니켈기 초내열합금(GTD-111)의 고온 용융염 부식에 미치는 영향

Abstract

Hot corrosion resistance of Ni-based superalloy GTD-111 was investigated as a function of experimental parameters including salt deposition method, cycle duration, and cleaning process in tests. Saturated solution of 75 wt.% Na2SO4 + 25 wt.% NaCl was deposited on the alloys. The samples were repetitively heated up to 700 ℃ for 2 ~ 15 h and cooled down. Weight change by hot corrosion was measured after cleaning in a boiling water and a ultrasonic agitator. The corrosion rate was evaluated from the weight loss of the samples and the structure and composition of corrosion products were analyzed by XRD and EPMA. The corrosion rate of GTD-111 was increased with or increase of the amount of deposited salt, heating duration, or frequency of cleaning.