Preparation and high‐temperature oxidation resistance of multilayer MoSi <sub>2</sub> /MoB coating by spent MoSi <sub>2</sub> ‐based materials
Lu Zhu, Xiaohong Wang, Xuanru Ren, Xueqin Kang, Farid Akhtar, Peizhong Feng
Abstract
Abstract Spent MoSi 2 and MoB were used as raw materials to prepare multilayer MoSi 2 /MoB coating on molybdenum by the two‐step method of slurry deposition and spark plasma sintering. The results showed dense MoSi 2 /MoB coating after sintering while penetrated cracks appeared in MoSi 2 coating due to coefficient of thermal expansion mismatch between the Mo substrate and coating. After the sintering of MoSi 2 /MoB coatings, MoB and Mo 2 B diffusion layers were formed between MoB transition layer and Mo substrate without defects, exhibiting good metallurgical bonding. The high‐temperature oxidation behavior of coatings (1500°C) was also explored. After oxidation of 50 h at 1500°C, lowest mass gain (0.035 mg/cm 2 ) was obtained for MoSi 2 /MoB coating, and the oxide scale was dense and complete without voids, making the oxygen diffusion at elevated temperature inhibited. Compared with MoSi 2 coating under the same oxidation conditions, relatively thinner silica oxide scale was acquired by MoSi 2 /MoB coating because of the reduction of cracks, and the multilayer coating exhibits better anti‐oxidation properties at high temperature.