CN108624863B

CN108624863B - Surface hardness enhancement coating and preparation method thereof

Info

Publication number: CN108624863B
Application number: CN201810292702.XA
Authority: CN
Inventors: 周海涛; 罗炳威; 刘大博; 罗飞; 田野; 陈冬生
Original assignee: AECC Beijing Institute of Aeronautical Materials
Current assignee: AECC Beijing Institute of Aeronautical Materials
Priority date: 2018-03-30
Filing date: 2018-03-30
Publication date: 2020-12-29
Anticipated expiration: 2038-03-30
Also published as: CN108624863A

Abstract

The invention relates to a surface hardness enhanced coating and a preparation method thereof, wherein the enhanced coating is composed of a titanium carbide layer and a graphite layer, and the preparation method comprises the following steps: (1) ultrasonically cleaning and airing metal titanium or titanium alloy by using alcohol and acetone; (2) placing metal titanium or titanium alloy in a plasma enhanced chemical vapor deposition device, and pumping to a vacuum degree lower than 1x10 by using a mechanical pump^‑ ¹Pa; (3) argon gas of 200 sccm-400 sccm is introduced, and the temperature is raised to 500-900 ℃ at the speed of 3-10 ℃/min; (4) introducing 10-50 sccm methane gas, closing argon, opening a radio frequency source, setting the radio frequency power to be 100-300W, and growing for 0.5-2 h; (5) and closing the radio frequency source, introducing argon gas of 200-400 sccm, stopping introducing the methane gas, and naturally cooling to room temperature to obtain the titanium carbide/graphite reinforced coating. According to the invention, the ratio of titanium carbide and graphite is conveniently adjusted by controlling parameters such as methane gas flow, growth time and the like, so that the performance of the coating is modulated.

Description

Surface hardness enhancement coating and preparation method thereof

Technical Field

The invention belongs to the technical field of surface treatment.

Background

Titanium carbide (TiC) has the advantages of high melting point (3050 ℃), high Vickers hardness (30 GPa), high wear resistance, excellent high-temperature oxidation resistance and the like, and is widely applied to the fields of cutting tools, dies and aviation materials. However, titanium carbide coatings are brittle and easily collapse during use, and two main proposals are currently made to overcome this disadvantage. The scheme is that a titanium carbonitride (TiCN) coating is used for replacing a titanium carbide coating, and nitrogen atom doping can obviously improve the toughness and wear resistance of the coating, so that the heat resistance and corrosion resistance of a workpiece are improved; the second scheme is to prepare the titanium carbide and graphite composite coating, and the composite coating can reduce the friction factor under high contact stress and reduce mass abrasion, thereby improving the abrasion resistance. In patent CN201610707678.2, the inventor immerses a titanium carbide electrode in a processing liquid composed of alkyl modified graphite and kerosene, melts the titanium carbide by energy generated by pulse discharge, and co-deposits the titanium carbide and graphite on the surface of a workpiece to form a titanium carbide/graphite composite coating.

Disclosure of Invention

The invention aims to

In view of the above, the present invention provides a simple and easy method for preparing a titanium carbide/graphite composite coating.

The technical scheme of the invention is that

A surface hardness enhancement coating, the enhancement coating is composed of a titanium carbide layer and a graphite layer. The enhancement coating is deposited on the surface of the metallic titanium or titanium alloy. The titanium carbide layer is in contact with the surface of the metallic titanium or titanium alloy, and the graphite layer is positioned on the titanium carbide layer. The thickness of the titanium carbide layer is 3-5 μm, and the thickness of the graphite layer is 100-300 nm.

A method of preparing a surface hardness enhancement coating, comprising the steps of:

(1) carrying out ultrasonic cleaning on metal titanium or titanium alloy and airing;

(2) placing metal titanium or titanium alloy in plasma enhanced chemical vapor deposition equipment, and vacuumizing the plasma enhanced chemical vapor deposition equipment;

(3) introducing argon gas of 200 sccm-400 sccm, and heating the plasma enhanced chemical vapor deposition equipment to 500-900 ℃ at the rate of 3-10 ℃/min;

(4) introducing 10-50 sccm methane gas, closing argon, opening a radio frequency source, setting the radio frequency power to be 100-300W, and growing for 0.5-2 h;

(5) and closing the radio frequency source, introducing argon gas of 200-400 sccm, stopping introducing the methane gas, and cooling the plasma enhanced chemical vapor deposition equipment to room temperature to obtain the titanium carbide/graphite enhanced coating.

Preferably, step (1) uses alcohol and acetone to carry out ultrasonic cleaning and air drying on the metal titanium or titanium alloy.

Preferably, the vacuum degree of the step (2) plasma enhanced chemical vapor deposition device is less than 1x10^-1Pa。

Compared with the prior art, the invention has the following beneficial effects:

1. the process is simple. In the invention, after titanium is introduced into the plasma enhanced chemical vapor deposition equipment, the growth of titanium carbide and graphite is carried out simultaneously, and a plurality of steps of firstly preparing a titanium carbide raw material and a graphite raw material respectively, then carrying out surface modification and codeposition and the like in the prior art are omitted.

