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Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements thermiques, Heat treatment, Traitements thermochimiques et traitements par diffusion, Thermochemical treatment and diffusion treatment, Acier, Steel, Acero, Aluminisation, Aluminizing, Aluminizacion, Aluminieren, Composé intermétallique, Intermetallic compound, Compuesto intermetálico, Intermetallische Verbindung, Diffraction RX, X ray diffraction, Difracción RX, Roentgenbeugung, Diffusion(transport), Diffusion, Dureté, Hardness, Dureza, Haerte, Dépôt métal, Metal deposition, Deposición metal, Metallbeschichten, Etude expérimentale, Experimental study, Estudio experimental, Experimentelle Untersuchung, Feuille métallique, Metal foil, Hoja metálica, Blattmetall, Microstructure, Microestructura, Mikrogefuege, Revêtement, Coatings, Revestimiento, Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Traitement thermochimique, Thermochemical treatment, Tratamiento termoquímico, Thermochemische Behandlung, Usure abrasive, Abrasive wear, Desgaste abrasivo, and Abrasivverschleiss

To obtain the ductile and corrosive coating treatment for steel, the aluminizing treatments using aluminum foil on mild steel surface were performed at diffusion temperature from 700 to 1000°C. The foil aluminized steels had less voids in diffusion layers, than the hot-dip aluminized steels. The foil aluminized steels at diffusion temperature not higher than 800°C had a thinner brittle layer of aluminum rich intermetallic Fe2Al5, and that at diffusion temperature not lower than 900°C had thicker layers of iron rich intermetallics such as FeAl and Fe3Al. It was found that the three body abrasive wear rates of aluminized steels with FeAl and Fe2Al that diffused at not lower than 900°C against free SiC grains were smaller wear rate than those of the steels diffused at higher than 800°C.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Corrosion, Mécanismes fondamentaux et formes de la corrosion, Corrosion mechanisms, Acier galvanisé, Galvanized steel, Acero galvanizado, Couche mince, Thin film, Capa fina, Duennschicht, Couche protectrice, Protective layer, Capa protectora, Schutzschicht, Etude expérimentale, Experimental study, Estudio experimental, Experimentelle Untersuchung, Ferrites, Ferritas, Mécanisme corrosion, Corrosion mechanism, Mecanismo corrosión, Korrosionsmechanismus, Produit corrosion, Corrosion product, Producto corrosión, Korrosionsprodukt, Protection corrosion, Corrosion protection, Protección corrosión, Korrosionsschutz, Revêtement protecteur, Protective coatings, Revestimiento protector, Schutzueberzug, Solubilité, Solubility, Solubilidad, Loeslichkeit, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Vitesse corrosion, Corrosion rate, Velocidad corrosión, Korrosionsgeschwindigkeit, Zinc oxyde, Zinc oxide, Zinc óxido, and Zinkoxid

Galvanized steels are used extensively in atmospheric environments because of their high resistance to corrosion as well as their low cost of production. The corrosion resistance arises from the slow corrosion rate of the zinc layer that covers the steel (coating and shielding effect) and the low corrosion potential of zinc which keeps the steel under a reducing condition as long as zinc remains (sacrifice effect). However, detailed examination of the corrosion processes has shown that galvanized steels exhibit some corrosion resistance after the disappearance of metal zinc by corrosion. This effect has been ascribed to a protective nature of corrosion products from the zinc layer. It is important to establish the protective components of corrosion products for the elucidation of corrosion mechanisms and for the development and improvement of corrosion protection technologies. In this investigation, zinc oxide, zinc carbonate, basic zinc carbonate, and zinc ferrite were chosen as model corrosion products, it was noted that protective films must have very low solubilities and very low dissolution rates for them to persist, and their dissolution properties were examined by solubility calculations. The solubilities of zinc oxide, zinc carbonate, and basic zinc carbonate are similar and very large, indicating that these would be dissolved away in atmospheric environments. A further corrosion product, zinc ferrite, is not a major component, but can be formed as a thin layer by the corrosion of the zinc-steel alloy phase. The solubility product of zinc ferrite was estimated from thermodynamic data and its solubility was calculated. The solubility is very small and it can be concluded that zinc ferrite is the most likely protective film component among the zinc compounds described above.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Dépôt de métaux et d'alliages, Metallic coatings, Alliage base fer, Iron base alloys, Alliage binaire, Binary alloy, Aleación binaria, Aluminium alliage, Aluminium alloy, Aluminio aleación, Aluminiumlegierung, Couple diffusion, Diffusion pair, Par difusión, Diffusionspaar, Diffusion(transport), Diffusion, Dépôt métal, Metal deposition, Deposición metal, Metallbeschichten, Etude expérimentale, Experimental study, Estudio experimental, Experimentelle Untersuchung, Microscopie électronique balayage, Scanning electron microscopy, Microscopía electrónica barrido, Rasterelektronenmikroskopie, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Zinc alliage, Zinc alloy, Zinc aleación, Zinklegierung, Zingage immersion, Hot dip galvanizing, Galvanización con cinc sumergido, Feuerverzinken, Zingage, Zinc coating, Galvanización con cinc, and Verzinken

