“Metal spray” or “thermal spray” are generic terms which can refer to a number of processes, including thermal arc, flame spray, plasma spray and HVOF. “Metal spray” is often used to describe thermal arc spray, and some coating providers may purposefully use the term “metal spray” so as not to specifically allude to their process.
Thermal arc is a cheap, low-energy process, and the coatings are normally quite porous compared to high-energy coatings like HVOF (which have low porosity). The high porosity of thermal arc sprays provides a lower-density coating compared to HVOF, as well as lower resistance to environmental or chemical aggressors (ie. a mode of corrosion), allowing more opportunity for liquids, vapours and gases to permeate the coating to the substrate.
Though the price might be more attractive than a HVOF coating, thermal arc is not usually recommended for hydraulics or sealing surfaces, and the coatings provide inferior performance (compared to high-energy sprays) on bearing surfaces. The various coating processes and materials are suited to different applications, so chat to HVT today for your custom coating solutions.