| 摘要 |
PROBLEM TO BE SOLVED: To provide a corrosion resisting nitride film for providing a ferrous material with excellent wear resistance and corrosion resistance. SOLUTION: Nitriding treatment is applied to a ferrous material at a gaseous mixture of nitrogen and hydrogen of about 4Torr for 4hr, by which a corrosion resisting nitride film containing iron oxide and having 400-1,200HV hardness is formed to 5-500μm film thickness. In this corrosion resisting nitride film, the natural potential at the time of immersion in a 3% aqueous solution of NaNO3 (35 deg.C) is nobler than -100mV(vsSCE), and also the natural potential at the time of immersion in a 1% aqueous solution of NaCl (35 deg.C) is nobler than -200mV(vsSCE). Further, the pitting corrosion potential V'c100 at the time of immersion in a 3.5% aqueous solution of NaCl (30 deg.C) is nobler than -200mV(vsSCE). Moreover, the ratio of the integrated intensity of theγ-Fe4 N(111) peak in the biaxial X-ray diffraction measurement (Cu-Ka line) to the integrated intensity of theα-Fe(110) peak is regulated to >=0.1.
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