Silicon carbide coatings on zirconium alloy for light water reactor fuel cladding studies

Coating of zirconium alloys is a promising approach for improving various properties of the cladding of fuel elements, including physical, mechanical properties, corrosion resistance and reduction of radiation damage. In this paper, SiC coatings with thicknesses of 100, 200, and 300 microns were deposited by selective laser sintering (SLS) on Zr-1Nb alloy substrates at a laser power of 150 W. The 200 μm layer deposition registered the least contact depth during macro-scratch test to a maximum depth of about 25 μm into the coating. The uniformity and less porosity of the coatings is observed on the transverse sections in the entire variant. Analysis of the phase composition of the coating revealed the formation of silicon carbide phases (6H & 4H), with protective oxides of Al2O3, Y2O3, SiO2 and YAlO3. High coating adhesion was noticed with results of the scratch tests showing no delamination regardless of the higher loads used. However, partial chippings and transverse cracks were observed. The results obtained indicate the need for further research to improve the porosity of the surface structure of the coating and to conduct other necessary tests.