In-situ synthesis, microstructure, and properties of NbB2-NbC-Al2O3 composite coatings by plasma spraying

Abstract The high melting point and strong chemical bonding of NbB 2 pose a great challenge to the preparation high-density nanostructured composite coating. Herein, we report novel, simple, efficient method fabricate in-situ -NbC-Al O 3 coating by plasma spraying Nb 5 -B 4 C-Al powder, aiming at realizing higher densification ultra-fine microstructure properties were studied comparatively with ex-situ (plasma powder). reaction mechanism powder in jet was analyzed detail. results showed that presented lower porosity superior performance including microhardness, toughness wear resistance compared sprayed other boride coatings. Densification attributed low exothermic effect reaction. ascribed density improvement strengthening toughening nanosized phases. path could be expressed as: + Al → , B C NbC.