Alloy materials can be severely degraded by corrosive gases and coal ash in service of coal power plants at high temperature. To better understand alloy corrosion in coal power plants, it is necessary to study the effect of each constituent from coal combustion on alloy corrosion. Chlorine-containing compounds in coal are corrosion-accelerating agents. The concentration of chlorine increases a lot in the gas environment of oxy-fuel combustion due to the absence of airborne nitrogen gas acting as a diluent. The role of chlorine in ash corrosion is investigated in simulated oxy-fuel environments. Long time tests over 3000 h were performed on various alloys at 750 °C. The degradation depth, weight change, and microstructural characteristics of oxide scales on Ni-based alloys are reported after exposure at 750 °C in an oxy-fuel combustion environment for over 3000 h. Synchrotron nanobeam X-ray analysis was performed to evaluate the phase and chemical composition of the oxide layers on the alloy surface. Nanobeam X-ray and SEM analyses indicate that chlorine can modify the diffusion mechanism near the alloy surface and, thereby, increase the corrosion rate.

中文翻译：

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模拟氧-燃料环境中灰中氯对镍基合金腐蚀性能的影响

高温下，发电厂使用的腐蚀性气体和煤灰会严重降解合金材料。为了更好地了解燃煤电厂的合金腐蚀，有必要研究燃煤中每种成分对合金腐蚀的影响。煤中的含氯化合物是腐蚀促进剂。由于不存在用作稀释剂的空气传播的氮气，在含氧燃料燃烧的气体环境中，氯的浓度增加很多。在模拟的含氧燃料环境中，研究了氯在灰分腐蚀中的作用。在750°C下对各种合金进行了3000个小时以上的长时间测试。降解深度，重量变化，据报道，在750°C的氧气-燃料燃烧环境中暴露超过3000小时后，Ni基合金上的氧化皮的微观结构和微结构特征得到了报道。进行了同步加速器纳米束X射线分析，以评估合金表面氧化物层的相和化学组成。纳米束X射线和SEM分析表明，氯可以改变合金表面附近的扩散机理，从而提高腐蚀速率。