Synopsis : Fe/FeAl/Zn diffusion couples having a thin Fe-Al alloy layer composed of Fe2Al5, FeAl2 and a phases between Fe and Zn specimens were annealed at 673K for various time. Formation and growth kinetics of Fe-Zn alloy layer were investigated. ζ(FeZn13) phase formed between Zn specimen and the Fe-Al alloy layer after a certain incubation period, the length of which increased with increasing thickness of the Fe-Al alloy layer. The Fe-Al alloy layer was consumed and penetrated by ζ phase and then δ1(FeZn7) phase appeared between ζ phase and Fe specimen after disappearance of the Fe-Al alloy layer. It appears that Fe-Zn alloy layer is formed by reaction of Zn atoms with Fe atoms supplied through the Fe-Al alloy layer from Fe specimen.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Dépôt de métaux et d'alliages, Metallic coatings, Acier, Steel, Acero, Couche mince, Thin film, Capa fina, Duennschicht, Dépôt métal, Metal deposition, Deposición metal, Metallbeschichten, Etude expérimentale, Experimental study, Estudio experimental, Experimentelle Untersuchung, Microstructure, Microestructura, Mikrogefuege, Revêtement, Coatings, Revestimiento, Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Zinc, Zink, Zingage, Zinc coating, Galvanización con cinc, and Verzinken

The visual appearance, press formability and the corrosion resistance of electrogalvanized steel sheets change depending on the morphology of deposited Zn. In this paper, the effects of plating factors such as the surface condition of steel substrate, electrolysis factors and the bath condition on the morphology of deposited Zn were systematically discussed both from a crystallographic viewpoint of the epitaxy between Zn/steel and from an electrochemical viewpoint of the overpotential for Zn deposition. The crystal orientation index of Zn basal plane and the crystal size of Zn are decreased with increasing the overpotential for Zn deposition. They are also decreased with decreasing the epitaxy between Zn/steel even when the overpotential is kept constant. When the overpotential for Zn deposition is increased, the surface roughness of deposited Zn becomes larger because of an increase in the inclination of Zn basal plane to steel substrate. When the epitaxy between Zn/steel is decreased without changing the overpotential, the surface roughness becomes smaller because of the decrease in crystal size of Zn although the inclination of Zn basal plane is somewhat increased.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Corrosion, Protection contre la corrosion, Corrosion prevention, Acier faiblement allié, Low alloy steel, Acero débilmente aliado, Niedriglegierter Stahl, Acier ressort, Spring steel, Acero resorte, Federstahl, Acier, Steel, Acero, Automobile, Motor car, Automóvil, Kraftwagen, Corrosion piqûre, Pitting corrosion, Corrosión superficial, Lochkorrosion, Elément alliage, Alloying element, Elemento aleación, Legierungselement, Etude expérimentale, Experimental study, Estudio experimental, Experimentelle Untersuchung, Passivation, Pasivación, Passivierung, Protection corrosion, Corrosion protection, Protección corrosión, Korrosionsschutz, Résistance corrosion, Corrosion resistance, Resistencia corrosión, Korrosionsbestaendigkeit, Traitement chimique, Chemical treatment, Tratamiento químico, Traitement surface, Surface treatment, Tratamiento superficie, and Oberflaechenbehandlung

