, and the DLC coating technology is adopted to carry out surface modification on the materials and the parts, so that the surface hardness, the wear resistance, the impact toughness and the bending strength can be effectively improved, and the service life of the parts is prolonged.

The addition of a transition layer between a diamond-like coating and a substrate is the method which is most widely applied at present, Neiyangyin and the like (Nieyangyin, Anvingnong, Luchun, and the like.) the influence of Ti doping and Ti stress relaxation layers on the adhesion of a diamond-like film [ J ]. functional materials, 2009,40(2):226-229.) is researched that Ti is used as the transition layer to prepare the diamond-like coating, the addition of a Ti transition layer with the thickness of 70nm during the preparation of the Ti-DLC coating can effectively relieve the internal stress of the coating, the film-substrate binding force of the Ti-DLC coating can reach about 27N, the Ti-DLC coating without the Ti transition layer only has limited improvement on the binding force of 14N single Ti transition layer to DlC, and the improvement effect is worse when no Ti element is doped in the coating, the improvement effect is worse, people (Tizhao, Li Liuhe, Jingkai, et al, etc. (TiN group, Li Liu combination, Ti, Ningk, NC and NC) gradient transition layers show the effect on the wear resistance of a hard alloy deposition type film-like, and the combination of TiC/DLC/NC and the gradient of TiC/NC and the like, and the preparation of a great friction resistance of TiC/NC and the multilayer coating, and the gradient of a great friction factor, which are found that the gradient of TiC/NC and the gradient of a great friction resistance of a great friction-NC/DLC composite coating, and a great friction factor is obviously interfered with the same.

The substrate material is subjected to surface treatment before the DLC coating is prepared, common ways are etching, sandblasting, nitriding, ion implantation and the like. The main function of the surface pretreatment is to improve the chemical activity of the substrate surface, thereby promoting the formation of chemical bonds between the substrate surface atoms and coating elements on the interface and increasing the bonding strength. The influence of nitriding treatment on the performance of a TiAlSiN coating on the surface of a Zr4 alloy is researched by Zhoujiu et al (Zhoujiu, Xiangfang, Fengshitong, et al.) [ J ] metal heat treatment, 2018(1):142-146.), and the influence of nitriding treatment on the preparation of the TiAlSiN coating on the surface of the zirconium alloy is found to improve the surface hardness of the zirconium alloy, reduce the hardness difference between the zirconium alloy and the TiAlSiN coating, reduce the internal stress of the coating and further improve the film-substrate binding force, and the nitriding treatment can possibly form a ZrN phase on a film-substrate interface, thereby being beneficial to improving the binding force. The nitriding treatment has a good effect on the coating containing nitrogen elements, but the effect of improving the binding force in the preparation of the diamond-like carbon coating is not obvious, and the nitriding treatment and the coating preparation are carried out on different devices, so that a sample is easily polluted when exposed in the air. The preparation and performance research of diamond-like carbon films on the surfaces of titanium alloy subjected to sand blasting pretreatment [ J ] Beijing biomedical engineering, 2017,36(4):354 + 360.) prepares DLC coatings after carrying out sand blasting treatment on titanium alloy substrates, selects Al2O3 sands with different particle sizes, tests show that the bonding force of the coatings without sand blasting is 11N, the highest bonding force of the coatings after the sand blasting treatment reaches 45N, and the bonding force has the tendency of increasing firstly and then decreasing along with the increase of the particle size. The influence of the micro-sand blasting treatment on the DLC coating on the surface of the hard alloy is researched by Hufang et al (Hufang, Mingjiang, Lingsheng, micro-sand blasting pretreatment on the structure and the performance of a diamond-like carbon film deposited on the hard alloy [ J ]. China surface engineering, 2009,24(6):47-52.), the bonding forces of the coating without sand blasting and the coating subjected to the sand blasting treatment are respectively 30N and 55.7N, and the bonding strength is highest when the surface roughness is controlled within the range of 0.3-0.4 mu m after the sand blasting. The surface of the hard alloy is coarsened by sand blasting treatment, so that the mechanical locking effect between film bases is enhanced, the frictional resistance between the substrate and the coating is increased, and the bonding force of the film bases is improved; the sand blasting treatment has the defects that the surface of a substrate is greatly damaged, the surface roughness is greatly increased, the friction coefficient of a rough surface is obviously increased, and the characteristics of low friction coefficient and good wear resistance of a DLC coating cannot be embodied.

