Investigation of Ni-Based Brush Seal Coatings With Self-Lubricating Property at Elevated Temperature
ZHANG Tiantian1,2, HUANG Chuanbing1, LAN Hao1, FANG Shige1, ZHANG Weigang1
( 1. Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China;
2. University of Chinese Academy of Sciences, Beijing 100049, China)
In order to meet the requirement of self-lubricating and wear resistant properties of brush seal coatings for advanced aeroengines, two kinds of novel composite coatings, NiCoCrAlY-Cr2O3 and NiCoCrAlY-Cr2O3-AgMo, were prepared with plasma spray technology. Microstructures, phase compositions, mechanical properties, friction and wear performances of the above coatings were characterized and analyzed with scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy and CSM high-temperature tribometer. The results show that both coatings exhibit very low porosity, high microhardness and tensile strength. The wear rates of two coatings are all at the order of 10-5 mm3· N-1·m-1, indicating the excellent wear resistance. The friction coefficient of the coating NiCoCrAlY-Cr2O3 decreases with temperature increasing, which shows a minimum value of 0.3 at 800℃ . NiCoCrAlY-Cr2O3-AgMo coating keeps a lower friction coefficient of about 0.23 from 400℃ to 800℃. Investigation of friction and wear mechanisms show that at 400℃, a lubricating film containing Ag is formed between the coating and the counterpart, while Ag2MoO4 formed above 600℃ effectively reduces the friction and wear at high temperatures.
2017, 