In order to reduce an exhaust gas, it has been necessary to reduce a weight of automobile. One of the most effective method for the weight reduction of cars is the strengthening of parts. Therefore, in order to reduce the weight of suspension coil springs, the strengthening of spring steels has been carried out in recent years. However, the strengthening of steels brings increase in sensitivity for corrosion fatigue caused by pitting corrosion. Improvement of the pitting corrosion resistance by alloying and chemical passivation treatment was investigated in this research. Measurements of anodic polarization curves were carried out for four commercial production low alloy spring steels and 22 laboratory steels modified on JIS SUP10 in 5 mass% NaCI solution at 308±0.5K. Furthermore, the effect of chemical passivation treatment on the pitting potential was evaluated for the specimens treated in 63 mass% conc. HNO3 solution at 308K. The quasi-pitting potential of V'cq100 corresponding to V'c100 of stainless steels, has been adopted to evaluate the pitting corrosion resistance of low Cr-bearing spring steels. The major results of this research are as follows. (1) The effective alloying elements to improve the pitting corrosion resistance of the low alloy spring steels are Si, Ni, Cr, Cu, Co, Sb, and B. (2) The chemical passivation treatment for 3.6 ks on the practical spring steels containing less above-mentioned alloying elements, is also effective to improve the pitting corrosion resistance. (3) The quantitative alloying design guide based on regression analysis between V'cq100 and content of alloying elements was proposed.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Dépôt de matériaux non métalliques, Nonmetallic coatings, Chronoampérométrie, Chronoamperometry, Cronoamperimetría, Chronoamperometrie, Electrolyse, Electrolysis, Electrólisis, Elektrolyse, Etude expérimentale, Experimental study, Estudio experimental, Experimentelle Untersuchung, Microscopie électronique balayage, Scanning electron microscopy, Microscopía electrónica barrido, Rasterelektronenmikroskopie, Polymérisation électrolytique, Electrochemical polymerization, Polimerización electrolítica, Pyridine(2-vinyl)polymère, Pyridine(2-vinyl) polymer, Piridina(2-vinil) polímero, Revêtement, Coatings, Revestimiento, Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Voltammétrie cyclique, Cyclic voltammetry, and Voltametría cíclica

The effects of electrolysis factors on the formation of poly(2-vinylpyridine) coatings electropolymerized on Zn substrate have been investigated by cyclic voltammetry technique. The amount of poly(2-vinylpyridine) coatings electropolymerized by cyclic voltammetry was significantly dependent on the pH of the bath and the maximum amount of coating was obtained at pH 5. This result suggested that the specific amount of proton in the bath should play an important role in the electropolymerization of 2-vinylpyridine. The morphology of the coatings was evidently affected by the hydrogen evolution. Under the electrolysis conditions where the hydrogen evolution rate was increased, the coatings contained many pits and streaks caused by vigorous hydrogen evolution. The poly(2-vinylpyridine) coatings produced by cyclic voltammetry were fine in the bath of pH 5 at 20 to 30°C. On the other hand, the current density for polymerization by chronoamperometry was abruptly decreased in the initial stage of two-dimensional coating formation, then it was subsequently decreased with an increase in the thickness of sound coating. The anode and cathode current density of Zn plate in 3% NaCl solution was decreased by poly(2-vinylpyridine) coating formation on it.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Nettoyage. Dégraissage. Décapage, Cleaning. Degreasing. Pickling, Acier inoxydable, Stainless steel, Acero inoxidable, Nichtrostender Stahl, Acier, Steel, Acero, Azote oxyde, Nitrogen oxide, Nitrógeno óxido, Stickstoffoxid, Décapage, Pickling, Decapado, Beizen, Electrolyse, Electrolysis, Electrólisis, Elektrolyse, Etude expérimentale, Experimental study, Estudio experimental, Experimentelle Untersuchung, Hydrogène peroxyde, Hydrogen peroxide, Nitrique acide, Nitric acid, Nítrico ácido, Salpetersaeure, Titane, Titanium, Titanio, Titan, Traitement surface, Surface treatment, Tratamiento superficie, and Oberflaechenbehandlung

Synopsis : In order to control NOx gas emissions on pickling both stainless steel and titanium metal with nitric-hydrofluoric acid, a new control system has been investigated in laboratory and tested at a pickling plant, which doses hydrogen peroxide into the pickling bath automatically. The system includes pairs of platinum electrodes and electrolyzers, pumps for injecting hydrogen peroxide solution into the pickling bath, and their controllers. Results of the tests at the pickling plant showed that the NOx gas concentration can be lowered to 50∼200 ppm and consumption of the nitric acid was reduced apparently by dosing hydrogen peroxide so as to oxidize most of nitrous acid on pickling stainless steel, or as to oxidize whole nitrous acid and go to slight excess on pickling titanium metal. It was also verified that the electrolytic current measured in the pickling bath was of use as index which showed the concentration of remaining nitrous acid or hydrogen peroxide excessively added. The amounts of consumed hydrogen peroxide through pickling using this system was about 0.92 or 0.82 mole for one mole of SUS304 or titanium metal, respectively.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Dépôt de matériaux non métalliques, Nonmetallic coatings, Acier, Steel, Acero, Adhérence, Adhesion, Adherencia, Adhaesion, Analyse numérique, Numerical analysis, Análisis numérico, Numerisches verfahren, Couche mince, Thin film, Capa fina, Duennschicht, Ester polymère, Ester polymer, Ester polímero, Etude expérimentale, Experimental study, Estudio experimental, Experimentelle Untersuchung, Revêtement protecteur, Protective coatings, Revestimiento protector, Schutzueberzug, Revêtement, Coatings, Revestimiento, Ueberzug, Résistance corrosion, Corrosion resistance, Resistencia corrosión, Korrosionsbestaendigkeit, Traitement surface, Surface treatment, Tratamiento superficie, and Oberflaechenbehandlung