In the existing transition layer technology, the performance of a single transition layer on a DLC coating is not improved enough to meet the application requirement, but the repeatability of the preparation of a composite transition layer is poor, the surface pretreatment technology can cause obvious damage to the surface of a substrate and reduce the friction performance of the DLC coating, surface pretreatment technologies also need additional equipment, the preparation process of the coating cannot be times of forming, and a large number of error factors can be introduced.

Disclosure of Invention

The invention aims to provide an ion surface etching method before preparation of diamond-like coating, which achieves the effect of removing materials by bombarding the surface of hard alloy with high-energy ions to form an etching effect.

The technical scheme for achieving the aim of the invention is that the ion surface etching method before the preparation of the diamond-like coating is adopted to perform etching treatment on the surface of YG8 hard alloy by adopting a medium-frequency magnetron sputtering method, and the target material of the medium-frequency magnetron sputtering is two high-purity twin titanium targets.

, replacing Ti with Cr, W and Zr.

, the method includes the steps of:

step (1): pretreating the YG8 hard alloy matrix;

step (2): placing the YG8 hard alloy matrix after pretreatment into a vacuum chamber;

and (3): plasma cleaning;

and (4): and starting a medium-frequency magnetron sputtering power supply, and performing ion etching treatment.

, the pretreatment of step (1) is specifically:

step (1-1): sequentially grinding the YG8 hard alloy base material by using coarse borax nitride paper and fine borax nitride paper until no scratch exists, and then polishing on polishing cloth until the surface roughness is 3-5 nm;

step (1-2): and sequentially placing the polished YG8 hard alloy into acetone, deionized water and absolute ethyl alcohol for ultrasonic cleaning for 10-20 min respectively.

, the step (2) is specifically that the YG8 hard alloy after being cleaned is placed into a vacuum chamber, vacuumized to be below 5E-3Pa, then the chamber is heated, and vacuumized to be below 5E-3 Pa.

, heating the cavity in the step (2) at a heating temperature of 100-120 ℃.

, specifically, the plasma cleaning in the step (3) is to introduce argon gas, the gas flow is 150-200 ml/min, the vacuum degree is set to be 1.2-1.6 Pa, the process of rotation is carried out, pulse bias voltage of-1200-1400V is applied to the substrate, the duty ratio is 30-60%, the substrate is kept for 10-20 min, and the plasma cleaning of the substrate is completed.

, specifically, the step (4) is to introduce argon, adjust the vacuum degree, turn on the medium frequency magnetron sputtering power supply, apply pulse bias voltage, perform etching treatment on the surface of YG8 hard alloy, wherein the rotation speed of the workpiece is 5-15 r/min, the revolution speed is 3-6 r/min.

, keeping the argon flow at 60-100 ml/min, vacuum degree at 1.2-1.4 Pa, intermediate frequency power supply current at 3.0-5.0A, frequency at 8KHz, pulse bias at-1000 to-1400V, duty ratio at 40-60%, and deposition time at 30-60 min.

Compared with the prior art, the invention has the remarkable advantages that:

(1) the surface etching treatment keeps the characteristics of the traditional titanium transition layer, titanium ions are left on the surface of the substrate and form bonds with carbon atoms in the DLC coating, the film-substrate binding force is improved, and the bombardment of the titanium ions can cause higher activity of particles on the surface of the substrate and strengthen the bonding effect on the film-substrate interface;

(2) the surface roughness of the substrate is increased in a nano scale by etching treatment, on the aspect of , the slightly increased surface roughness can increase the mechanical locking effect between film bases to obtain higher film base binding force than that of the traditional titanium transition layer, on the aspect of , the surface roughness is maintained within 30nm, the amplification is small, the friction coefficient is ensured not to be greatly increased, the low friction coefficient range of 0.10 to 0.20 can be controlled, and the nano-scale abrasive dust is filled in a depression to be beneficial to reducing the friction coefficient and the wear rate and improving the friction performance;

(3) compared with a gradient transition layer (such as Ti/TiC/TiCN and the like), the etching pretreatment structure of the surface of the substrate is simpler, the introduction of various working gases (such as methane, acetylene, nitrogen and the like) and complex structures is avoided, the repeatability of coating preparation is ensured, and the large fluctuation of the performance of the coating is avoided;

(4) the heating vacuum cavity plays an auxiliary role in the etching treatment process; the heating promotes the argon gas in the vacuum cavity to ionize to generate argon ions to bombard the target material, and can improve the energy of the titanium ions in the vacuum cavity and promote the process of bombarding the matrix by the titanium ions.

