阅读说明：本技术 一种冷喷涂制备硬质合金涂层的方法 (Method for preparing hard alloy coating by cold spraying ) 是由 邱瑜铭 邹芹 于 2019-11-01 设计创作，主要内容包括：本发明涉及一种冷喷涂制备硬质合金涂层的方法,属于冷喷涂的技术领域。本发明的冷喷涂制备硬质合金涂层的方法包括以下步骤：(1)在金属基体表面涂覆NiCrAlY底层；(2)在NiCrAlY底层上冷喷涂TiC和TiN<Sub>0.3</Sub>的混合粉末,制备Ti(C,N)硬质合金层。采用冷喷涂工艺成功制备了Ti(C,N)基硬质合金,硬质合金与基体的结合强度高,而且涂层组织致密,孔隙率低,可用于提高基体材料的耐磨、耐蚀以及耐高温性能。(The invention relates to a method for preparing a hard alloy coating by cold spraying, belonging to the technical field of cold spraying. The method for preparing the hard alloy coating by cold spraying comprises the following steps: (1) coating a NiCrAlY bottom layer on the surface of a metal substrate; (2) cold spraying TiC and TiN on NiCrAlY bottom layer 0.3 The Ti (C, N) hard alloy layer is prepared. The Ti (C, N) -based hard alloy is successfully prepared by adopting a cold spraying process, the bonding strength of the hard alloy and a matrix is high, and the coating structureCompact, low porosity, and can be used for improving the wear resistance, corrosion resistance and high temperature resistance of the matrix material.)

1. A method for preparing a hard alloy coating by cold spraying is characterized by comprising the following steps:

(1) coating a NiCrAlY bottom layer on the surface of a metal substrate;

(2) cold spraying TiC and TiN on NiCrAlY bottom layer_0.3The Ti (C, N) hard alloy layer is prepared.

2. The method for preparing a hard alloy coating by cold spraying according to claim 1, which comprises the step (3) of performing heat treatment at a temperature of 600 to 950 ℃ for 10 to 30 min.

3. The method for preparing a hard alloy coating by cold spraying according to claim 1, wherein the process conditions of the cold spraying are as follows: n2 is used as working gas, the gas temperature is 350-500 ℃, the gas pressure is 3.0-6.0 MPa, and the spraying distance is 25-50 mm.

4. The method of cold spray producing a cemented carbide coating according to claim 1, characterized in that: the metal matrix is an iron-based, nickel-based or titanium-based matrix.

5. The method of cold spray producing a cemented carbide coating according to claim 1, characterized in that: the NiCrAlY bottom layer is prepared by a spraying process, and the spraying process is arc spraying, flame spraying or plasma spraying.

6. The method of cold spray producing a cemented carbide coating according to claim 1, characterized in that: in the NiCrAlY bottom layer, the content of Cr is 12-30 at%, the content of Al is 5.0-12.0 at%, the content of Y is 0.5-1.5 at%, and the balance is Ni.

7. The method of cold spray producing a cemented carbide coating according to claim 1, characterized in that: the TiC and TiN_0.3The mixed powder of (2) is ball-milled and granulated.

8. The method of cold spray producing a cemented carbide coating according to claim 1, characterized in that: the TiC and TiN_0.3The mass ratio of (A) to (B) is 2: 8-3: 7.

9. A hard alloy coating characterized by being produced by the method according to any one of claims 1 to 8.

10. The cemented carbide coating of claim 9, characterized in that: the thickness of NiCrAlY bottom is 0.1-0.5 mm, and the thickness of coating is 0.1-1.0 mm.

Technical Field

The invention relates to the technical field of cold spraying, in particular to a method for preparing a hard alloy coating by cold spraying.

Background

The Ti (C, N) based hard alloy has better high temperature performance, wear resistance and chemical stability than the traditional hard alloy, and can save a great deal of strategic 'tungsten' and 'cobalt' resources, thus becoming a research hotspot of the hard alloy in recent years. The Ti (C, N) -based hard alloy has poor plastic deformation resistance and toughness, and Kieffer et al can improve the mechanical properties at room temperature and high temperature after adding TiN in a non-stoichiometric ratio into TiC, and more importantly, because a large number of N vacancy defects exist in TiNx in the non-stoichiometric ratio, the sintering temperature of the Ti (C, N) -based hard alloy is reduced, and the mechanical properties with excellent properties can be obtained at a not very high sintering temperature. However, the hot press sintering process limits the application of Ti (C, N) -based cemented carbides.

