Preparation of ZrB2-MoSi2 high oxygen resistant coating using nonequilibrium state powders by self-propagating high-temperature synthesis

• Published in: Journal of advanced ceramics 2021-10, Vol.10 (5), p.1011-1024
• Main Authors: Zhang, Menglin, Ren, Xuanru, Zhang, Mingcheng, Wang, Songsong, Wang, Li, Yang, Qingqing, Chu, Hongao, Feng, Peizhong
• Format: Article
• Language: English
• Subjects: Carbon; Ceramics; Characterization and Evaluation of Materials; Chemistry and Materials Science; Coatings; Composites; Glass; Materials Science; Molybdenum disilicides; Nanocrystals; Nanotechnology; Natural Materials; Oxidation; Oxygen; Partial pressure; Plasma sintering; Raw materials; Refractory materials; Research Article; Self propagating high temperature synthesis; Self-propagating synthesis; Silicon dioxide; Sintering (powder metallurgy); Spark plasma sintering; Structural Materials; Transition metal oxides; Zirconium compounds
• ISSN: 2226-4108; 2227-8508
• DOI: 10.1007/s40145-021-0485-y

To achieve high oxygen blocking structure of the ZrB 2 -MoSi 2 coating applied on carbon structural material, ZrB 2 -MoSi 2 coating was prepared by spark plasma sintering (SPS) method utilizing ZrB 2 -MoSi 2 composite powders synthesized by self-propagating high-temperature synthesis (SHS) technique as raw materials. The oxygen blocking mechanism of the ZrB 2 -MoSi 2 coatings at 1973 K was investigated. Compared with commercial powders, the coatings prepared by SHS powders exhibited superior density and inferior oxidation activity, which significantly heightened the structural oxygen blocking ability of the coatings in the active oxidation stage, thus characterizing higher oxidation protection efficiency. The rise of MoSi 2 content facilitated the dispersion of transition metal oxide nanocrystals (5–20 nm) in the SiO 2 glass layer and conduced to the increasing viscosity, thus strengthening the inerting impact of the compound glass layer in the inert oxidation stage. Nevertheless, the ZrB 2 -40 vol%MoSi 2 coating sample prepared by SHS powders presented the lowest oxygen permeability of 0.3% and carbon loss rate of 0.29×10 −6 g·cm −2 ·s −1 . Owing to the gradient oxygen partial pressure inside the coatings, the Si-depleted layer was developed under the compound glass layer, which brought about acute oxygen erosion.