Drawings

FIG. 1 is a SEM image of the surface topography of example 1 after etching treatment;

FIG. 2 is a scratch pattern of the DLC coating of example 1;

FIG. 3 is an SEM image of the surface morphology of the Ti transition layer of comparative example 1.

Detailed Description

The present invention will be described in further detail with reference to the following examples and accompanying drawings.

Example 1:

titanium ion surface etching method, which comprises polishing YG8 hard alloy until the surface is bright and has no scratch, ultrasonically cleaning in acetone, deionized water and alcohol for 15min in sequence, placing the cleaned YG8 hard alloy into a vacuum chamber for vacuumizing, heating the chamber to 100 ℃, introducing Ar gas with a flow rate of 150ml/min and a vacuum degree of 1.6Pa after the vacuum degree of the chamber is 5E-3Pa, starting a bias power supply with a bias voltage of-1200V and a duty ratio of 60%, cleaning for 15min, introducing Ar gas with an Ar gas flow rate of 80ml/min and a vacuum degree of 1.2Pa after cleaning, starting an intermediate frequency power supply with a current of 4.0A, starting a pulse bias power supply with a bias voltage of-1000V and a duty ratio of 60%, and performing titanium ion etching treatment on the surface for 30 min.

Preparing a DLC coating on the surface of the transition layer, which specifically comprises the following steps: keeping the temperature of the cavity at 100 ℃, introducing Ar gas and acetylene, starting a medium-frequency power supply, wherein the flow of the Ar gas is 100ml/min, the flow of the acetylene is 20ml/min, and the vacuum degree of the cavity is set to be 1.4 Pa; and starting the intermediate frequency power supply, wherein the current is 5.0A, then starting the pulse bias power supply, the bias voltage is-1000V, the duty ratio is 30%, and preparing the DLC coating, wherein the deposition time is 40 min.

The test shows that the depth of titanium ion etching is 309nm, and the surface roughness is 16.16 nm; the surface roughness of the DLC coating is 14.82nm, the film-substrate binding force is 25.10N, the friction coefficient of the DLC coating to silicon nitride is 0.14, and the wear rate is 8.63E-13mm³Nm, friction coefficient with titanium alloy of 0.12, wear rate of 6.08E-13mm³/Nm。

Example 2:

titanium ion surface etching method, which comprises polishing YG8 hard alloy until the surface is bright and has no scratch, ultrasonically cleaning in acetone, deionized water and alcohol for 15min in sequence, placing the cleaned YG8 hard alloy into a vacuum chamber for vacuumizing, heating the chamber to 100 ℃, introducing Ar gas with a flow rate of 150ml/min and a vacuum degree of 1.6Pa after the vacuum degree of the chamber is 5E-3Pa, starting a bias power supply with a bias voltage of-1200V and a duty ratio of 60%, cleaning for 15min, introducing Ar gas with an Ar gas flow rate of 80ml/min and a vacuum degree of 1.2Pa after cleaning, starting an intermediate frequency power supply with a current of 4.0A, starting a pulse bias power supply with a bias voltage of-1100V and a duty ratio of 60%, and performing titanium ion etching treatment on the surface for 30 min.

The test shows that the depth of titanium ion etching is 356nm, and the surface roughness is 16.58 nm; the surface roughness of the DLC coating is 15.04nm, the film base binding force is 27.89N, the friction coefficient of the DLC coating to silicon nitride is 0.14, and the wear rate is 1.04E-12mm³/Nm, friction coefficient of the titanium alloy to the grinding is 0.14, and wear rate is 1.33E-12mm³/Nm。

Example 3:

titanium ion surface etching method, which comprises polishing YG8 hard alloy until the surface is bright and has no scratch, ultrasonically cleaning in acetone, deionized water and alcohol for 15min in sequence, placing the cleaned YG8 hard alloy into a vacuum chamber for vacuumizing, heating the chamber to 100 ℃, introducing Ar gas with a flow rate of 150ml/min and a vacuum degree of 1.6Pa after the vacuum degree of the chamber is 5E-3Pa, starting a bias power supply with a bias voltage of-1200V and a duty ratio of 60%, cleaning for 15min, introducing Ar gas with an Ar gas flow rate of 80ml/min and a vacuum degree of 1.2Pa after cleaning, starting an intermediate frequency power supply with a current of 4.0A, starting a pulse bias power supply with a bias voltage of-1200V and a duty ratio of 60%, and performing titanium ion etching treatment on the surface for 30 min.

