Influence of LBE Temperatures on the Microstructure and Properties of Crystalline and Amorphous Multiphase Ceramic Coatings

Abstract

An Al2O3–TiO2 amorphous composite coating with a thickness of 100–120 μm was fabricated on China low activation martensitic steel (CLAM steel) by oxygen acetylene flame spraying technology and the laser in-situ reaction method. We investigated the microstructures and mechanical properties of the coating after liquid lead-bismuth eutectic (LBE) alloy corrosion under different temperatures for 300 h and found that the corrosion temperature of the LBE had no observable effect on the microstructure and chemical phase of the Al2O3–TiO2 amorphous composite coatings. However, the mechanical properties (micro-hardness and shear strength) of the Al2O3–TiO2 multiphase coating deteriorated slightly with the increase in the immersion temperature of the LBE. As a result of oxygen acetylene flame spraying and laser in-situ reaction technology, it was found that the Al2O3–TiO2 amorphous composite coating exhibits an excellent LBE corrosion resistance, which is a candidate structural material for the accelerator-driven subcritical system (ADS) to handle nuclear waste under extreme conditions.

Materials for Sustainable Nuclear Energy: A European Strategic Research and Innovation Agenda for All Reactor Generations

“…Higher swelling resistance is pursued via microstructure stabilisation with selected alloying elements (for instance AIM1 and its bettered version AIM2) [269][270][271]. Enhanced corrosion resistance is sought for with corrosion barriers, either by implanting aluminum to change the surface composition and induce the formation of a protective alumina layer [272,273], or by directly depositing alumina (or other ceramics) layers to coat the metallic substrate [274][275][276]. Alternatively, aluminum is added to the alloy composition, to enable the formation of a protective alumina layer that self-heals through contact with the oxygen that is contained in the circulating fluids, so-called alumina forming austenitic (AFA) steels [277][278][279][280][281].…”

A Review of the Surface Modifications for Corrosion Mitigation of Steels in Lead and LBE

“…However, the coating often exhibits low density and high porosity and contains numerous defects such as cracks or oxide inclusions. To overcome this disadvantage, Chen et al [54,55] combined successively the thermal spraying and the laser surface re-melting in-situ reaction technique in order to attempt having high quality coating Al 2 O 3 -TiO 2 on the Chinese low activation martensitic (CLAM) steel, a steel that contains 8.91% Cr, 1.44% W, 0.35% Mn, 0.15% Ta, and 0.13% C. First, a FeCrAlTi composite powder was obtained by ball milling, heating, stirring, and drying and broken treatment of a Cr-Fe, Fe-Al, and Ti powder. The oxyacetylene flame-spraying technology was applied first to fabricate the CrFeAlTi coating, and the laser in situ reaction compound technology was then adopted to prepare the composite ceramic coating using the CO 2 laser system.…”

“…A first trial in liquid lead for a duration up to 1000 h showed that the coating prevented Pb from diffusing and therefore featured potential applications in heavy liquid metals [54]. After exposure of the coated CLAM in LBE [55] without control of oxygen for 300 h at 450 and 550 • C, neither the Pb signal nor Bi signal were detected in the very surface of the CLAM steel. In addition, the Al 2 O 3 -TiO 2 coating exhibited a hydrophobic property on LBE, which is in favorable for LME resistance.…”

Environmental degradation of structural materials in liquid lead- and lead-bismuth eutectic-cooled reactors

“…Candidate coating materials that aim primarily at limiting and/or preventing undesirable LMC effects include refractory metals [180,243,626], Al-or Si-containing metallic alloys [192,525,596,[626][627][628][629][630][631][632], and certain ceramic materials [243,626,[632][633][634][635].…”