Hard arc-sprayed coating with enhanced erosion and abrasion wear resistance

A cored wire formulation, referred to as Alpha 1800, has been developed to produce tailored arc-sprayed coatings that are tough enough to resist particle impacts at 90 deg and sufficiently hard to deflect eroding particles at low impact angles. One millimeter thick coatings composed of ductile and hard phases with a Knoop hardness reaching 1800 kg/sq mm were easily produced by arc spraying the cored wire with air. Coatings were (1) erosion tested at 25 C and higher temperatures at impact angles of 25 and 90 deg in a gasblast erosion rig, (2) slurry erosion tested at impact angles of 25 and 90 deg, and (3) abrasion wear tested using the ASTM G-65 test procedure. Results show that coatings produced with the new cored wire are at least five times more erosion resistant and 10 times more abrasion resistant than coatings produced by arc spraying commercial cored wires. The performance of the new arc-sprayed coating can be compared with that of high-energy WC-based coatings. Maintaining their erosion resistance after being exposed to temperatures up to 850 C and possessing good oxidation resistance, arc-sprayed coatings produced with the new cored wire are attractive for applications in many industrial sectors involving high temperatures. (Author)