Development of High corrosion - resistant Materials for Advanced Waste Incineration Plants

点击翻译按钮获取中文摘要

The object of this study was the development of high corrosion-resistant materials for the heat exchange of the exhaust gas in the advanced waste incineration plants. As the metallic materials, which can be resistant to the exhaust gas environment, are limited to Ni-base alloys, pure Ni, binary Ni-Cr alloys, and ternary Ni-Cr alloys containing Mo or Si were prepared as the sample materials. The hot corrosion behavior of these materials in the exhaust gas-imitative environment was investigated. Finally, the chemical composition of alloy having high corrosion-resistant was showed. The obtained results were as follows:1. The coating of molten Na_2SO_4-NaCI-KCI on the specimen extremely increased the mass gain due to oxidation of pure Ni, Ni-Cr and Ni-Cr-(Si, Mo) alloy.2. The addition of trace amount of HCI into the oxygen atmosphere at high temperature of 1173 K inhibited the oxidation of pure Ni, while that accelerated the oxidation of Ni-Cr alloy.3. The addition of chromium into nickel decreased the mass gain due to oxidation under the coating of molten salt on the specimen in oxygen, oxygen containing HCI and oxygen containing HCI and water vapor. For this case, the formation of a continuous and dense scale consisting of Cr_2O_3 was observed.4. The addition of silicon or molybdenum into Ni-10mass% Cr alloy decreased the mass gain due to oxidation of the alloys under the coating of molten salt on the specimen in oxygen containing HCI atmosphere. For the case, the formation of a dense layer consisting of Cr_2O_3 at the interior side of the scale was observed.Consequently, it was found from the above results that the binary Ni-Cr alloys containing high amount of chromium and the ternary Ni-Cr-(Mo, Si) alloys was suitable as the high corrosion-resistant material for the heat exchange of the exhaust gas in the advanced waste incineration plants.