(also known as Thermal Spray) coating is a cost effective way to impart material properties to base materials and extend a part’s service life. Applications for this type of coating include wear prevention, dimensional restoration, thermal insulation and control, corrosion resistance, oxidation resistance, abrasive activity, and lubricating films.
Simply put, thermal spray coating is applied by spraying molten material at a high velocity onto a part where the material solidifies. Hohman uses two thermal spray process, Plasma spray and HVOF (High Velocity Oxygen Fuel). Plasma spraying uses an electric arc to ionize an inert gas, thus forming an extremely high temperature plasma. Powder forced into this plasma melts without decomposing. Resulting coatings are very dense and exhibit high bond strengths. HVOF, on the other hand, is a combustion process which results in very high gas streams, and hence, very high particle velocities. The temperatures are not as high as those obtained by plasmas, but the high kinetic energy compensates for the lower temperatures. Again, very dense, well adherent coatings are achieved.
Many thermal spray coatings are available, including but not limited to WCCo, Al2O3, NiCr, and PS304*.