光电化学法研究镍基合金在288℃高温水中生成氧化膜的半导体性质

PHOTOELECTROCHEMICAL STUDY ON SEMICONDUCTOR PROPERTIES OF Ni-BASED ALLOYS OXIDE FILMS FORMED IN 288 C HIGH TEMPERATURE WATER

采用光电化学法研究了Incoloy800HT和Inconel600镍基合金在288℃高温水中形成的氧化膜的半导体性质.组成镍合金氧化膜的物相为Ni的氢氧化物或镍铁氧化物、Cr_2O_3和Fe_xNi_(1-x)Cr_2O_4,它们的特征带隙宽度分别为2.3,2.9/3.5和4.1 4.3 eV.在400 mV至+400 mV范围内,Incoloy800HT合金表面氧化膜的光电化学响应表现为n型半导体性质,Inconel600合金表面氧化膜的光电化学响应表现为n/p型半导体性质,同时,在半导体性质从n型转变为P型的临界电压下,光电化学响应相角发生180°转变.

The oxide films formed on Ni-based alloys in high temperature water with semiconductor properties were investigated by photoelectrochemical responses.Two Ni-based alloys（Incoloy 800HT and Inconel600） were corroded at 288℃for 100 h in water,and four contributions from the photocurrent are obtained by photoelectrochemical responses.Band gap energy of 2.3 eV is attributed to the presence of nickel hydroxide or nickel-ferrite oxide.Band gap energy of 2.9 and 3.5 eV are attributed to Cr_2O_3 and band gap energy in the range of 4.1-4.3 eV is attributed to the spinel phase Fe_xNi_（1-x）Cr_2O_4.In the photoelectrochemical responses in function of the applied potential tests,the oxide films on Incoloy800HT alloy indicate n type semiconductor in the potential range from -400 mV to ＋400 mV,and the oxide films on Inconel600 alloy indicate n/p type semiconductor.In addition, the dephasing angle of the photoelectrochemical responses has a 180°evolution at the potential where the semiconductor of oxide film turns from n to p type.