Abstract
Effect of heat treatment and ceramic coatings to HVOF (JP-5000) spray coatings for prevention of high temperature corrosion in waste incineration plants have been investigated by laboratory and field tests.
1) Alloy 625 spray coating layer by JP-5000 diffused to base metal by heat treatment. The layer indicated good high temperature corrosion resistance in compared with SUS347HTB and SUS310J1.
2) Ceramic (ZrO2-Y2O3/Al2O3) top coating on alloy 625 and CoNiCrAlY layer by JP-5000 is confirmed improve the quality of metallic layers and penetration restrain for corrosive matter into the coating layers at gas temperature of 950-1050°C in field test.
3) Diffusion between the metallic coating layers and base metal are observed by heat treatment in air in the metallic/ceramic duplex coating layers. Also, good corrosion resistance was observed at gas temperature of 550-620°C by field test in the ceramic coating layer.
4) Although there are some problems such as increased coating times and its cost, application of heat treatment and ceramic (ZrO2-Y2O3/Al2O3) double layers coating for metallic coating layer to prevention of high temperature corrosion in waste incineration plants are considered to be effective because of noticeable improvement effect for high temperature corrosion resistance.
