Tungsten Carbide Thermal Spraying Powder with High Bonding Strength

Tungsten carbide-based cermets are widely used in aerospace, metallurgy, petrochemical, mechanical and other industries because of their high hardness, good toughness and good comprehensive properties. The common tungsten carbide-based cermets for thermal spraying include WC-12Co, WC-17Co, WC-10Co4Cr, WC-CrC-Ni, WC-Ni, etc. WC is a hard wear-resistant phase and Co, CoCr or Ni is a metal bonding phase.

Based on the problems existing in the existing technology, a preparation method of tungsten carbide thermal spraying powder for preparing high bonding strength and low porosity coatings is proposed, which can be used for high-requirement tungsten carbide thermal spraying operation, including the following steps:

Step 1: Configure slurry: Using tungsten carbide based cermet powder, metal powder (optional aluminum powder, molybdenum powder, titanium powder), polyvinyl alcohol and deionized water as raw materials, mix metal powder, polyvinyl alcohol and deionized water evenly, and stir to form metal powder slurry;

Step 2, the disposed metallic powder slurry and the tungsten carbide-based cermet powder are mixed evenly to form a mixed powder.

Steps 3: Drying and sintering: Mixed powders are dried in an oven at 100 ℃, then sintered in a vacuum furnace or an inert atmosphere furnace. The sintering temperature is 540 - 630 ℃ and the sintering time is 1 - 2 hours.

Step 4, the sintered powders are screened to obtain tungsten carbide thermal spraying powder for preparing high bonding strength and low porosity coatings.

Tungsten carbide powder with high bonding strength and low porosity can be prepared by the process. The bonding strength of the coating is 35-60 Mpa when plasma spraying is used, and the porosity of the coating can be below 4%. When supersonic flame spraying is used, the porosity of the coating can be below 0.6%.

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