无机复合涂层对CB2铁素体耐热钢在650℃水蒸气中的防护

Protective Performance of a Novel Inorganic Composite Coatings on CB2 Ferritic Heat Resistant Steel at 650℃ in Oxygen Flow with Water Vapor

采用物理共混工艺制备无机硅酸盐复合涂层,研究其对ZG12Cr9Mo1Co1NiVNbNB(CB2)铁素体耐热钢在650℃水蒸气中氧化的防护。结果表明,CB2钢在650℃水蒸气中的氧化严重,氧化过程分段遵循抛物线规律,生成了双层非保护性Fe_(2)O_(3)氧化膜。涂装无机硅酸盐复合涂层使CB2钢的氧化速率显著降低,涂层还具有良好的抗热震性能。在涂层与基体钢的界面处生长一层厚度约2μm的富铬氧化层,使合金的抗氧化性能提高。

A novel inorganic silicate composite coating was prepared by physical blending process with potassium silicate of module 3.25 as binder,alpha alumina,copper chromium black and white mica as pigment,and proper amount curing agent.Then the oxidation behavior of the ZG12Cr9Mo1Co1NiVNbNB(CB2)ferritic heat resistant steel without and with the composite coating was comparatively investigated at 650℃ in atmosphere of oxygen flow with 20% water vapors.The results show that serious oxidation of CB2 steel occurred,which follows the parabolic law in different periods and resulted in the formation of a two-layered oxide scale of poorly protective Fe_(2)O_(3).The application of the composite coating could reduce markedly the oxidation rate of the CB2 steel,meanwhile the coating presented also excellent resistance to cyclically thermal shock.Furthermore,a thin and continuous Cr-rich oxide layer could be detected on the steel surface beneath the composite coating after the oxidation test,to which the enhancement of oxidation resistance of the coated CB2 steel may be ascribed.