石炭ガス化雰囲気における金属材料の高温腐食

抄録

The corrosion resistance of commercial grades stainless steels, Fe-base, Ni-base, and Co-base alloys and that of the pack coated alloys with Cr, Al, or Si were investigated in a simulated coal gasification atmosphere in the temperature range of 200 to 850°C for 100 to 500 hours. Fe- and Co-base alloys and high Cr (>20%) stainless steels exhibited good corrosion resistance to sulfur attack. Ni-base alloys were rapidly sulfurized above 600°C. Pack aluminizing of alloys with high Cr was the most effective in improving the resistance to sulfidation attack comparing with pack chromizing and pack siliconizing. In order to clarify the effects of alloying elements to sulfur attack, additional experimental heats in which the content of Cr, Ni, Co and Al was individually changed were examined in the same corrosive condition. Addition of Cr, Co or Al to Fe-Cr alloys was effective against sulfidation. It was observed that addition of 2 to 3% of aluminum to Fe-Cr or Fe-Cr-Ni alloys promoted the formation of protective oxide scale. A discussion was made on the effect of these alloying elements in Fe-base alloys on the corrosion behavior in the coal gasification atmosphere.