High-temperature oxidation and ablation behavior of plasma sprayed LaB6-MoSi2-TiB2 composite coating. (15th August 2018)

• Record Type: Journal Article
• Authors: Wang, Changcong; Li, Kezhi; He, Qinchuan; Huo, Caixia; Shi, Xiaohong
• Is Part Of: Materials & design. Volume 152(2018)
• Page Start: 40
• Page End: 53
• Publication Date: 2018-08-15
• Subjects: Composite coating -- Plasma spraying -- Oxidation -- Ablation -- Compound scale; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2018.04.059
• Languages: English
• ISSNs: 0264-1275

Abstract

Abstract: A combined heterogeneous coating composed of LaB6 -MoSi2 -TiB2 (LMT) outer layer and SiC inner layer was fabricated on carbon/carbon (C/C) composites using a two-step method. Among them, the SiC transition layer was in-situ synthesized by pack cementation (PC) in the first step, where-after supersonic atmospheric plasma spraying (SAPS) was devoted to deposit the LMT outer layer. The combined LMT/SiC coating revealed a representative microstructure with limited porosity and adhered well with the C/C substrate. Isothermal oxidation test demonstrated that the combined LMT/SiC coating displayed a better oxidation resistance than the MoSi2 /SiC coating without the addition of rare-earth La and alloying Ti elements at 1773 K. Oxyacetylene torch experiment showed that the combined LMT/SiC coating could efficiently protect the C/C composites withstand short-term ablation for 60 s. The good oxidation and ablation resistant properties of the combined LMT/SiC coating were ascribed to the integrity of LMT/SiC coating and superior protection of a glassy La-Si-O-B-Ti compound scale formation during oxidation and ablation. Graphical abstract: Unlabelled Image Highlights: Good adherence of LaB6 -MoSi2 -TiB2 coating ascribed mechanical bonding with interlocking. The incorporation of TiB2 improved oxidation and ablation resistance of LaB6 -MoSi2 coating. Selective oxidation of La, Ti and Si suppressed the occurrence of pest oxidation. The formation of La-Si-O-B-Ti compound scale ensured long-term stability of LaB6 -MoSi2 -TiB2 coating.