Effect of Powder Injection Location on Ceramic Coatings Properties When Using Plasma Spray

Abstract

The effect of powder injecting location of the plasma spraying on spraying properties was studied. Three different powder-injecting methods were applied in the experiment. In the first method, the particles were axially injected into the plasma flow from the cathode tip. In the second method, the particles were radially injected into the plasma flow just downstream of the anode arc root inside the anode nozzle. In the third method, the particles were radially injected into the plasma jet at the nozzle exit. The alumina particles with a mean diameter of 20 lm were used to deposit coatings. Spraying properties, such as the deposition efficiency, the melting rate of the powder particles, and the coating quality were investigated. The results show that the spraying with axial particle injecting can heat and melt the powder particles more effectively, produce coatings with better quality, and have higher deposition efficiency.

Study on the Tribological Properties of Low-Power Plasma-Sprayed Al-Cu-Cr Quasicrystalline Coating

“…2.1 Plasma Spraying Equipment. The low power plasma spraying equipment with an axially-fed powder system used in this experiment was developed by Dalian Maritime University [11,[13][14][15]. It is generally operated in an input power ranged from 2 to 15 kW, which is much lower than an input power of 40-200 kW for the traditional plasma spraying with an externally-fed powder system.…”

“…In the present study, the Al-Cu-Cr QC coatings were prepared by a new APS equipment with axially-fed powder system [11,[13][14][15]. The influence of H 2 content in the working gas on the phase composition, microstructure and tribological properties of the coatings was investigated.…”

Researches Structure and Properties of Self-Fluxing Coating, Obtained by Air-Plasma Spraying

“…Today the most common method of powder injection into the plasma jet is cross point injection through the tube charge-line on the end of the outlet nozzle or through an orifice in the nozzle [5][6][7]. This method of injection contributes to the emergence of heterogeneity fields of the temperature and velocity of the plasma jet.…”

Technique of Formation of an Axisymmetric Heterogeneous Flow During Thermal Spraying of Powder Materials

“…By now, the conventional technique of injection of a processed powder material into a thermal plasma jet generated by a commercial plasma torch is the point transverse injection (usually at an angle of 90°to the plasma jet axis) through a tube flux duct at the nozzle exit or through an orifice in the nozzle (Ref [1][2][3][4]. This kind of powder injection significantly disturbs the carrier flow, which enhances the interaction between the plasma jet and the ambient medium, thus, resulting in fast dissipation of energy in the high-temperature area of the jet and in distortion of the radial temperature profile.…”