Lanthanum Chromite Coating on Stainless Steel by sol–Gel Dip Coating Technique

Rashtchi, Hamed | 2010

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 41071 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Faghihi Sani, Mohammad Ali
  7. Abstract:
  8. Because of the high operating temperature, interconnect surface tends to be oxidized and Cr2O3 oxide layer will be created on the surface. This phenomenon is undesirable due to decreasing electrical conductivity, so a preservative coating is needed to improve the interconnect properties. In this paper, a dense perovskite thin film was successfully synthesized on a ferritic stainless steel (type 430) substrate by a sol-gel dip coating method. This coating improved chemical stability, oxidation behavior of the substrate and decreased cathode poisoning. The lanthanum chromite was coated on the substrate by sol-gel dip coating process. First, during a hydrolyze process, a stable sol was made up from lanthanum chromite precursor. The substrate was immersed in the sol and then was pulled out with a specific speed to form a thin gel layer on it. Finally, a lanthanum chromite layer (with or without dopant) was created on the substrate with a heating process. The optimum calcination temperature was measured 800°C by using XRD, STA and FTIR analysis on synthesized powders through a calcination process. Effect of strontium and calcium doping on coating properties was also evaluated. Eventually, microstructure, oxidation behavior and electrical properties of the coatings were investigated. It was observed that calcium doping had the most improvement on both oxidation behavior and electrical conductivity of the substrate
  9. Keywords:
  10. Lanthanum Chromite ; Sol-Gel Method ; Coating ; Stainless Steel ; Dipping ; Solid Oxide Fuel Cell (SOFC) ; Interconnect

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