Effect of mixed nanocrystalline rare earth oxide coatings on high temperature oxidation of a ferritic stainless steel AISI 409
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2019
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BRAZIL MRS MEETING, 18th
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Resumo
Rare earths (RE) have been used to improve the high temperature oxidation
resistance of chromium dioxide and alumina forming alloys. The RE can be added
to the alloy as elements or as oxide to form dispersions. It can also be applied as a
RE oxide coating on the surface of the alloy. In this investigation the sol-gel
technique was used to prepare sols of the RE oxides as it produces
nanocrystalline oxide particles. In an effort to increase further the oxidation
resistance of high temperature alloys, optimization of RE oxide additions to the
alloy surface was attempted. This paper presents the effect of nanocrystalline
oxide gel coatings of CeO2, Nd2O3, Pr2O3, CeO2 + Nd2O3, CeO2 + Pr2O3 and Pr2O3 +
Nd2O3 on the oxidation behavior of a ferritic stainless steel AISI 409 at 1000 °C in
air using a thermogravimetric balance. The morphology of the pure oxides was
studied and the following formats were observed: CeO2 – rods; Nd2O3 – platelets;
Pr2O3 – needles; La2O3 – cuboids. The average oxide particle sizes and the average
crystallite sizes were also determined. The oxidation rate of the coated steel
specimen was significantly less than that of the uncoated steel specimen, due to
formation of a fine layer of chromium dioxide at the steel/oxide interface. The
oxidation rates of the different REO coated steel specimens varied with the type
of REO. The mixed oxide containing Pr2O3 increased significantly the oxidation
resistance of the steel. The CeO2 + Nd2O3 mixture did not increase oxidation
resistance of the steel further, compared to those with either one of these two
rare earth oxides. The differences in the influence of a specific rare earth oxide or
a mixture are attributable to differences in the ionic radii of the RE and the
morphology as well as the crystallite sizes of the RE oxides.
Como referenciar
RAMANATHAN, LALGUDI V.; FERNANDES, STELA M.C.; CORREA, OLANDIR V. Effect of mixed nanocrystalline rare earth oxide coatings on high temperature oxidation of a ferritic stainless steel AISI 409. In: BRAZIL MRS MEETING, 18th, September 22-26, 2019, Balneário Camburiú, SC. Abstract... São Carlos, SP: Aptor Software, 2019. p. 414-414. Disponível em: http://repositorio.ipen.br/handle/123456789/31038. Acesso em: 12 Mar 2025.
Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.