Nisshin Steel Co., Ltd.

Other

Minoru Saito

Yasushi Fukui

Masanori Matsuno

Tadaaki Miono

Hiroshi Tanaka

Hideo Miyake

Masahiko Souda

Toshiharu Kittaka

Yoshikazu Morita

Yusuke Hirose

Yasumi Ariyoshi

Kazushi Sakamoto

Atsushi Ando

Kazuaki Chohata

Takeshi Nagatani

Kazuaki Hosomi

Katsuhiko Masaki

Toshiharu Kitsutaka

Yukihiro Morita

A separator for a low-temperature fuel cell comprises a stainless steel substrate S having a surface to which carbonaceous particles such as graphite particles GP or carbon black aggregates CA adhere with dotted distribution. The carbonaceous particles are preferably bonded through a diffusion layer DL to the surface of the substrate S. The carbonaceous particle-dispersed layer may be a plating layer in which graphite particles GP or carbon black aggregates CA are dispersed or formed by thermal decomposition of organic components in a carbonaceous particle-dispersed paint applied to the surface of the substrate S. Since carbonaceous particles free from oxide films adhere to the surface of the acid-resistant stainless steel substrate S, contact resistance of the separator is sufficiently low. Consequently, a power generator having a plurality of fuel cells laminated together exhibits high power-generating efficiency with less heat loss caused by a Joule heat.

Separator for low temperature type fuel cell and method of production thereof

A metal vapor 12 passing through a guide duct 13 from a vapor source 10 to a steel strip 1 is sampled through a takeoff pipe 14 to a measuring chamber 15. The metal vapor is irradiated with a measuring beam 20 in the chamber 15, to detect the absorbance of luminous energy in the metal vapor. The detected value of absorbance is used for the quantitative calculation of the metal vapor 12 passing through the guide duct 13, and the opening ratio of a shutter 17 provided in the guide duct 13 is adjusted on the basis of the calculation result so as to control the flow amount of the metal vapor 12 passing through the guide duct 13. In the case where a large amount of the metal vapor 12 passes through the guide duct 13, the amount of the metal vapor 12 reaching the measuring beam 20 is reduced by partially discharging the metal vapor 12 from the measuring chamber 15. Since the deposition amount of a plating metal is directly controlled in response to the amount of the metal vapor 2 passing through the guide duct 13, the amount of a deposited plating layer is controlled with high accuracy and with a quick response time in a continuous vapor deposition coating line.

Atomic absorption analysis for measuring and controlling the amount of a

A Zn-Mg binary coating layer formed on a steel sheet has the tri-layered structure that the first sublayer composed of a Zn-Mg alloy having Mg concentration of 0.5 wt. % or less, the second sublayer composed of a Zn-Mg alloy having Mg concentration of 7 wt. % or more and the third sublayer composed of a Zn-Mg alloy having Mg concentration of 0.5 wt. % or less are successively laminated. The coating layer may have the penta-layered structure wherein sublayers composed of a Zn-Mg alloy having Mg concentration of 2-7 wt. % are additionally interposed between the high-Mg and low-Mg sublayers. A Zn-Fe or Zn-Fe-Mg alloy layer may be formed at the boundary between the substrate steel and the coating layer. The adhesion ratio of the first sublayer to the top sublayer is preferably 1.2 or more, while the high-Mg sublayer is preferably conditioned to the mixed structure of a Zn.sub.2 Mg phase with a Mg-dissolved Zn phase. Due to the specified lamellar structure, the intrinsic properties of the high-Mg sublayer is sufficiently exhibited, and the secondary paint adhesiveness of the coating layer is excellent. Consequently, the coated steel sheet is useful as structural members or parts exposed to a severe corrosive atmosphere in various industrial fields.

Steel sheet coated with Zn-Mg binary coating layer excellent in

A Mg source 3 is received in a vessel 1 having an opening 8, and the vessel 1 is heated at 670.degree. C. or higher to effuse Mg vapor through the opening 8. Since the vessel 1 is filled with Mg vapor, Mg is evaporated from molten state under stable condition without fluctuations in evaporation speed. The Mg vapor is effectively consumed for vapor deposition. A reflector plate may be provided at the outlet of the opening 8, or a duct for introducing Mg vapor from the vessel to the surface of a substrate sheet may be provided. In order to evaporate Mg from stabilized molten state, operational conditions are preferably determined so as to satisfy the relationships of W.sub.1 /W.sub.2 &lt;0.6.times.(P.sub.Mg /V.sup.3) and W.sub.1 /W.sub.2 &lt;0.04.times.P.sub.Mg, wherein W.sub.1 represents the area (mm.sup.2) of the opening 8, W.sub.2 represents the evaporation surface area (mm.sup.2) of the Mg source 3, P.sub.Mg represents Mg vapor pressure (torr.) and V represents the degree of vacuum.