Synopsis : Various characteristics of biaxially oriented polyester film that is laminated on to steel for can use are controlled by the degree of biaxial orientation and the thickness of amorphous layer of the laminated film. The adhesive property and the corrosion resistance of the steel deteriorate with increasing laminating speed because of decreasing thickness of amorphous layer even at the same degree of orientation. We found that it is effective to maintain the enough contact cooling time of laminated film in order to prevent the amorphous thickness reduction. Because high speed laminating is indispensable for the better productivity, it is important to find the method of keeping the contact cooling time constant. Therefore, this report deals with the result of numerical analysis applied to characterize heat transfer in new laminating process, which was considered and accepted to maintain the contact cooling time by winding the steel along the laminating roll for prevention of decreasing thickness of amorphous layer with increasing laminating speed. Based on the result of numerical analysis, we obtained the transient cross-sectional temperature distribution of polyester film in the laminating process compared with the ordinary laminating process. The thickness of amorphous layer with the numerical analysis obtained by the cross-sectional variation of maximum temperature of film in the roll nip agrees well with the one observed by polarizing microscope. The estimation of the thickness of amorphous layer was found possible by this method with a good accuracy. The variations of biaxial orientation of the laminated film on non-contact side after leaving roll nip in this laminating process is also discussed.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Nettoyage. Dégraissage. Décapage, Cleaning. Degreasing. Pickling, Analyse chimique, Chemical analysis, Análisis químico, Chemische Analyse, Analyse surface, Surface analysis, Análisis superficie, Attaque électrolytique, Electrolytic etching, Ataque electrolítico, Elektrolytisches Aetzen, Décalaminage, Carbon deposit removal, Descalaminado, Entzundern, Décapage, Pickling, Decapado, Beizen, Electrolyse, Electrolysis, Electrólisis, Elektrolyse, Etude expérimentale, Experimental study, Estudio experimental, Experimentelle Untersuchung, SEM, Titane, Titanium, Titanio, Titan, Traitement surface, Surface treatment, Tratamiento superficie, and Oberflaechenbehandlung

Synopsis : A new descaling process for cold rolled and annealed titanium metal strip was developed in order to produce defectfree titanium plates efficiently. The process includes newly introduced electrolysis in certain electrolytes which promotes the descaling in cooperation with the preceding salt bath treatment (immersion in fused alkali-salt mixture) and the following pickling with nitric-hydrofluoric acid. Laboratory study by anodic electrolysis showed that HNO3 or HNO3-NaNO3 solution was most effective electrolyte for promoting descaling, and NaOH-NaNO3, HNO3-H2SO4 or Na2SO4-NaNO3 solution was also effective more or less, but H2SO4, HCl or NaOH solution was scarecely effective. It was also confirmed that intermittent alternate current electrolysis in HNO3 solution promoted descaling without absorbing hydrogen and the current density on the electrolysis was desirable to be 15-20 A/dm2. Chemical analysis of the electrolyte by ICP emission spectroscopy and surface analysis of the specimen by GDS proved that the titanium scale dissolved by the anodic electrolysis, and current measurement on the electrolysis suggested that the dissolution was made easy by the salt bath treatment. Finally, the effectiveness of the electrolysis was verified by a manufacturing test using titanium metal strip.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Dépôt de matériaux non métalliques, Nonmetallic coatings, Acier revêtu plastique, Plastic coated steel, Acero revestido plastico, Plastikueberzogener Stahl, Acier, Steel, Acero, Adhérence, Adhesion, Adherencia, Adhaesion, Couche mince, Thin film, Capa fina, Duennschicht, Diffraction RX, X ray diffraction, Difracción RX, Roentgenbeugung, Ester polymère, Ester polymer, Ester polímero, Etude théorique, Theoretical study, Estudio teórico, Theoretische Untersuchung, Phase amorphe, Amorphous phase, Fase amorfa, Revêtement, Coatings, Revestimiento, Ueberzug, Simulation numérique, Numerical simulation, Simulación numérica, Traitement surface, Surface treatment, Tratamiento superficie, and Oberflaechenbehandlung

