Comparisons between plasma and laser deposited coatings made with traditional filler materials and new alloys

Abstract

Abstract Technologists and metallurgists are constantly researching alloys and techniques capable of meeting increasing wear and corrosion resistance and coating quality requirements. This article describes the results of a vast series of tests carried out to compare different coating techniques using various processes: TIG, plasma and laser. A special comparison is made for the following plasma techniques with filler material in powder form: non-transferred arc (spray type) plus refusion, transferred arc and semi-transferred arc. The tests were performed using traditional materials, such as cobalt based and nickel-boron based alloys, and a special nickel based boron-free alloy. Mechanical and tribological tests showed the competitiveness of the new nickel based boron-free alloys, particularly in nuclear applications at high radiation levels and in highly corrosive environments such as marine locations. The non-transferred arc plasma technique, associated here with refusion through electromagnetic induction, produced a coating of excellent durability and quality. The laser coating technique is also particularly promising.