HIGH VELOCITY OXYGEN FUEL

'High Velocity Oxy-Fuel' (HVOF) is a thermal spray technique used to deposit protective coatings on a substrate.

Contents

HVOF Process

Applications

Literature

External links

HVOF Process

A blend of fuel (gaseous or liquid) and oxygen is injected into a torch and burned. The combustion products flow through a nozzle that accelerates the flow to a speed up to 1500 m/s. A powder feed stock is injected into the gas stream, which accelerates the powder up to 800 m/s. The stream of hot gas and powder is directed towards the surface to be coated. The powder partially melts in the stream, and deposits upon the substrate. The resulting coating has low porosity as and a high bond strength.
HVOF coatings may be as thick as 12mm (1/2"). It is typically used to deposit a wear and corrosion resistant coatings on a material. Ceramic and metallic powders can be deposted using HVOF. Common powders include WC-Co, Chromium carbide, MCrAlY, and alumina.

Applications

★ Aluminide coatings

★ Bond coats for Thermal barrier coatings

★ Hard facing

★ Hydroxyapatite (HA) coatings for medical implants

★ MCrAlY coatings

Literature

★ "Protective coatings for titanium aluminide intermetallics", R.L. McCarron, J.C. Schaeffer, G.H. Meier, D. Berztiss, R.A. Perkins, J. Cullinan, in Titanium '92 - Science and Technology, edited by F.H. Froes and I. Caplan, 1992, TMS:Warrendale, PA, p. 1971-1978.

External links

★ www.ellisonsurfacetech.com, company providing HVOF coatings

★ www.precisioncoat.com, commercial company in various coatings (also used as a source for this article)

★ www.thermisch-spuiten.nl, short explanation of the process (text in Dutch, explaining figure in English)

★ www.aludra.nl, short explanation of the process