Novel Diode Laser Cladding of High Temperature Alloys for Used in Ultrasupercritical Coal-Fired Boilers

Years of industrial investment have yielded nickel-based, austenitic, and new ferritic alloys, which have been designed to meet the creep resistance demands, of ultrasupercritical coal-fired boilers. These developments have contributed to record high commodity prices for nickel and chrome. Now, the high operating temperatures ¿ along with the oxidizing, corroding, and slag-deposition-induced microclimate environments ¿ of low NOx combustion systems have generated a critical need for new cladding techniques. These new cladding techniques must be cost effective ¿ that is, they must reduce the amount of the special creep resistant alloy materials and simultaneously improve the alloy material performance. This project will develop novel cladding processes based on the use of a high-power direct-diode laser, the smallest and most efficient laser in the world today. The diode laser will enable the welding of very thin, smooth, low-slag-adhesion clad layers of creep resistant alloys onto steel substrates, with little or no dilution, with low distortion, and at very high deposition rates. Commercial Applications and other Benefits as described by the awardee: The new cladding techniques should result in improved clad material properties, reduction in coal-fired boiler costs, and increased boiler efficiencies, thereby reducing pollution and carbon dioxide emissions. For military applications, the technology should enable the laser-cladding repair of armored systems.