High temperature oxidation of two- and three-dimensional hafnium carbide and silicon carbide coatings

Abstract

International audienceThe difficulty in using above 2000°C in an oxidizing atmosphere C/C composites as structural components is their poor life time. The solution proposed here consisted in combining two refractory carbides, hafnium and silicon carbides, in coating with a complex architecture, named a three dimensional coating, over a C/C substrate. Such a coating protects the C/C composite at 2050°C under air. The oxidation of the coating leads to the formation of a Si x O y Hf z hafnium-containing silicate liquid, combined with HfO 2(s). This liquid limits oxygen diffusion more than pure SiO 2 does, so it is a better protection against oxidation. Furthermore, HfO 2(s) acts as a grip holding Si x O y Hf z in place. From these results, an oxidation mechanism is proposed and discussed

Response of 4H-SiC Detectors to Ionizing Particles

“…The high threshold displacement energy of the material leads to a high level of radiation hardness compared with other common semiconductor detector materials [4,5], whereas the strong covalent bonds between atoms also makes the materials mechanically strong. Due to its radiation hardness, fast switching-capability, insensitivity to visible light, and biocompatibility, SiC is used for many other applications such as radiation hard electronics, high temperature coatings, biomedical sensors, UV-light sensors and others [6][7][8][9]. The radiation detectors based on 4H-polytype SiC epitaxial layers are mostly used as a charged particle [10,11] and neutron detectors [12].…”

Large‐scale synthesis of hafnium carbide nanowires via a Ni‐assisted polymer infiltration and pyrolysis

“…As a functional material, HfC is mainly used as cathode material in field emission due to its unique electronic characteristics . As a structural material, HfC has been used as ultra‐high–temperature thermal protective coatings and additive components of C/C composite due to its good mechanical performance and high physical and chemical stability.…”

Effect of Monolithic LaB6 on the Ablation Resistance of ZrC/SiC Coating Prepared by Supersonic Plasma Spraying for C/C Composites

“…However, these applications are limited by their rapid oxidation or ablation at ultra-high temperatures [4][5][6][7] . Ceramic coatings are designed to protect C/C composites from oxidation or ablation [8,9] .…”