Polyester film laminated steel for can container will gradually replace lacquer coated steel sheet from environmental concern and cost consideration. The process of lamination is characterized by partial melting of the film on the surface of steel during lamination by pressing the supplied films between both sides of heated steel and a couple of cooled rubber rolls. Various characteristics of film laminated steel for can use are strongly influenced by the degree of biaxial orientation and the thickness of amorphous layer of the laminated film, and the characteristics are greatly influenced by several laminating conditions. Therefore, this report deals with the result of numerical analysis applied to characterize heat transfer in laminating process, in order to estimate the variation of orientation of the laminated film. From the result of numerical analysis, we found that the cross-sectional temperature distribution in roll nip greatly changes within extremely short time, and the distribution contributes to the formation of double layered structure of amorphous and biaxially oriented layers. Moreover, it was found important to form the double layered structure of the laminated film by keeping an appropriate temperature profile of film in roll nip. The thickness of amorphous layer with the numerical analysis obtained by the cross-sectional variation of maximum temperature of film in the roll nip agrees well with the rune observed by polarizing microscope. The estimation of the thickness of amorphous layer was found possible by this method with a good accuracy.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Dépôt de matériaux non métalliques, Nonmetallic coatings, Acier, Steel, Acero, Calorimétrie différentielle balayage, Differential scanning calorimetry, Análisis calorimétrico barrido exploración, Differentialrasterkalorimetrie, Couche mince, Thin film, Capa fina, Duennschicht, Diffraction RX, X ray diffraction, Difracción RX, Roentgenbeugung, Enthalpie, Enthalpy, Entalpía, Ester polymère, Ester polymer, Ester polímero, Etude expérimentale, Experimental study, Estudio experimental, Experimentelle Untersuchung, Produit laminé, Rolled product, Producto laminado, Walzerzeugnis, Relation orientation, Orientation relation, Relación orientación, Revêtement, Coatings, Revestimiento, Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, and Oberflaechenbehandlung

Synopsis : Polyester film laminated steel for can container will gradually replace lacquer coated steel sheet from environmental consideration and cost reduction. The process is characterized by partial melting of the film on the steel surface during lamination by pressing the supplied films between both sides of heated steel and a couple of cooled rubber rolls. At present, most of polyester films used for the can containers are biaxially oriented films and various characteristics of film laminated steel for can use are strongly influenced by the degree of biaxial orientation of the laminated film. Therefore, this report deals with the result of an experiment regarding variations of the degree of biaxial orientation with several polyester films and thermal analysis of these polyester films by means of Differential Scanning Calorimeter (DSC). Finally, from these experiments. we found that it is possible to estimate the variation of the degree of biaxial orientation during lamination by means of thermal analysis.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Dépôt de métaux et d'alliages, Metallic coatings, Acier galvanisé, Galvanized steel, Acero galvanizado, Acier, Steel, Acero, Adhérence, Adhesion, Adherencia, Adhaesion, Diffraction électron, Electron diffraction, Difracción electrónica, Elektronenbeugung, Etude expérimentale, Experimental study, Estudio experimental, Experimentelle Untersuchung, Microstructure, Microestructura, Mikrogefuege, Propriété mécanique, Mechanical properties, Propiedad mecánica, Revêtement, Coatings, Revestimiento, Ueberzug, SEM, Spectrométrie Auger, Auger electron spectrometry, Espectrometría Auger, Auger Spektrometrie, Ségrégation, Segregation, Segregación, Seigerung, TEM, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Zingage immersion, Hot dip galvanizing, Galvanización con cinc sumergido, and Feuerverzinken

