Using of Pulsed Nd-Yag Laser in the Treatment of Thermal Spray by Aluminum and Diffusion Coating Phases of Low Alloy Steel


High power pulsed Neodymium doped Yttrium Aluminum Garnet-(Nd– YAG)- laser with 1J power was used to fuse coatings containing a mixture ofFeAlO and Al. This mixture produced by aluminizing pack cementation treatmentand thermal spray of low alloy steel, That is for Studying the mechanical ,surface and metallurgical properties for each coating system , and to make acomparison before and after irradiation , and also the specified properties includingthe coating thickness . Aluminum Coated samples were made by two advancedtechniques pack cementation and thermal spray methods in order to compare theresulted coating layer properties before and after irradiation, and also to determinethe technique role from one hand ,also fusing effect and thermal residual stressesrole which resulted from irradiation in the variation of studied properties on theother. Results showed that pack cementation coating layer has roughness, Microhardness and wear resistance higher than thermal spray coating layer. Irradiationresults was showed an improvement in studied properties, this was attributed to thefusing, thermal residual stresses and laser rays role in refining the grains which arein conjunction with finer microstructure . After irradiation a formation of a hardphase (martensite) was recorded, this was attributed to the sufficient percentage ofcarbon (0.4%) in the selected alloy, this was enshured by microstructure imagestaken by optical microscopy. X-ray diffraction showed, for laser surface irradiatedcoating layers, presence of the phase due to interaction between the base metalconstituents. A modification of coating phases composition could be concluded forboth coating techniques. Also the two techniques illustrate a formation of coatinglayer with a different thickness.