La_2Zr_2O_7 (LZ) COATINGS BY LIQUID FEEDSTOCK PLASMA SPRAYING: THE ROLE OF PRECURSORS

摘要

Solution precursor plasma spraying (SPPS) is an innovative process for obtaining finely structured coatings from metallic salt solutions. Lanthanum and zirconium precursors were studied in order to understand their influence on the synthesis of lanthanum zirconate (La_2Zr_2O_7) by SPPS. Thermal analysis revealed that the nature of the precursor affected the hydration shell as well as the formation temperature of zirconium oxide (ZrO_2). The surface tensions of precursor solutions in various media were investigated and revealed the influence of the nature of the anion. Different solutions of precursor mixtures were used to obtain La_2Zr_2O_7 splats on metallic substrates. A decrease in the surface tension of the solution led to an increase in the size of the splats. Coating mechanisms by SPPS are governed by the nature of the precursors and solvents.