Synopsis : The surface of the annealed steel and the exfoliated interface of the coating for the hot dip galvanized Si containing steel sheets was characterized by using SEM (Scanning Electron Microscope), AES (Auger Electron Spectroscopy) and TEM (Transmission Electron Microscopy). The adhesion of the coatings have depended on the Si content of the steel. It have been found that MnSiO3 particles are formed at the surface of the annealed steels having high Si content and that two types of grain having different distribution of the oxide exist in the steels. Large oxide particles have been formed in one type of grain and small particles are formed in the other type of grain. The different type of Fe-Zn alloy are formed on two types of grains. It have been observed that the oxide particles exist at the interface of exfoliated coatings after the adhesion test for the steels with high Si content. The distribution of the oxide particles observed at the bottom of the exfoliated coating is quite similar to that of the surface oxide of the annealed steel. From these results, the exfoliation of the coating has initiated at the oxide particles of the steel surface that has been not reduced during the hot dip galvanizing.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Corrosion, Protection contre la corrosion, Corrosion prevention, Alliage base fer, Iron base alloys, Couche mince, Thin film, Capa fina, Duennschicht, Dureté, Hardness, Dureza, Haerte, Dépôt électrolytique, Electrodeposition, Depósito electrolítico, Elektroplattieren, Essai corrosion, Corrosion test, Ensayo corrosión, Korrosionsversuch, Essai usure, Wear test, Prueba al desgaste, Verschleissversuch, Etude expérimentale, Experimental study, Estudio experimental, Experimentelle Untersuchung, Nitrique acide, Nitric acid, Nítrico ácido, Salpetersaeure, Propriété électrochimique, Electrochemical properties, Propiedad electroquímica, Elektrochemische Eigenschaft, Protection corrosion, Corrosion protection, Protección corrosión, Korrosionsschutz, Résistance corrosion, Corrosion resistance, Resistencia corrosión, Korrosionsbestaendigkeit, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Usure glissement, Sliding wear, Desgaste deslizamiento, and Gleitverschleiss

Synopsis : Electrodeposition behavior of iron-group metal alloys with W was studied in ammoniacal citrate baths of various compositions at 50°C under galvanostatic conditions. The wear and corrosion resistances of iron-group metal alloys with W were also investigated by sliding wear test of ring-on-plate type at 300°C and dipping test in HNO3, H2SO4 and HF solutions. The results obtained were as follows: ( 1) The relationship between the alloy composition and the cathode current efficiency showed the existence of two characteristic alloy compositions, i.e., the one appeared at a maximum partial current efficiency of W and the other corresponded to the limiting W content. ( 2 ) Electrodeposition behavior of iron-group metal alloys with W was explainable by the mechanism that the intermediate W4+ oxide electrochemically formed was reduced by atomic hydrogen held on freshly deposited iron-group metals. ( 3 ) The wear resistance of iron-group metal alloys with W was improved with increasing W content in the deposit and showed the best performance at 30∼40 mass% W. When W content in the deposit was high, hardness of the film was increasaed to prevent adhesive wear between the film and press ring. Hardening of the film due to the frictional heat also seemed to be contributed to the improvement of wear resistance. ( 4 ) The corrosion resistances of the films were improved with increasing W content in the deposit, especially in HNO3 solutions.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Dépôt de métaux et d'alliages, Metallic coatings, Acier galvanisé, Galvanized steel, Acero galvanizado, Acier, Steel, Acero, Additif, Additive, Aditivo, Zusatzstoff, Brillance, Brightness, Brillantez, Dépôt métal, Metal deposition, Deposición metal, Metallbeschichten, Dépôt électrolytique, Electrodeposition, Depósito electrolítico, Elektroplattieren, Etude expérimentale, Experimental study, Estudio experimental, Experimentelle Untersuchung, Microscopie force atomique, Atomic force microscopy, Microscopía fuerza atómica, Orientation cristalline, Crystal orientation, Orientación cristalina, Kristallorientierung, Revêtement, Coatings, Revestimiento, Ueberzug, Rugosité, Roughness, Rugosidad, Rauhigkeit, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Zinc, and Zink

Zn was electrodeposited on a commercial steel sheet from the sulfate baths containing a small amount of inorganic additives. The lightness and the gloss of deposited Zn were evaluated by the conventional techniques and the morphology was observed using an atomic force microscope. On the basis of their effect on the appearance of deposited Zn, the additives used were classified into following three groups: Fe, Ni, Co, Al, Mg and Mn (Group I). Cr, W, Mo and Zr (Group II) and Cu, Pb, Cd, In, Sn, Ge, Sb and Ag (Group III). The additives of group I hardly affected the morphology, crystal orientation and surface roughness of deposited Zn, and therefore they caused no change in the lightness and the gloss compared with the deposit from additive-free bath. Since the additives of group II enhanced the (0002) orientation index of deposited Zn, the surface roughness decreased significantly. As a result, the lightness and the gloss of deposited Zn increased although the morphology was scarcely affected by these additives. The additives of group III caused a significant change in the morphology of deposited Zn and therefore the surface roughness changed considerably depending on the additive concentration in the baths. With an increase in the additive concentration in the baths, the lightness and the gloss were generally decreased, although the addition of extremely small amount of Cd, Ge, Sb and Ag compounds to the baths increased the lightness and the gloss of deposited Zn.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Dépôt de métaux et d'alliages, Metallic coatings, Addition plomb, Lead addition, Adición plomo, Bleizusatz, Densité courant, Current density, Densidad corriente, Stromdichte, Dépôt électrolytique, Electrodeposition, Depósito electrolítico, Elektroplattieren, Etude expérimentale, Experimental study, Estudio experimental, Experimentelle Untersuchung, Morphologie, Morphology, Morfología, Revêtement, Coatings, Revestimiento, Ueberzug, Spectrométrie photoélectron, Photoelectron spectrometry, Espectrometría fotoelectrón, ESCA Spektrometrie, Traitement surface, Surface treatment, Tratamiento superficie, and Oberflaechenbehandlung

