Plasma-sprayed strontium zirconate coatings

Abstract

SrZrO3 is used as the best suit for thermal barrier coatings, where it is used as the topcoat. In this study, SrZrO3-based plasma spray coating powders were produced by sintering and crushing method from zirconia and strontium carbonate. The mixture of zirconia and strontium carbonate powders with an atomic ratio of Sr/Zr to 1.136 was ground in a zirconia ball mill. To increase powder fluidity, the mixture of powder was sintered with a heating rate of 10 °C/min for 24 h at 1250 °C, 1350 °C and 6 h at 1600 °C. Sintered SrZrO3 powders were screened to optimum particle size range and coated onto AISI 304L stainless steel surfaces by atmospheric plasma spray coating technique. Thermal shock tests of the SrZrO3 coated samples were executed at 1000 °C and 1200 °C for 5 min (heating) and then for 2 min cooling cycle at room temperature. The radiation attenuation properties of strontium zirconate-coated steel substrates were investigated. The linear attenuation coefficients of the SrZrO3-coated specimens were carried out for Cs-137 and Co-60 gamma radiation sources. The resulting coating powders and coatings were characterized using SEM–EDS and XRD techniques. In conclusion, the gamma shielding properties of the stainless steel substrates increased by coating.