Formation of magnesium vapor with high evaporation speed

A Zn--Mg binary coating layer formed on a steel sheet has the tri-layered structure that the first sublayer composed of a Zn--Mg alloy having Mg concentration of 0.5 wt. % or less, the second sublayer composed of a Zn--Mg alloy having Mg concentration of 7 wt. % or more and the third sublayer composed of a Zn--Mg alloy having Mg concentration of 0.5 wt. % or less are successively laminated. The coating layer may have the penta-layered structure wherein sublayers composed of a Zn--Mg alloy having Mg concentration of 2-7 wt. % are additionally interposed between the high-Mg and low-Mg sublayers. A Zn--Fe or Zn--Fe--Mg alloy layer may be formed at the boundary between the substrate steel and the coating layer. The adhesion ratio of the first sublayer to the top sublayer is preferably 1.2 or more, while the high-Mg sublayer is preferably conditioned to the mixed structure of a Zn.sub.2 Mg phase with a Mg-dissolved Zn phase. Due to the specified lamellar structure, the intrinsic properties of the high-Mg sublayer is sufficiently exhibited, and the secondary paint adhesiveness of the coating layer is excellent. Consequently, the coated steel sheet is useful as structural members or parts exposed to a severe corrosive atmosphere in various industrial fields.

Steel sheet coated witn Zn-Mg binary coating layer excellent in

An iron-based heat-generating material excellent in oxidation resistance at an elevated temperature which comprises an iron-based alloy capable of generating heat by passing electricity therethrough and a coating of aluminum and oxygen formed on the surface of the alloy, the amount of the oxygen in the coating is less than the stoichiometric amount of oxygen in Al.sub.2 O.sub.3. The material can be prepared by vacuum evaporation of Al onto the surface of the iron-based alloy wherein an oxygen partial pressure in a vacuum gaseous atmosphere for the vacuum evaporation is adjusted so that there is formed on the surface of the alloy a coating consisting of aluminum and oxygen, the amount of the oxygen in the coating being less than the stoichiometric amount of oxygen in Al.sub.2 O.sub.3. When the material is heated in ambient or oxidizing atmosphere, an outermost layer of the coating is rapidly converted to Al.sub.2 O.sub.3.

Iron-based material having excellent oxidation resistance at elevated

Vapor deposition for formation of plating layer

The surface of a stainless steel sheet before Fe-coating and the surface of the same stainless steel sheet after Fe-coating are analyzed by X-ray fluorescent analysis to determine the ratio of a fluorescent X-ray intensity I.sub.Cr b ascribable to CF to a fluorescent X-ray intensity I.sub.Fe b ascribable to Fe before Fe-coating, I.sub.Cr b/I.sub.Fe b, and the ratio of a fluorescent X-ray intensity I.sub.Cr a ascribable to Cr to a fluorescent X-ray intensity I.sub.Fe a ascribable to Fe after Fe-coating, I.sub.Cr a/I.sub.Fe a, and the resulting values are substituted in the following equation to calculate an Fe coating weight W (g/m.sup.2).

Method for measuring Fe coating weight of Fe-coated stainless steel sheet

A system for making an on-line determination of the degree of alloying in galvannealed steel sheets are provided, which includes an X-ray tube for generating X-ray, detectors for detecting the X-ray diffraction intensity of the .zeta. phase and .GAMMA. phase of Fe--Zn intermetallic compounds phases of the galvannealed steel sheet and a detector for detecting the background intensity, all of the detectors being located same plane on the surface of the galvannealed steel sheets, and further includes an arithmetic unit for receiving the outputs of the detectors to compute the X-ray diffraction intensities. Preferably, this system includes a detector for detecting the X-ray diffraction intensity of the .delta..sub.1 phase.

System for making an on-line determination of degree of alloying in

A method for estimating the press formability of galvannealed steel sheets provided, wherein: the values found by: ##EQU1## wherein I(.gamma.)=the total X-ray diffraction intensity of the .gamma. phase,

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Sakai, Japan

Minoru Saito