工艺参数对SiO2／S涂层形貌与结构的影响

Deposition and Microstructures of SiO_2/S Anti-Coking Coatings

为了抑制乙烯裂解炉管内表面结焦,采用常压化学气相沉积方法在HP40试样上制备了SiO2/S涂层。用SEM和Raman光谱研究了沉积温度、源物质分压以及气体流速对SiO2/S涂层形貌和结构的影响。结果表明随着沉积温度的增加,涂层组成粒子直径变化不大,粒子之间的结合更为致密,同时生成的三节环Si-O-Si结构逐渐增多,Si-O-S结构逐渐减少。气体流速与源物质分压对涂层粒子形貌的影响规律相似,随着各自参数的增加,涂层粒子逐渐增大,涂层更加致密。源物质分压和气体流速分别为40Pa和0.4m.s-1时,涂层中含有较多Si-O-S和三节环Si-O-Si结构。

The anti-coking and anti-carburizing Si02/S films were grown by chemical vapor deposition （CVD） at amospheric pressure on substrates of heat-resistant HP40 steel, widely used in ethylene crackers. The morphology of the SiO2/S coating was characterized with scanning electron microscopy （SEM） and Raman spectroscopy. The influence of various coating conditions, including the substrate temperature, gas flow rate and partial pressure of precursors, on microstructures of the coating was studied. The results show that the partial pressure of precursor and the gas flow rate strongly affect the stoichiometry and morphology of the coating. For example, at a partial pressure of 40Pa and a gas flow rate of 0.4m·s^ - 1, high densities of Si - O - S and Si - O - Si were obtained. Possible mechanisms were also tentatively discussed.