Plasma-assisted particle deposition manufacturing: Multi-functional integrated superhigh temperature thermal protection coating on niobium alloy

Multi-functional integrated thermal protection coating is a promising approach for the high-temperature protection of niobium alloy while facing multiple extremely harsh environments, while hard to avoid the complex/multi-step preparation process. Particularly, a simultaneous demonstration of multi-functional features is still challenging. Herein, a novel HfC-HfO2-MoSi2-Yb2O3 multi-functional layer has been fabricated on the NbSi2 layer surface via plasma-assisted particle deposition manufacturing, endowing the modified silicide-based multilayer composite coating with multiple thermal protective characteristics. The composite coating shows excellent hot corrosion resistance with a corrosion gain of 3.56 mg cm−2 after 200 h, the intact coating structure after three thermal cycles of fast rise and fall from 25 °C–1800 °C, and a high thermal emissivity of above 0.9, as well as the good high-temperature oxidation resistance and ablation resistance demonstrated in our previous study. The superior multiple thermal protective characteristics are attributed to the synergistic effects of multi-functional particles. HfC particle provides the anti-ablation skeleton, MoSi2 particle provides more SiO2 glass phase and seals defects, Yb2O3 particle acts as the stabilizer of glass network, and matching vibration absorption of multiphase/multi-chemical bonds endow the high emissivity of coating. Our work paves the new way and provides an inexpensive and environmentally friendly approach for the development of a new class of multi-functional integrated thermal protection materials.