Arc sprayed amorphous alloys have risen in popularity for a variety of applications. An amorphous alloy has a “glasslike” structure rather than crystalline. They are very hard (50-70 HRC) and have an extremely low coefficient of friction. As a result, they are very effective for sliding and abrasive wear.
Polymet manufactures a number of amorphous materials for our arc spray wire product line. The wires are cored wires, often called flux cored wires. They utilize a special powder formulation placed inside of a metal sheath. These are generally FeCrBSi based alloys such as Vecalloy B, PMET 273, PMET 270 and 296. They all offer excellent wear and corrosion resistance, when arc sprayed.The most effective of these alloys has proven to be Vecalloy B. It also has close to double the bond strength of the other alloys, allowing thicker coatings when needed, without spalling or cracking. The addition of nickel to the alloy gives it better corrosion resistance compared to other amorphous alloys.
Applications where amorphous alloys have proven effective include boiler tubes in coal fired boilers, dryer rolls in the pulp & paper industry, auger screws for grain and hydraulic shafts.