Preparation method of dense tungsten coating

A coating and densification technology, applied in the direction of coating, metal material coating process, melting spray plating, etc., can solve the problems of not meeting the requirements of tungsten coating, low coating density, easy oxidation of powder, etc. The effect of resistance to thermal radiation and thermal shock, high bond strength and low porosity

Inactive Publication Date: 2012-04-04
UNIV OF SCI & TECH BEIJING
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Problems solved by technology

The disadvantage is that there are defects such as pores and cracks in the coating, and the coating density is low.
At the same time, the coating and the substrate are mechanically bonded, and the bonding strength is poor. The powder is easily oxidized during the spraying process, which cannot meet the requirements of the tungsten coating under high irradiation and high thermal shock conditions.

Method used

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  • Preparation method of dense tungsten coating
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  • Preparation method of dense tungsten coating

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preparation example Construction

[0022] A preparation method of dense tungsten coating, the method is carried out as follows:

[0023] First, fine tungsten powder is selected as the raw material, and it is dried in a vacuum oven at 90°C for later use to avoid the problem of powder agglomeration during the spheroidization process. Using radio frequency plasma as the high temperature heat source, before preparing the tungsten coating, pre-evacuate the vacuum chamber with a vacuum degree of 1×10 -3 Pa, to prevent oxidation of powder and coating.

[0024] Establish a stable plasma torch. The working power of the plasma torch is maintained at 30-75KW, the flow rate of the argon working gas is 20-45 slpm, the flow rate of the input argon protective gas is 20-110 slpm, and the pressure in the chamber is 200 when the RF plasma system is running. ~300mm Hg. The tungsten powder is sent into the plasma high temperature zone with argon as the powder carrier gas, the flow rate of the powder carrier gas is 3.5~10slpm, an...

example 1

[0026] Example 1: Preparation of tungsten coating from tungsten powder with an average particle size of 5 μm

[0027] The substrate is made of Φ40mm×8mm stainless steel, pre-treated by sandblasting, and then cleaned with alcohol to obtain a clean and rough surface. Tungsten powder with an average particle size of 5 μm was dried in a vacuum oven at 90°C for 45 minutes before use. The vacuum chamber is pre-evacuated to 1×10 -3 Pa. Using argon as the working gas and shielding gas to establish a stable radio frequency plasma torch, the plasma torch operating power of the equipment is 45KW, the flow rate of the argon working gas is 28slpm, the flow rate of the argon shielding gas is 60slpm, the radio frequency plasma system The pressure in the chamber during operation is 200 mm Hg. The tungsten powder is fed into the plasma high temperature zone with argon gas with a flow rate of 4 slpm, the feeding rate is 5g / min, the distance between the RF plasma tail flame and the substrate ...

example 2

[0028] Example 2: Preparation of tungsten coating from tungsten powder with an average particle size of 25 μm

[0029] With Φ40mm×8mm oxygen-free copper as the substrate, it is cleaned with alcohol and then pre-treated by sandblasting to obtain a clean and rough surface. Tungsten powder with an average particle size of 25 μm was dried in a vacuum oven at 90°C for 45 minutes before use. The vacuum chamber is pre-evacuated to 1×10 -3 Pa. Establish a stable radio frequency plasma torch with argon as the working gas and protective gas. The plasma torch operating power of the equipment is 55KW, the flow rate of the argon working gas is 30 slpm, the flow rate of the argon protective gas is 80 slpm, and the radio frequency plasma system is running The pressure in the chamber is 240mm Hg. The tungsten powder is fed into the plasma high temperature zone with argon gas with a flow rate of 5 slpm, the feeding rate is 25g / min, the distance between the radio frequency plasma tail flame ...

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Abstract

Belonging to the technical field of surface engineering, the invention provides a preparation method of a dense tungsten coating. The method is characterized in that: it takes ultrafine tungsten powder as a raw material, employs radio-frequency plasma as a high temperature heat source for providing sufficient heat, and adopts argon as a working gas and a powder carrier gas for conveying tungsten powder into a plasma high temperature area, while passing through the plasma high temperature area, the tungsten powder rapidly adsorbs heat and fuses, and the completely fused tungsten powder deposits, covers and solidifies on a matrix surface so as to form a dense tungsten coating. The method has the advantages that: radio-frequency plasma has high energy density so that powder can be totally fused and spheroidized, and the prepared tungsten coating has high density, low porosity, and high bonding strength with the matrix; meanwhile, the method has high powder utilization rate and low production cost. A tungsten coating prepared by the method of the invention has good thermal radiation resistance and thermal shock resistance, and is suitable for application in fields like plasma facing materials in nuclear fusion devices.

Description

technical field [0001] The invention belongs to the technical field of surface engineering, and in particular provides a method for preparing dense tungsten coating by using radio frequency plasma. [0002] Background technique [0003] Plasma Facing Materials (PFMs, also known as first wall materials) refer to materials that directly face high-temperature plasma in a fusion device and need to withstand high-energy particles and high heat shocks to protect the fusion device. In thermonuclear fusion devices, plasma-facing materials must not only withstand high thermal load requirements, but also meet the requirements of high-power energy deposition and high-energy ion irradiation during plasma rupture. Tungsten has the advantages of high melting point (3410°C), good thermal conductivity, low sputtering rate, high sputtering energy threshold, no reaction with hydrogen isotopes, good compatibility with plasma, and low corrosion rate. It is the most promising plasmonic materi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C4/12C23C4/08C23C4/134
CPCC23C4/08C23C4/134
Inventor 郭志猛盛艳伟郝俊杰林涛邵慧萍罗骥王玉明
Owner UNIV OF SCI & TECH BEIJING
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