The test shows that the depth of titanium ion etching is 407nm, and the surface roughness is 18.17 nm; the surface roughness of the DLC coating is 17.21nm, the film-substrate binding force is 30.23N, the friction coefficient of the DLC coating to silicon nitride is 0.15, and the wear rate is 1.18E-12mm³/Nm, friction coefficient with titanium alloy of 0.17, wear rate of 3.14E-12mm³/Nm。

Example 4:

titanium ion surface etching method, which comprises polishing YG8 hard alloy until the surface is bright and has no scratch, ultrasonically cleaning in acetone, deionized water and alcohol for 15min in sequence, placing the cleaned YG8 hard alloy into a vacuum chamber for vacuumizing, heating the chamber to 100 ℃, introducing Ar gas with a flow rate of 150ml/min and a vacuum degree of 1.6Pa after the vacuum degree of the chamber is 5E-3Pa, starting a bias power supply with a bias voltage of-1200V and a duty ratio of 60%, cleaning for 15min, introducing Ar gas with an Ar gas flow rate of 80ml/min and a vacuum degree of 1.2Pa after cleaning, starting an intermediate frequency power supply with a current of 4.0A, starting a pulse bias power supply with a bias voltage of-1000V and a duty ratio of 60%, and performing titanium ion etching treatment on the surface for 45 min.

The test shows that the depth of titanium ion etching is 420nm, and the surface roughness is 16.72 nm; the surface roughness of the DLC coating is 13.93nm, the film-substrate binding force is 25.72N, the friction coefficient of the DLC coating to silicon nitride is 0.15, and the wear rate is 9.85E-13mm³Nm, friction coefficient with titanium alloy of 0.13, wear rate of 8.14E-13mm³/Nm。

Example 5:

titanium ion surface etching method, which comprises polishing YG8 hard alloy until the surface is bright and has no scratch, ultrasonically cleaning in acetone, deionized water and alcohol for 15min in sequence, placing the cleaned YG8 hard alloy into a vacuum chamber for vacuumizing, heating the chamber to 100 ℃, introducing Ar gas with a flow rate of 150ml/min and a vacuum degree of 1.6Pa after the vacuum degree of the chamber is 5E-3Pa, starting a bias power supply with a bias voltage of-1200V and a duty ratio of 60%, cleaning for 15min, introducing Ar gas with an Ar gas flow rate of 80ml/min and a vacuum degree of 1.2Pa after cleaning, starting an intermediate frequency power supply with a current of 4.0A, starting a pulse bias power supply with a bias voltage of-1000V and a duty ratio of 60%, and performing titanium ion etching treatment on the surface for 60 min.

The test shows that the depth of titanium ion etching is 565nm, and the surface roughness is 17.28 nm; the surface roughness of the DLC coating is 15.49nm, the film-substrate binding force is 23.47N, the friction coefficient of the DLC coating to silicon nitride is 0.14, and the wear rate is 9.37E-13mm³Nm, friction coefficient with titanium alloy of 0.13, wear rate of 7.96E-13mm³/Nm。

Table 1 examples 1-5 partial process parameters and performance of the etching process

TABLE 2 mechanical Properties of examples 1-5 Diamond-like coatings

Comparative example 1:

method for preparing Ti transition layer by direct current magnetron sputtering, which comprises polishing YG8 hard alloy until the surface is bright and has no scratch, ultrasonically cleaning in acetone, deionized water and alcohol for 15min, placing cleaned YG8 hard alloy into a vacuum chamber, vacuumizing, heating the chamber to 100 deg.C, and keeping the vacuum degree of the chamber at 5E^-3And after Pa, introducing Ar gas with the flow rate of 150ml/min, setting the vacuum degree of the cavity to be 1.6Pa, starting a bias power supply, keeping the bias voltage at-1200V and the duty ratio at 60%, and cleaning for 15 min. After the cleaning is finished, introducing Ar gas and Ar gasThe flow rate is 150ml/min, and the vacuum degree of the cavity is set to be 1.4 Pa; and starting a direct current power supply, wherein the current is 6.0A, then starting a pulse bias power supply, the bias voltage is-500V, the duty ratio is 30%, depositing a Ti transition layer on the surface, and the coating time is 6 min.

