ABSTRACT

High-temperature corrosion of coal-fired boiler parts such as water walls and superheated tubes poses a serious threat to the efficiency of the thermal power plant. To overcome this, numbers of corrosion control techniques are commonly employed. But, a dense and defect-free coating deposited by the thermal spray technique has shown promising result to combat hot corrosion. Although open or closed porosity in distinct thermal spray coatings can originate from distinct factors such as partial or totally un-molten particles, inadequate flow or fragmentation of the molten particle at impact, non-optimal spray angle and entrapped gas. But, this can still only be prevented by coating post-treatment. Hence, in this paper, authors have reviewed the performance of distinct coatings deposited by diverse thermal spray processes. Then, the effect of distinct process parameters and heat treatments on microstructure and mechanical properties of coatings is described. Finally, the best coatings are suggested to combat maximum hot corrosion of boiler tubes.

摘要

水冷壁、过热管等燃煤锅炉部件的高温腐蚀对热电厂的效率构成严重威胁。为了克服这一点，通常采用多种腐蚀控制技术。但是，通过热喷涂技术沉积的致密且无缺陷的涂层已显示出对抗热腐蚀的有希望的结果。尽管不同热喷涂涂层中的开孔或闭孔可能源于不同的因素，例如部分或完全未熔化的颗粒、流动不充分或熔融颗粒在撞击时破碎、非最佳喷射角度和夹带气体。但是，这仍然只能通过涂层后处理来防止。因此，在本文中，作者回顾了通过不同热喷涂工艺沉积的不同涂层的性能。然后，描述了不同的工艺参数和热处理对涂层微观结构和机械性能的影响。最后，建议最好的涂层来对抗锅炉管的最大热腐蚀。