The corrosion caused by air sediments comprising CaO-MgO-Al 2 O 3 -SiO 2 (CMAS) poses a notable challenge to thermal/environmental barrier coatings as engine service temperatures continue to rise. In this study, three types of Y 2 O 3 -SiO 2 binary compound ceramic bulks—Y 2 SiO 5 , Y 2 SiO 5 -Y 2 Si 2 O 7 and Y 2 Si 2 O 7 —with molar ratios of Y 2 O 3 :SiO 2 of 1:1, 1:1.5, and 1:2, respectively, were prepared and subjected to CMAS corrosion at 1250 °C and 1350 °C for durations ranging from 1 to 10 h. The corrosion products and cross-sectional morphologies of the samples were characterized using X-ray diffraction and scanning electron microscope. The results demonstrate that the material composition determines its CMAS corrosion behavior. Y 2 SiO 5 , with higher Y 2 O 3 content, consumes more CaO to form Ca 2 Y 8 (SiO 4 ) 6 O 2 , thereby reducing the CaO content and increasing the viscosity of the residual CMAS melt. This process inhibits further CMAS penetration. The findings highlight a novel strategy to improve CMAS corrosion resistance by modifying the CMAS composition and reducing its penetration capability.
The coupled factors of high temperature, high humidity, and high salinity in tropical marine atmospheres severely threaten the long-term service performance of power transmission and transformation infrastructure. This paper establishes an accelerated cyclic testing protocol (salt spray → drying → damp heat → drying) to evaluate performance and elucidate the dynamic corrosion failure mechanisms of the organic Zn14Al1.4 composite coating. By integrating multiphysical characterization techniques (SEM, EDS, XPS) with electrochemical analysis, this study for the first time elucidates the dynamic transformation of corrosion products: initially dominated by Zn(OH)2, progressing to complex passive phases such as Zn5(OH)8Cl2·H2O, Zn5(OH)6(CO3)2, and Zn6Al2(OH)16CO3in the mid-term, and ultimately dominated by Fe-based products (FeO, Fe2O3, Fe3O4, FeOOH) that drive interfacial failure. And a four-stage corrosion evolution model was defined: incubation period, accelerated degradation phase, substrate nucleation stage, and catastrophic failure phase. The investigation reveals a shift in the coating/substrate interface failure mechanism from purely physical barrier effects to electrochemical synergy, providing a theoretical framework for the optimized design and service-life prediction of anticorrosive coatings for transmission and transformation equipment in tropical environments.
危险品化学品经营许可证（带存储）