High-temperature corrosion and mechanical properties of protective scales on Incoloy 800H: The influence of preoxidation and ion implantation

Abstract

Coatings, obtained by preoxidation of Incoloy 800H at low P02 show good sulphidation resistance due to the higher chromia content in the oxide scale. Yttrium-ion implantation of Incoloy 800H has also a beneficial effect on sulphidation, if preoxidation is applied. The reason for this is presumably the segregation of yttrium to grain boundaries of the oxide. Furthermore, the oxidation kinetics of Incoloy 800H are independent of the partial pressure of the oxygen. Mechanical testing of the preformed oxide scale/substrate combinations in air at 600~ by means of constant-extension-rate experiments shows that preoxidation at low partial pressures of oxygen leads to earlier scalecracking.

High‐temperature corrosion behavior of some post‐plasma‐spraying‐gas‐nitrided metallic coatings on a Fe‐based superalloy

“…In the case of uncoated Superfer 800H superalloy, the oxide phases found are Fe 2 O 3 , Cr 2 O 3 , NiO, NiCr 2 O 4 , and NiFe 2 O 4 . The results of X‐ray mappings analysis, as shown in Figure a, for the oxidized superalloy Superfer 800H is in good agreement with those reported by Polman et al for a similar superalloy Incoloy 800H. The presence of Cr 2 O 3 and NiO in the top scale of bare superalloy is supported by the surface color of these samples after oxidation studies, which is blackish green.…”

“…In the case of uncoated Superfer 800H superalloy, the oxide phases found are Fe 2 O 3 , Cr 2 O 3 , NiO, NiCr 2 O 4 , and NiFe 2 O 4 . Furthermore, the X‐ray mappings, as show in Figure a, for the oxidized bare superalloy Superfer 800H are in good agreement with those reported by Polman et al for a similar superalloy Incoloy 800H. Further, the main phases identified for the TiAlN coating are Al 2 O 3 , Ti 2 O 3 , and NiO.…”

High Temperature Oxidation Behavior of TP304H Steel Coated with CeO2 in Water Vapor

“…Several explanations have been given about the REE [5][6][7][8]12]: (a) nucleation of chromium oxide at the reactive element oxide particles; (b) blocking of short-circuit diffusion paths by segregated reactive element ions resulting in a modification of the diffusion mechanisms, which changed from predominant outward cation transport to inward anion transport; (c) reduction in the stresses in the scale resulting from changes in its growth process and microstructure. Chevalier et al studied the oxidation of Nd 2 O 3 coated F17Ti steel in air and located the rare-earth element in the external part of the oxide scale [13].…”

“…The beneficial effects of reactive element additions on the oxidation resistance of heat resistant alloys are well known [3][4][5][6][7][8]. Small amounts of reactive elements (such as rare earth elements) clearly improve the oxidation resistance of chromiaforming alloys, usually called reactive element effect (REE).…”

Surface modifications of AISI 420 stainless steel by low energy Yttrium ions

“…clearly improve the oxidation behaviour of chromia-and alumina-forming alloys [6][7]. Several explanations are given about this effect, usually called reactive element effect (REE), namely a modification of the diffusion mechanisms, a reduction of vacancies condensation at the internal interface, a formation of reactive element oxide inclusions trapping alloy impurities [8][9][10]. In this work, thermal treatment was carried out in order to study the influence of implanted yttrium on the oxide scale adherence on 410 steel specimens oxidized at 1123K.…”