Surface modification of 347 stainless steel by rapid mirror scanning of a high power CO₂ laser Available to Purchase

A surface modification technique that uses a 1 kW CO₂ laser beam actuated by two high speed raster-scanning mirrors was utilized to selectively consolidate pre-deposited coatings consisting of 50Cr-50Ni (wt.%) over the surface of 347 austenitic stainless steel specimens. The oxidation resistance of the coated specimens was evaluated by heating them in air at 750°C for 300 hours. The migration behavior of the coating elements was also studied. Comprehensive characterization of the samples was performed using scanning electron microscopy (SEM), energy dispersive spectrochemical analysis (EDS), and optical metallography. The surface protective coatings produced by this technique demonstrated a metallurgical bond with homogeneous dilution, low porosity, and constant thickness. Exposure to high temperature initiated migration of coating species towards the bulk preferentially by means of grain boundary diffusion. The research demonstrates that surface modification by high-speed selective raster-scanning of a high-power laser beam is a versatile and expedient technique that can be used for applications that require large surface area coverage for oxidation protection.