2. The impurity pollution is less. In the invention, titanium carbide and graphite grow in a vacuum furnace, but in the prior art, graphite needs to be dissolved in organic solution, and the organic solution can pollute the titanium carbide/graphite composite coating and reduce the performance of the coating.

3. The titanium carbide/graphite ratio can be conveniently adjusted. According to the invention, the ratio of titanium carbide and graphite is conveniently adjusted by controlling parameters such as methane gas flow, growth time and the like, so that the performance of the coating is modulated.

Drawings

FIG. 1 is an X-ray diffraction curve (curve 2) of a titanium carbide/graphite composite coating prepared in example 1 of the present invention, and curve 1 is an X-ray diffraction curve of an as-grown composite coating sample.

Fig. 2 is a raman spectrum curve of the titanium carbide/graphite composite coating prepared in example 1 of the present invention.

Fig. 3 is a scanning electron micrograph of the titanium carbide/graphite composite coating prepared in example 1 of the present invention.

Detailed Description

The present invention is further illustrated below with reference to specific examples, which are intended to be illustrative only and not to limit the scope of the invention.

Example 1

1. Ultrasonically cleaning the metal titanium for 3 times by using alcohol and acetone, and naturally drying;

2. introducing titanium metal into a plasma enhanced chemical vapor deposition device, and pumping to a vacuum degree lower than 1x10 by using a mechanical pump^-1Pa；

3. Introducing argon of 400sccm, and heating to 900 ℃ at the speed of 10 ℃/min;

4. introducing 30sccm methane gas, closing argon, opening a radio frequency source, setting the radio frequency power to be 300W, and growing for 0.5 h;

5. and (3) closing the radio frequency source, introducing argon gas of 400sccm, stopping introducing the methane gas, and naturally cooling to room temperature to obtain the titanium carbide/graphite reinforced coating.

In FIG. 1, curve 2 is the XRD diffraction curve of the composite coating, the characteristic peak of TiC is marked in the curve, and curve 1 is the X-ray diffraction curve of a comparison sample part without the composite coating; FIG. 2 is a Raman spectrum curve of the composite coating, with characteristic peaks of graphite marked; FIG. 3 is a scanning electron micrograph of the composite coating, the titanium carbide layer having a thickness of 5 μm and the graphite layer having a thickness of 300 nm. The hardness of the sample piece without the grown coating was measured to be 718 under a load of 10g, and the hardness of the sample piece without the grown coating was 204, and it was found that the hardness of the surface of the workpiece was increased by 2.5 times due to the presence of the titanium carbide/graphite composite coating.

Example 2

2. introducing titanium alloy into plasma enhanced chemical vapor deposition equipment, and pumping to a vacuum degree lower than 1x10 by using a mechanical pump^-1Pa；

3. Introducing 200sccm argon, and heating to 500 ℃ at the speed of 3 ℃/min;

4. introducing 10sccm methane gas, closing argon, opening a radio frequency source, setting the radio frequency power to be 100W, and growing for 2 h;

5. and (3) closing the radio frequency source, introducing 200sccm argon, stopping introducing the methane gas, and naturally cooling to room temperature to obtain the titanium carbide/graphite reinforced coating.

The titanium carbide layer is 3 μm thick, and the graphite layer is 100nm thick. The hardness was 605 and the hardness of the sample piece without the grown coating was 204 when measured under a load of 10g, and it was found that the hardness of the surface of the workpiece was increased by 2 times due to the presence of the titanium carbide/graphite composite coating.

Example 3

3. Introducing argon of 400sccm, and heating to 700 ℃ at the speed of 5 ℃/min;

4. introducing 40sccm methane gas, closing argon, opening a radio frequency source, setting the radio frequency power to be 200W, and growing for 1.5 h;

The titanium carbide layer is 4 μm thick, and the graphite layer is 200nm thick. The hardness was 653 measured under a load of 10g, and the hardness of the sample part without the grown coating was 204, which shows that the hardness of the surface of the workpiece was increased by 2.2 times due to the presence of the titanium carbide/graphite composite coating.

Claims

1. A surface hardness enhancement coating, characterized in that the enhancement coating is formed by the simultaneous growth of a titanium carbide layer and a graphite layer; the reinforced coating is deposited on the surface of the metallic titanium or the titanium alloy; the titanium carbide layer is in contact with the surface of the metal titanium or the titanium alloy, and the graphite layer is positioned above the titanium carbide layer; the thickness of the titanium carbide layer is 3-5 μm, and the thickness of the graphite layer is 100-300 nm.

2. A method of preparing a surface hardness enhancing coating according to claim 1, comprising the steps of:

(1) carrying out ultrasonic cleaning on metal titanium or titanium alloy;

3. The method according to claim 2, wherein the metallic titanium or titanium alloy is ultrasonically cleaned and dried by using alcohol and acetone in the step (1).

4. The production method according to claim 2, wherein the degree of vacuum of the plasma enhanced chemical vapor deposition apparatus of the step (2) is less than 1x10^-1Pa。