范瑞麟
中国腐蚀与防护学报
研究了K3合金上NiCrAlY-ZrO_2·8％Y_2O_3涂层在热腐蚀条件下的破坏行为。熔盐沿陶瓷层晶界向内渗透导致底层的腐蚀,以及Y_2O_3的酸性溶解导致ZrO_2由C相向M相的转变是热障涂层热腐蚀破坏的主要原因。某些工艺因素导致涂层破坏或不稳定会造成涂层过早地灾难性破坏。
关键词:
热障
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Coating
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Hot corrosion
Enze Liuy Zhi Zheng Xiurong Guan Jian Tong Likui Ning Yongsi Yu
材料科学技术（英文）
DZ68 alloy is a new Ni-base directionally solidified superalloy for the blade of advanced turbine engine with high ratio of thrust-mass. In order to investigate the influence of pre-oxidation on the hot corrosion resistance of DZ68 alloy, pre-oxidation treatment was conducted at 950°C in air for 20 h. A mixture of 75% Na2SO4+25% NaCl (in mass fraction) was used for hot corrosion study at 900°C. The microstructure of specimens was investigated by using a scanning electron microscope (SEM) equipped with an energy dispersive spectroscopy (EDS). The compositions of the corroded specimens were determined by X-ray diffraction (XRD). After preoxidation at 950°C in air for 20 h, a protective scale consisting of Cr2O3, Al2O3, NiO, NiCr2O4, and Ni2Ti4O formed on the DZ68 superalloy surface. The pre-oxidation treatment improved the initial incubation stage of
the alloy in the mixture of 75% Na2SO4+25% NaCl melts at 900°C. The oxide layer degraded gradually with increasing the time of hot corrosion. Once the oxide layer was damaged, the corrosion rate would increase rapidly, accompanied by obvious spallation of the corrosion products. At 900 °C, the pre-oxidation treatment could not inhibit the accelerated hot corrosion of DZ68 in the mixture of 75% Na2SO4+25% NaCl melts, with a high corrosion rate.
关键词:
DZ68 superalloy
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