摘要
通过对纯镍在900℃熔融盐w(NaCl)=25%-w(Na_2SO_4)=75%和Na_2SO_4中进行恒温热腐蚀实验,研究了不同熔融盐成分对纯镍在恒温热腐蚀期间的腐蚀特征、行为和机理.结果表明:Ni在2种熔融盐腐蚀过程中无选择性和顺序性,不存在腐蚀孕育期,腐蚀产物均以NiO和Ni3S2为主,在w(NaCl)=25%-w(Na_2SO_4)=75%熔融盐中的腐蚀速率明显大于在Na_2SO_4熔融盐中.在Na_2SO_4熔融盐中,纯镍的氧化、硫化同时进行,热腐蚀形态表现为从表面氧化膜内侧向基体内部延伸的内氧化物与内硫化物分布;在w(NaCl)=25%-w(Na_2SO_4)=75%熔融盐中,是氧化、硫化和氯化三者相互作用增强的结果,氯和硫在热腐蚀过程中起着重要的作用.
The influence of molten salt composition on hot corrosion feature,behavior,and mechanism of pure nickel corroded in molten salts w(NaCl)=25%-w(Na_2SO_4)=75%and Na_2SO_4 at constant temperature of 900℃is investigated by means of hot-corrosion experiment on them in molten salt at constant temperature.Experimental result shows that there will be neither corrosion incubation period nor selectivity and ordering for Ni during the corrosion in both the salts,and the corrosion products will be mainly composed of NiO and Ni3 S2.Corrosion rate in w(NaCl)=25%-w(Na_2SO_4)=75%salt will be obviously larger than that in Na_2SO_4 salt.Simultaneous oxidation and sulfuration of pure nickel hot corroded in Na_2SO_4 salt will take place and its hot corrosion form will exhibit as the distribution of internal oxides and sulfides from inner side of surface oxide film extending to the substrate interior.In w(NaCl)=25%-w(Na_2SO_4)=75% salt,hot corrosion process will include sulfuration,oxidation,and chlorination with chlorine and sulfur playing an important role in the process of hot corrosion.
引文
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