传热管用Incoloy800H合金在模拟石墨粉尘环境中的碳化行为研究

Carbonization Corrosion Behavior of Incoloy800H Alloy Used for Heat Transfer Tube in a Simulated Graphite Dust Environment

利用透射电子显微镜(TEM)、扫描电子显微镜(SEM)以及X射线衍射仪(XRD)等手段对Incoloy800H合金在650 oC饱和石墨粉尘环境中的碳化行为及其机制开展了研究。结果表明:Incoloy800H合金的碳化腐蚀深度曲线遵循抛物线规律,腐蚀速率常数为0.013μm/s1/2,腐蚀产物层厚度随腐蚀时间的延长而增加;碳化3000 h后,合金表面腐蚀产物层主要以尖晶石相MnCr_(2)O_(4)和碳化物(CrAlMn)xCy为主,碳化层内颗粒状腐蚀产物为MnCr_(2)O_(4)、M23C6以及Al_(2)O_(3),且主要沿晶界分布;晶界碳化-氧化是导致合金腐蚀进程加剧的关键因素。

The carbonization corrosion behavior of Incoloy800H alloy was studied in a saturated graphite dust environment at 650 ℃ by means of transmission electron microscope, scanning electron microscope and X-ray diffractometer. The results show that the carbonization corrosion depth versus time curve of Incoloy 800H alloy followed parabolic law, and the rate constant of carbonization corrosion is 0.013 μm/s1/2. The thickness of corrosion product layer increased with the prolonging of corrosion time. After corrosion for 3000 h, the corrosion products on Incoloy800H alloy surface composed mainly of MnCr_(2)O_(4)spinel and(CrAlMn)xCycarbide, while the granular products in the internal carbonization zone was confirmed as MnCr_(2)O_(4), M23C6and Al_(2)O_(3), distributing along the grainboundaries.The key factors, which aggravate the corrosion process of Incoloy800H alloy, was the carbonization-oxidation of grain boundaries.