Product Code: ICAL06_M802

Tribaloy-800 Coatings on Steel Substrates by Means of Laser Cladding: Dilution Effects on the Microstructure and Coating Performance
Authors:
Armando Yanez, Universidade Da CoruFerrol Spain
Jose Carlos Alvarez, Universidade da Coruña; Ferrol Spain
Jose M. Amado, Universidade da Coruña; Ferrol Spain
Maria Tobar, Universidade da Coruña; Ferrol Spain
Presented at ICALEO 2006

The Co-Mo-Cr-Si alloys, mostly known as Tribaloy family, combine outstanding properties in terms of wear and corrosion resistance as well as in terms of mechanical strength. Compared with other wear resistant alloys, which generally gain their strength and hardness from hard phase mixed carbides precipitates, Tribaloy properties are due to the alloying elements Mo and Si which promote the formation of a hard and corrosion resistant structure known as Laves Phase.In this work, protective Tribaloy (T-800) layers were deposited on an austenitic steel AISI304 substrate by means of laser cladding. The microstructure of the layers, about 1-2 mm thickness and 800-1100 HV hardness, was inspected by means of SEM/EDX and its wear performance evaluated according to ASTM standards.
Dilution being a difficult factor to control in industrial laser cladding operating conditions, the effect of Fe additions on the coating from dilution with the substrate was specially investigated. Iron additions between 7% to 20%(wt.) were found to stabilize the fcc form of the cobalt solid solution, giving a fully eutectic matrix and decreasing the volume fraction of the primary Laves phase. However, no significant differences were observed in the wear performance of the coatings while its hardness is slightly enhanced.