Synopsis : The effect of Pb in the bath on the electrodeposition behavior of Zn-Ni alloys in sulfate type baths was investigated for the hydroxide suppression mechanism. In the presence of Pb in the bath, the transition current density where codeposition behavior changes from normal type to anomalous type was increased. This increase can be explained by the following two factors, one is the current density which is equal to reduction rate from Pb2- ion to Pb as metal, another is the increase of apparent current density because of rough deposits on the electrode surface. The Ni content in deposits increased in the region II where anomalous type codeposition occurred with high current efficiency. This phenomenon appears to have been caused by the metal Pb electrodeposition continuously supplying activation sites for electrodeposition of Ni, which is not blocked in Zn hydroxides, thus accelerating the rate of electrodeposition of Ni, compared to that of Zn.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Elaboration des métaux, Production of metals, Physicochimie des processus métallurgiques, Metallurgical fundamentals, Conduite verticale, Vertical pipe, Conducto vertical, Ecoulement diphasique, Two phase flow, Flujo difásico, Ecoulement, Flow(fluid), Flujo, Fluide Stroemung, Etude expérimentale, Experimental study, Estudio experimental, Experimentelle Untersuchung, Mouillabilité, Wettability, Remojabilidad, Benetzbarkeit, Propriété physique, Physical properties, Propiedad física, Physikalische Eigenschaft, Traitement surface, Surface treatment, Tratamiento superficie, and Oberflaechenbehandlung

Synopsis : The flow pattern of air-water two-phase flows in a vertical, circular pipe was experimentally investigated. The wettability of the pipe was changed by surface treatment. The original acrylic pipe had a contact angle θc of 77°, while two pipes after the surface treatment had θc of 36° and 104°, respectively. The flow patterns in the pipes having θc of 36° and 77° were the same and agreed favourably with previously published results for pipes of good wettability (θc<90°). On the other hand, different types of bubbly and slug flows appeared in the pipe of θc=104°. being caused by attachment of bubbles and slugs to the wall of the pipe. The bubbly flows for θc of 104° were classified into two categories and slug flows for the same contact angle were classified into three categories. The boundary between the bubbly and slug flows, however, was hardly dependent on the wettability of the pipe.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Assemblage et découpage thermique: aspects métallurgiques, Joining, thermal cutting: metallurgical aspects, Soudage, Welding, Acier galvanisé, Galvanized steel, Acero galvanizado, Acier, Steel, Acero, Angle contact, Contact angle, Angulo contacto, Kontaktwinkel, Durée vie, Lifetime, Tiempo vida, Lebensdauer, Etude expérimentale, Experimental study, Estudio experimental, Experimentelle Untersuchung, Film lubrifiant, Lubricating film, Película lubricante, Interface, Interfase, Grenzflaeche, Lubrifiant, Lubricant, Lubricante, Schmiermittel, Silice, Silica, Sílice, Soudage par points, Spot welding, Soldadura punto, Soudage, Welding, Soldadura, Schweissen, Traitement surface, Surface treatment, Tratamiento superficie, and Oberflaechenbehandlung

