2005 Volume 54 Issue 5 Pages 218-224
The effect of alloying elements on the corrosion resistance of Ni-base cast alloys in chlorine-containing high temperature environment was investigated. Previous works have shown that corrosion rate peak are emerged at around 900°C in chlorine-containing atmospheres and related to the behavior of the chloride inside the alloy. In this work, it was found that addition of Al to the alloys reduced the peak and improved corrosion resistance. The role of Al is considered the formation of Al2O3 scale and the prevention of Cl accumulation inside the alloy. It was also found that addition of Si to Al added-alloys improved corrosion resistance. Based on the obtained result in the laboratory test, base alloys (Ni-33Cr-15W-1Si-0.3C) and Al-added alloys (Ni-33Cr-10W-2Si-2Al-0.3C) were exposed in an actual incinerator at around 900°C for one year. The corrosion amount of the Al-added alloys was much smaller than that of the base alloys. The test proved that addition of Al is promising for practical applications.
