Method for preparing titanium alloy coating through cold spraying

Abstract

The invention relates to a method for preparing a titanium alloy coating through cold spraying. Belongs to the technical field of cold spraying. The method comprises the following steps: firstly, preparing nanoscale TC4 powder, wherein the average particle size is 20 microns; cleaning and sand blasting roughening are sequentially carried out on the surface of the TC4 substrate under the technological conditions that the air pressure intensity is 0.4 MPa, the sand blasting distance is 10 cm, and the moving speed is 70 cm / min. And spraying and depositing the prepared mixed powder on the surface of TC4 under a certain condition by using a Laval spray gun by adopting cold gas power spraying equipment to form a coating. The cold spraying conditions are that helium is used as working gas, the powder feeding amount is 20 g / min, the moving speed of a spray gun is 1 cm / s, the spraying pressure intensity is 0.3-0.9 MPa, the spraying distance is 2 cm, and the gas temperature is 400-600 DEG C. The TC4 coating is successfully prepared through the cold spraying technology, the TC4 coating is tightly combined with a TC4 base body, and the method can be used for repairing a TC4 titanium alloy workpiece.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of spraying, in particular to a method for preparing a titanium alloy coating by cold spraying. BACKGROUND

[0002] TC4 alloy, as the first practical titanium alloy, has been developed since 1954, and has become the ace alloy in the titanium alloy industry due to its good heat resistance, strength, plasticity, toughness, formability, weldability, corrosion resistance and biocompatibility. However, due to the low wear resistance of titanium alloy, surface scratches are prone to occur during service, and the low processing temperature of the cold spraying process is very suitable for surface repair of temperature-sensitive titanium alloy parts.

[0003] Cold spraying is a surface spraying process that uses compressed gas to accelerate the sprayed particles to exceed the critical speed, and the sprayed particles plastically deform upon impact on the substrate surface to form a dense material layer. Compared with thermal spraying technology, cold spraying can greatly avoid problems such as oxidation, phase change and grain growth of metal particles. The cold spraying process has little effect on the structure of the sprayed material, and can achieve deposition at low temperature. Moreover, cold spraying can deposit thick coatings with high deposition efficiency, and can be used for repairing the surface of parts, enhancing the wear resistance of the surface of parts and additive manufacturing, and is commonly used in the fields of aerospace, automobiles, oceans, etc., to protect the substrate from low-temperature corrosion, oxidation or other harsh working environments. SUMMARY

[0004] The purpose of the present application is to provide a method for preparing a titanium alloy coating by cold spraying, which has a simple preparation process and a complete and dense coating.

[0005] The technical solution adopted by the present application is: a method for preparing a titanium alloy coating by cold spraying, characterized by comprising the following steps: (1) preparing TC4 powder; (2) sequentially cleaning and sandblasting the surface of the TC4 substrate; (3) loading the prepared spraying powder into the powder feeder of the cold spraying equipment, using a cold gas dynamic spraying equipment to spray and deposit the prepared powder onto the surface of the TC4 substrate to form a coating.

[0006] The method for preparing a titanium alloy coating by cold spraying, in step (1), the TC4 powder has a spherical or spherical-like morphology, and the average particle size is 20 μm.

[0007] The cold spraying method for preparing the titanium alloy coating, in step (2), the TC4 substrate is subjected to sand blasting treatment before spraying. The TC4 titanium alloy substrate is subjected to roughening treatment by using 40# quartz sand. The sand blasting process conditions are as follows: the air pressure is 0.4 MPa, the sand blasting distance is 10 cm, and the moving speed is 70 cm / min.

[0008] The cold spraying method for preparing the titanium alloy coating, in step (3), the cold spraying process conditions are as follows: the working gas used is helium, the gas temperature is 400-600 DEG C, the spraying pressure is 0.3-0.9 MPa, the spraying distance is 2 cm, the moving speed of the spray gun is 1 cm / s, and the powder feeding amount is 20 g / min.

[0009] The cold spraying method for preparing the titanium alloy coating, in step (3), the spray gun is smooth and unblocked for a long time.

[0010] The metal substrate is a TC4 titanium alloy substrate.

[0011] The advantages and beneficial effects of the present application are as follows:

[0012] The present application repairs the surface pits of the TC4 titanium alloy thin plate by cold spraying TC4 titanium alloy powder on the TC4 titanium alloy substrate. The cold spraying technology is used for preparation, and there is no oxidation and phase change phenomenon, the treatment process is simple, and the performance of the substrate is avoided. The present application has simple and reasonable preparation process, and the cold spraying technology used has small thermal influence on the TC4 titanium alloy material, and a complete and dense TC4 titanium alloy coating can be obtained. DETAILED DESCRIPTION

[0013] In the specific implementation process, the cold spraying method for preparing the titanium alloy coating of the present application first prepares spherical or spherical TC4 titanium alloy powder; then the cold spraying equipment is used, the prepared TC4 titanium alloy powder is sprayed and deposited on the surface of the TC4 substrate under certain conditions by using a Laval spray gun, and a coating is formed.

[0014] The process parameters of the method are as follows: helium is used as the working gas, the powder feeding amount is 20 g / min, the moving speed of the spray gun is 1 cm / s, the spraying pressure is 0.3-0.9 MPa, the spraying distance is 2 cm, and the gas temperature is 400-600 DEG C.

