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Brief introduction for HVOF spraying process

Time : 2022-08-02 Hits : 6

High velocity oxy-fuel (HVOF) spraying works by mixing fluid fuel and oxygen, which is fed into a combustion chamber and ignited. The resultant gas has an extremely high temperature and pressure, which is ejected through a nozzle at supersonic speeds. To the high velocity gas stream, powder is injected, which partially melts. The stream of hot gas and powder is directed towards the surface to be coated. The resulting dense coating has low porosity and high bond strength [1], providing many benefits such as corrosion resistance.  

The characteristics of HVOF spraying are: high jet velocity, lower flame temperature than explosive spraying, suitable for carbide coating.  HVOF spraying is primarily used to apply high quality coatings of cermets such as WC/Co and WC/Co/Cr.  Coating thickness is usually in the range 0.1-2 mm.  Characteristic features of HVOF sprayed coatings include their low level of porosity at about 1-2vol% and low oxide content in the range 1-2wt%.  The bond strength often exceeds 80MPa.  These coatings can be used across a spectrum of engineering and manufacturing applications to enhance the surface properties of components.  This allows preparation of cost effective, high performance parts made from low cost or lightweight materials with a functional surface.

High Velocity Oxygen Fuel (HVOF) spraying is a thermal spray coating process, which is used to improve or restore a component's surface (properties or geometry). This surface engineering technique better enables life extension of equipment by increasing erosion and wear resistance, and corrosion protection.  HOVF spraying is a widely used process in the field of cemented carbide production. The use of supersonic spraying technology can strengthen the surface strengthening treatment of cemented carbide parts, making it more suitable for harsh working conditions in various industries such as machinery manufacturing, aerospace, transportation energy, and petrochemical industries.

Advantages of HVOF spraying over other thermal spray processes primarily relate to improved coating quality,
such as:

Higher strength bond to the underlying substrate and improved cohesive strength within the coating
Better wear resistance due to harder, tougher coatings
Higher hardness due to less degradation of carbide phases
Improved corrosion protection due to less through thickness porosity  
Thicker coating due to less residual stresses   
In recent years, with the further improvement of people's requirements for coating performance, the majority of scientists have developed supersonic flame spraying and supersonic plasma spraying on the original basis through continuous innovation. At the same time, they have successively developed laser spraying, reaction heat spraying Processes such as spraying and cold spraying.
Zonco has a variety of surface strengthening technologies, including rich experience in supersonic spraying, to provide customers with solutions to various difficulties. For more products details, please visit website: https://www.zonco-carbide.com/