Nippon Steel Corporation

Sintokogio, Ltd.

Nippon Micrometal Corporation

Nippon Steel & Sumikin Materials Co., Ltd.

Kazuto Kawakami

Koki Tanaka

Michio Kaneko

Hiroshi Kihira

Mitsuharu Yamagata

Yoichi Ikematsu

Yoichi Matsuzaki

Wataru Hisada

Suguru Suzuki

Tsutomu Sasaki

Makoto Okonogi

Masamoto Tanaka

Takahiko Kohtake

Takayuki Kobayashi

Masayoshi Fujishima

A steel contains, in a chemical composition, C, Si, Mn, and Al, and contains pearlite as a metallographic structure, and a value obtained by dividing an Mn content in a cementite in the pearlite in terms of at % by an Mn content in a ferrite in the pearlite in terms of at % is higher than 0 and equal to or lower than 5.0.

Steel for cold forging

A lead-free solder alloy exhibiting good performance in impact resistance and vibration resistance. Also provided are a solder ball using such a lead-free solder alloy, and an electronic member having a solder bump using such a lead-free alloy. Specifically, the lead-free solder alloy consists of 1.0 to 2.0% by mass of Ag, 0.3 to 1.0% by mass of Cu, 0.005 to 0.1% by mass of Ni and the balance including Sn and unavoidable impurities. In an Sn&#x2014;Ag&#x2014;Cu based solder joint portion on a Cu electrode, a CuSn intermetallic compound layer is formed directly on the Cu electrode, and then a CuSnintermetallic compound layer is formed thereon. A Cu atomic site in the CuSnintermetallic compound layer is replaced by Ni having a smaller atomic radius than Cu to thereby reduce strain in the CuSnintermetallic compound layer, thus enabling impact resistance and vibration resistance to be improved therein.

Lead-free solder alloy, solder ball and electronic member, and lead-free solder alloy, solder ball and electronic member for automobile-mounted electronic member

The present invention releases a method of producing a metal separator for a solid polymer fuel cell by stainless steel, titanium, or titanium alloy during which securing lower cost and mass producibility by using a material having a high workability to form a complicated shape by a high productivity, then using an inexpensive blast process to drive a conductive substance into the surface of the metal separator member, that is, provides a stainless steel, titanium, or titanium alloy solid polymer fuel cell separator comprised of stainless steel, titanium, or titanium alloy in the surface of which a low ion release conductive substance is buried, having an arithmetic mean roughness (Ra) of the separator surface of 0.5 to 5.0 &#x3bc;m, having a 10-point mean roughness (Rz) of 3 to 20 &#x3bc;m, having an average spacing of surface relief shapes (Sm) of 300 &#x3bc;m or less, having values of a warp rate and twist rate of a separator of 0.1 or less, and having a contact resistance value with respect to carbon paper of 15 m&#x3a9;cmor less at a surface pressure of 1 MPa.

Stainless steel, titanium, or titanium alloy solid polymer fuel cell separator and its method of production and method of evaluation of warp and twist of separator

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Futtsu, Japan

Kazuto Kawakami