Surface Alloying of Ceramic Powders on Ferrous Substrates Using Concentrated Solar Energy

摘要

The possibility of surface alloys formation and their characterization with pre-deposited ceramic powders (SiC and Cermet: WC + 17% Co) on steels, using concentrated solar energy was studied in this work. The experiments were carried out at "Plataforma Solar d' Almeria" in South Spain, in terms of a "Large Scale European Research Facilities-TMR" program. The microstructure of the treated surfaces was studied by means of optical and electronic microscopy, while results of microhardness measurements and friction-wear tests were also obtained. The treated zones presented microstructural inhomogeneity and their hardness varied from 600 to 1900 HV_(300p) , depending on the duration of their solar exposures. Thus, long exposures (20-30 min.) drove into deep treated zones (3-6 mm) and low hardness values, whereas short heating times (<10 min) resulted in small depths of the treated zones (1-2 mm), great amount of undiluted and partially diluted carbides and, therefore, higher hardness values. The friction coefficient was found decreased from 0.7 of the untreated to 0.5 of the treated surface, while the loss of mass of the untreated steel was 3 times higher than the treated, in case of SiC and 5 times higher in case of Cermet.