[0015] The present application will be further described below in combination with specific embodiments.

[0016] Example 1

[0017] In this embodiment, TC4 titanium alloy powder with an average particle size of 20 μm is sprayed onto a TC4 titanium alloy substrate that has been cleaned and sandblasted by a Laval spray gun. The sandblasting process conditions are: air pressure of 0.4 MPa, sandblasting distance of 10 cm, and moving speed of 70 cm / min. The specific parameters of cold spraying are: working gas is helium, powder feeding amount is 20 g / min, spraying pressure is 0.3 MPa, temperature is 500 °C, spraying distance is 2 cm, spray gun moving speed is 1 cm / s, and spraying angle is 90°. The porosity of the TC4 titanium alloy coating prepared in this embodiment is 4.26%.

[0018] Example 2

[0019] In this embodiment, TC4 titanium alloy powder with an average particle size of 20 μm is sprayed onto a TC4 titanium alloy substrate that has been cleaned and sandblasted by a Laval spray gun. The sandblasting process conditions are: air pressure of 0.4 MPa, sandblasting distance of 10 cm, and moving speed of 70 cm / min. The specific parameters of cold spraying are: working gas is helium, powder feeding amount is 20 g / min, spraying pressure is 0.6 MPa, temperature is 500 °C, spraying distance is 2 cm, spray gun moving speed is 1 cm / s, and spraying angle is 90°. The porosity of the TC4 titanium alloy coating prepared in this embodiment is 2.87%.

[0020] Example 3

[0021] In this embodiment, TC4 titanium alloy powder with an average particle size of 20 μm is sprayed onto a TC4 titanium alloy substrate that has been cleaned and sandblasted by a Laval spray gun. The sandblasting process conditions are: air pressure of 0.4 MPa, sandblasting distance of 10 cm, and moving speed of 70 cm / min. The specific parameters of cold spraying are: working gas is helium, powder feeding amount is 20 g / min, spraying pressure is 0.9 MPa, temperature is 500 °C, spraying distance is 2 cm, spray gun moving speed is 1 cm / s, and spraying angle is 90°. The porosity of the TC4 titanium alloy coating prepared in this embodiment is 0.68%.

[0022] Example 4

[0023] In this embodiment, TC4 titanium alloy powder with an average particle size of 20 μm is sprayed onto a TC4 titanium alloy substrate that has been cleaned and sandblasted by a Laval spray gun. The sandblasting process conditions are: air pressure of 0.4 MPa, sandblasting distance of 10 cm, and moving speed of 70 cm / min. The specific parameters of cold spraying are: working gas is helium, powder feeding amount is 20 g / min, spraying pressure is 0.9 MPa, temperature is 400 °C, spraying distance is 2 cm, spray gun moving speed is 1 cm / s, and spraying angle is 90°. The porosity of the TC4 titanium alloy coating prepared in this embodiment is 8.9%.

[0024] Example 5

[0025] In this example, TC4 titanium alloy powder with an average particle size of 20 μm was sprayed onto a TC4 titanium alloy substrate that had been cleaned and grit blasted by a Laval spray gun. The blasting process conditions were: air pressure of 0.4 MPa, blasting distance of 10 cm, and moving speed of 70 cm / min. The specific parameters of the cold spraying were: working gas of helium, powder feeding amount of 20 g / min, spraying pressure of 0.9 MPa, temperature of 600 °C, spraying distance of 2 cm, spray gun moving speed of 1 cm / s, and spraying angle of 90°. The porosity of the TC4 titanium alloy coating prepared in this example was 0.8%.

Claims

1. A method of cold spray preparation of a titanium alloy coating, characterized in that The method comprises the following steps: (1) preparing TC4 powder (2) sequentially performing cleaning and sand blasting roughening treatment on the surface of the TC4 base body (3) loading the prepared spraying powder into a powder feeder of a cold spraying device, and using the cold gas dynamic spraying device to spray and deposit the prepared powder on the surface of the TC4 base body to form a coating.

2. The method of cold-spray fabrication of a titanium alloy coating according to claim 1, characterized in that, In step (1), the TC4 powder has a spherical or spherical-like shape, and the average particle size is 20 microns.

3. The method of cold-spraying a titanium alloy coating according to claim 1, wherein In step (2), the TC4 base body is subjected to sand blasting treatment before spraying, and the TC4 titanium alloy base plate is subjected to roughening treatment using 40# quartz sand. The sand blasting process conditions are: air pressure of 0.4 MPa, sand blasting distance of 10 cm, and moving speed of 70 cm / min.

4. The method of cold-spraying a titanium alloy coating according to claim 1, wherein, In step (3), cold spraying refers to using a cold spraying device to deposit the prepared spraying powder on the base material through the high-speed airflow of a spray gun to obtain a titanium alloy coating. The specific cold spraying process parameters are: working gas is helium, temperature is 400-600 DEG C, spraying pressure is 0.3-0.9 MPa, spraying distance is 2 cm, spray gun moving speed is 1 cm / s, and powder feeding amount is 20 g / min.

5. The method of cold-spraying a titanium alloy coating according to claim 1, wherein, In step (3), the spray gun smoothly discharges powder for a long time and is not blocked.

6. The method of cold-spraying a titanium alloy coating according to claim 1, wherein, In step (3), during the cold spraying process, the temperature of the base body is less than 150 DEG C.