Effect of (La0.8Sr0.2)CrO3 Coating on Carbon Deposition onto a Stainless-Steel (SUS430) Substrate

In this study, a dense strontium-doped lanthanum chromite (La_0.8Sr_0.2CrO₃, LSC) thin layer was designed to protect a stainless-steel (SUS430) substrate from carbon deposition. The LSC layer was coated onto an SUS430 substrate by a dipping technique from a precursor solution of La, Sr and Cr nitrates, acetylacetone (acac), and 2-methoxyethanol. The effect of AcAc on the phase behavior and microstructure evolution of the LSC thin films was investigated. After being heat-treated at 800°C in air, the thin film was found to consist of perovskite LaCrO₃, Mn_1.5Cr_1.5O₄, and Cr₂O₃ phases. The addition of a chelating agent, acac, to the precursor solution led to a reduction in the formation of the strontium chromite (SrCrO₄) phase. As a consequence, a thin film having a dense microstructure could be obtained. It was confirmed by Fourier-tranform Raman spectroscopic analysis and FESEM observations that the carbon deposited on the uncoated SUS430 substrate was amorphous with a spherical morphology. The LSC thin film thus obtained was found to be very effective at preventing carbon deposition when it was heat-treated under a dry hydrocarbon atmosphere.