Cold Spray Coating (CGDS) is a technique in which compressed Gas is used as an accelerating medium to drive metal or alloy particles to impact a base material at a very high speed in a solid state, so that the particles are strongly plastically deformed to deposit and form a coating.

Disclosure of Invention

In order to solve the technical problems in the prior art, the invention aims to provide a method for preparing a hard alloy coating by cold spraying.

The method for preparing the hard alloy coating by cold spraying is characterized by comprising the following steps:

(1) coating a NiCrAlY bottom layer on the surface of a metal substrate;

(2) cold spraying TiC and TiN on NiCrAlY bottom layer_0.3The Ti (C, N) hard alloy layer is prepared.

Wherein, the method also comprises the step (3), the heat treatment is carried out at the temperature of 600-950 ℃, and the heat treatment time is 10-30 min.

Wherein the cold spraying process conditions are as follows: n2 is used as working gas, the gas temperature is 350-500 ℃, the gas pressure is 3.0-6.0 MPa, and the spraying distance is 25-50 mm.

Wherein the metal matrix is an iron-based, nickel-based or titanium-based matrix.

The NiCrAlY bottom layer is prepared through a spraying process, and the spraying process can be selected from electric arc spraying, flame spraying, plasma spraying and the like.

Wherein, in the NiCrAlY bottom layer, the content of Cr is 12-30 at%, the content of al is 5.0-12.0 at%, the content of Y is 0.5-1.5 at% of Y, and the balance is Ni.

Wherein, the TiC and TiN_0.3The mixed powder of (2) is ball-milled and granulated.

Wherein, the TiC and TiN_0.3The mass ratio of (A) to (B) is 2: 8-3: 7.

The second aspect of the invention also relates to a hard alloy coating prepared by the preparation method.

Wherein the thickness of the NiCrAlY bottom layer is 0.1-0.5 mm, and the thickness of the coating is 0.1-1.0 mm.

Compared with the prior art, the method for preparing the hard alloy coating by cold spraying has the following beneficial effects:

the Ti (C, N) -based hard alloy is successfully prepared by adopting a cold spraying process, the bonding strength of the hard alloy and a matrix is high, the coating structure is compact, the porosity is low, and the Ti (C, N) -based hard alloy can be used for improving the wear resistance, corrosion resistance and high temperature resistance of matrix materials.

Detailed Description

The method for preparing a hard alloy coating by cold spraying according to the present invention will be further described with reference to the following specific examples to help those skilled in the art to have a more complete, accurate and thorough understanding of the technical solution of the present invention.

TiN in the following examples_0.3The powder is prepared by the following method:

the raw materials are Ti powder (purity is more than 99.36%, granularity is less than 30 mu m) and CH₄N₂O (analytically pure). Ti powder and CH₄N₂O is mixed in a molar ratio of 6: 1. In a glove box filled with argon, Ti powder and CH₄N₂And putting the O into a WC hard alloy ball milling tank. The mass ratio of the balls to the materials is 20: 1. Three large, medium and small WC hard alloy balls with the diameters of 8mm, 5mm and 2mm respectively are used, and the mass ratio of the large, medium and small WC hard alloy balls is 3: 1. Ball milling is carried out on a planetary ball mill (QM-3SP4 type, China) for 60 hours, the mill is stopped for 30min every 2 hours for heat dissipation, and the rotating speed is set to be 450 r/min.

TiN_0.3(self-made) and TiC (commercially available, granularity of 1-3 μm, purity of more than 99%) are proportioned, and ball milled for 30min by a planetary ball mill (QM-3SP4 type, China) with a ball-material mass ratio of 10: 1, the ball milling tank is a WC hard alloy tank (250ml), and the diameters of the WC hard alloy balls are respectively equal to that of the WC hard alloy tank8mm and 5mm, the mass ratio of the big ball to the small ball is 6: 4, and the rotating speed is set to be 300 r/min. Then water and organic binder CMC are added for spray granulation to obtain composite powder with the average grain diameter of 35 mu m.