The direct current Ti transition layer is tested to be 146nm thick and 2.80nm surface roughness. After the DLC coating is prepared, the film-substrate binding force is 17.39N, the surface roughness is 2.17nm, the friction coefficient of the DLC coating to silicon nitride is 0.09, and the wear rate is 8.09E-13mm³Nm, friction coefficient with titanium alloy of 0.10, wear rate of 1.18E-12mm³/Nm。

Comparative example 2:

method for preparing Ti transition layer by medium frequency magnetron sputtering, which comprises polishing YG8 hard alloy until the surface is bright and has no scratch, ultrasonically cleaning in acetone, deionized water and alcohol for 15min, placing the cleaned YG8 hard alloy into a vacuum chamber, vacuumizing, heating the chamber to 100 deg.C, and keeping the vacuum degree of the chamber at 5E^-3And after Pa, introducing Ar gas with the flow rate of 150ml/min, setting the vacuum degree of the cavity to be 1.6Pa, starting a bias power supply, keeping the bias voltage at-1200V and the duty ratio at 60%, and cleaning for 15 min. After cleaning, introducing Ar gas, wherein the flow of the Ar gas is 80ml/min, and the vacuum degree of the cavity is set to be 1.4 Pa; and starting the intermediate frequency power supply, wherein the current is 4.0A, then starting the pulse bias power supply, the bias voltage is-500V, the duty ratio is 30%, depositing a Ti transition layer on the surface, and the coating time is 30 min.

The test shows that the thickness of the intermediate frequency Ti transition layer is 215nm, and the surface roughness is 3.09 nm. After the DLC coating is prepared, the film-substrate binding force is 20.54N, the surface roughness is 3.46nm, the friction coefficient of the DLC coating to silicon nitride is 0.07, and the wear rate is 5.22E-13mm³Nm, friction coefficient of the titanium alloy to the grinding is 0.08, and wear rate is 1.00E-12mm³/Nm。

TABLE 3 comparison of Diamond-like coating Performance of etch treatment with two Ti transition layers

Claims

The ion surface etching method before the preparation of the -like diamond coating is characterized in that etching treatment is carried out on the surface of YG8 hard alloy by adopting a medium-frequency magnetron sputtering method, and the target material of the medium-frequency magnetron sputtering is two high-purity twin titanium targets.
2. The method of claim 1, wherein titanium is replaced with chromium, tungsten, or zirconium.
3. Method according to claim 1, characterized in that it comprises the following steps:

step (1): pretreating the YG8 hard alloy matrix;

step (2): placing the YG8 hard alloy matrix after pretreatment into a vacuum chamber;

and (3): plasma cleaning;

and (4): and starting a medium-frequency magnetron sputtering power supply, and performing ion etching treatment.
4. The method according to claim 3, wherein the pretreatment of step (1) is specifically:

step (1-1): sequentially grinding the YG8 hard alloy base material by using coarse borax nitride paper and fine borax nitride paper until no scratch exists, and then polishing on polishing cloth until the surface roughness is 3-5 nm;

step (1-2): and sequentially placing the polished YG8 hard alloy into acetone, deionized water and absolute ethyl alcohol for ultrasonic cleaning for 10-20 min respectively.
5. The method according to claim 4, wherein the step (2) is specifically: putting the cleaned YG8 hard alloy into a vacuum chamber, vacuumizing to below 5E-3Pa, heating the chamber, and vacuumizing to below 5E-3 Pa.
6. The method according to claim 5, wherein the heating temperature for heating the cavity in the step (2) is 100-120 ℃.
7. The method according to claim 3, wherein the step (3) of plasma cleaning is specifically as follows: argon is introduced, the gas flow is 150-200 ml/min, the vacuum degree is set to be 1.2-1.6 Pa, the substrate is opened and revolved, pulse bias voltage of-1200-1400V is applied to the substrate, the duty ratio is 30-60%, the substrate is kept for 10-20 min, and plasma cleaning of the substrate is completed.
8. The method according to claim 3, characterized in that said step (4) is in particular: introducing argon, adjusting the vacuum degree, starting a medium-frequency magnetron sputtering power supply, applying pulse bias voltage, carrying out etching treatment on the surface of the YG8 hard alloy, wherein the rotation speed of the workpiece is 5-15 r/min, and the revolution speed is 3-6 r/min.
9. The method of claim 8, wherein the argon flow is 60 to 100ml/min, the vacuum degree is maintained at 1.2 to 1.4Pa, the intermediate frequency power supply current is 3.0 to 5.0A, the frequency is 8KHz, the pulse bias voltage is-1000 to-1400V, the duty ratio is 40 to 60%, and the deposition time is 30 to 60 min.