Industrial coatings comprise epoxy, phenolic, silicone, and urethane, but increasing demands for performance have ushered in new materials and process advancements in the industrial coatings marketplace.
Surfaces susceptible to abrasive or erosive wear, extreme heat, corrosion, or require dimensional restoration or electrical insulation, as examples, can benefit greatly from high-velocity oxygen fuel (HVOF) type coatings. Developed in the 1980s, this branch of thermal spray coatings brings surface property enhancements that may include: adhesive strength, hardness, and resistance to abrasion or permeation, using a wide range of alloyed metals and ceramic powders transformed right into a plasticized state while fed via a warm gas stream.
Also known as “wire flame spray” or the “combustion wire coating process”, the procedure utilizes an oxygen-fuel gas flame for the heat source. Both the wire form and solid rod feed-stock are utilized.
The outermost tip of the wire or rod is melted because it passes through the flame and is “atomized” into really small particles by way of a surrounding jet of compressed air, propelled to the work-piece to make the coating at the surface.
Substrate temperatures remain comparatively low in the HVOF coating process, little heat is imparted to the work-piece, so the danger of distortion from heat is minimal, no more than a few hundred degrees F, typically, making most metals suitable for the coating process, containment coating including iron, steel, austenite or martensite grades of stainless steel, alloys of copper and aluminum. Builds (coating thickness) as high as 0.250 inches are attainable.
Additionally, the RoHS compliance of HVOF coatings brings significant advantage over metal finishing processes such as for example hard chrome plating.
Markets for high-velocity oxygen fuel (HVOF) industrial coatings include automotive, medical, defense and aerospace, printing and paper, food processing, industrial and manufacturing, military, aerospace and defense, and more.
Restoring surface dimensions of worn components is really a common usage of this coating process. However, uses involving line or point contact, shear loads, higher stress, must certainly be avoided, such as for example gear teeth, splines or threads.
For newly-engineered surfaces requiring performance solutions to abrasive wear, HVOF coatings based on tungsten carbide can be an excellent choice. In applications of surface fatigue, motion between contacting areas, overcoming friction concerning wear, molybdenum can serve well.
Thermal spray coatings can solve a variety of issues relating mechanical, electrical, or corrosion. However, remember that no strength is put into the bottom material. Surfaces must be able to withstand the mechanical loads in service; nitride or heat treat as needed.