Nippon Steel Corporation

Nippon Steel Sumitomo Metal Corporation

Mitsuyuki Hasegawa

Michio Kaneko

Kiyonori Tokuno

Kazuo Yamagishi

Takao Wada

Mitsuru Nakayama

The titanium material includes a titanium oxide layer formed on a surface of titanium being a base material, the titanium oxide layer having a thickness measured by a glow discharge spectrometry of 60 to 300 nm, wherein: the titanium oxide layer contains 0.5 to 7.0 at % of nitrogen, and an arithmetic mean roughness Ra of a surface thereof is 2.0 to 4.0 &#x3bc;m; and a power spectrum of a surface roughness of the titanium material has a peak of an amplitude height of 0.005 to 0.020 &#x3bc;m in a range of a wavelength of 1.1 to 2.5 &#x3bc;m and has a peak of an amplitude height of 0.0010 to 0.0030 &#x3bc;m in a range of a wavelength of 0.80 to 0.98 &#x3bc;m. An L*a*b* color space may be L*: 30 to 40, a*: 2.0 to 9.0, and b*: &#x2212;7.0 to 18.0.

Titanium material

The present invention provides colored pure titanium or titanium alloy having low susceptibility to discoloration in an atmospheric environment exhibiting a superior resistance to discoloration even when the titanium is used in an environment of harsh acid rain such as a roof or wall material and free from deterioration of the aesthetic appearance over a long period of time, that is, colored pure titanium obtained by the anodic oxidation method, that is, colored pure titanium or titanium alloy having low susceptibility to discoloration in an atmospheric environment characterized by having an average phosphorus content in a range of 40 nm from a surface of a titanium oxide layer formed on the titanium surface of 5.5 atomic % or less and by having an average carbon concentration in a range of a depth of 100 nm from the titanium surface of 3 to 15 atomic %.

Colored pure titanium or titanium alloy having low susceptibility to discoloration in atmospheric environment

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Tsubame, Japan

Mitsuyuki Hasegawa