Synopsis: The effect of a silica-base lubricant film on sliding property and spot weldability of galvannealed steel sheet was investigated by using hat channel drawing with bead and electrode tip life under the SiO2 coating weight of 10-100 mg/m2 in the silica-base lubricant film. (1) Sliding property is improved largely by coating the silica-base film of 10-20mg/m2 as SiO2 on the galvannealed steel sheet. The reason seems to be that the direct contact between galvannealed coating layer and die is prevented by coating silica-base film, then the adhesion at interface between the coating layer and the die is prevented, which decreases the true contact area between the coating layer and die, and consequently improves the sliding property. (2) The spot weldability evaluated by electrode tip life is improved largely by coating silica-base film, because protective layer which is composed of SiO2 and Fe-Zn alloy is formed on the surface of the electrode tip. (3) The silica-base lubricant film has no effect on phosphatability.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Dépôt de métaux et d'alliages, Metallic coatings, Acier, Steel, Acero, Alliage base zinc, Zinc base alloys, Alliage binaire, Binary alloy, Aleación binaria, Analyse surface, Surface analysis, Análisis superficie, Cobalt alliage, Cobalt alloy, Cobalto aleación, Cobaltlegierung, Dépôt électrolytique, Electrodeposition, Depósito electrolítico, Elektroplattieren, Etude expérimentale, Experimental study, Estudio experimental, Experimentelle Untersuchung, Microscopie électronique balayage, Scanning electron microscopy, Microscopía electrónica barrido, Rasterelektronenmikroskopie, Microstructure, Microestructura, Mikrogefuege, Protection corrosion, Corrosion protection, Protección corrosión, Korrosionsschutz, Revêtement protecteur, Protective coatings, Revestimiento protector, Schutzueberzug, Revêtement, Coatings, Revestimiento, Ueberzug, Traitement surface, Surface treatment, Tratamiento superficie, and Oberflaechenbehandlung

Synopsis : Zinc-cobalt electrodeposited steel sheet is adopted for automobile bodies for its high corrosion resistance with small cobalt content. This deposit exhibits fine grains and its refinement mechanism has been discussed. The deposits of various zinc contents have been prepared galvanostatically from sulfate baths and examined by SEM and FESEM. The single η-phase of 99.7 at% zinc exhibits morphology of hexagonal columnar crystal having triangular pyramidal shape with the η-phase plates stacking in the direction of c-axis. At 99.2 at% zinc, finer hexagonal crystals with the same orientation form on the {10.0}η of this hexagonal columnar crystals. With the decrease of zinc content to 98.2 at% zinc these finer hexagonal crystals form in between the larger hexagonal columnar crystals with random orientation. The γ1-phase forms in addition to the η-phase. With further decrease of zinc content to 93.4 at% zinc, larger hexagonal columnar crystals disappears, and the entire deposits become finer hexagonal crystals. The γ-phase forms in addition to the η/γ1-phase.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Dépôt de métaux et d'alliages, Metallic coatings, Diffraction RX, X ray diffraction, Difracción RX, Roentgenbeugung, Dépôt électrolytique, Electrodeposition, Depósito electrolítico, Elektroplattieren, Etude expérimentale, Experimental study, Estudio experimental, Experimentelle Untersuchung, In situ, Orientation préférentielle, Preferred orientation, Orientación preferencial, Bevorzugte Orientierung, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Zinc, and Zink

Synopsis : In order to study the dynamic phenomena of electrodeposition of metallic layers, we have newly developed in-situ X-ray diffraction system using an electrochemical cell and an image-plate detector. Electrodepositions of zinc layers on iron (100), (111) single crystals with current densities of 1.0×103 to 1.0×104 A/m2 were demonstrated. It was found that there were two stages for the preferred orientation of zinc layers. It was dominated by the crystallographic orientation of substrate material at the initial stage and the current density (i.e. overvoltage) at the next stage.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Dépôt de métaux et d'alliages, Metallic coatings, Diffraction RX, X ray diffraction, Difracción RX, Roentgenbeugung, Etude expérimentale, Experimental study, Estudio experimental, Experimentelle Untersuchung, In situ, Rayonnement synchrotron, Synchrotron radiation, Radiación sincrotrón, Synchrotronstrahlung, Revêtement, Coatings, Revestimiento, Ueberzug, Réaction chimique, Chemical reaction, Reacción química, Chemische Reaktion, Traitement surface, Surface treatment, Tratamiento superficie, Oberflaechenbehandlung, Transformation phase, Phase transformation, Transformación fase, Phasenumwandlung, Zingage immersion, Hot dip galvanizing, Galvanización con cinc sumergido, and Feuerverzinken

A new system has been developed for in situ obsevation of phase transformation at high temperatures. Changes in powder diffraction patterns from a heated specimen can be measured continuously by scanning an image plate located behind a slit. A heating system is designed for a sheet specimen (ca. 5×6 mm2) using Joule-heating, and it can heat the specimen up to 1100K at a rate up to 160K/sec, where effects of thermal expansion are minimized by a mechanism releasing stress. This system was applied to Zn-coated steel. At temperatures higher than the melting point of Zn, different types of Fe-Zn intermetallics formed sequentially through rapid inter-diffusion. Changes in phase and crystallographic structure were monitored with a time resolution less than a few seconds. It has been found that an addition of a small amount of elements, such as P, into Fe changes an incubation time before the alloying reaction starts. This system has been shown to have the potential for application to in situ observation of other reactions at high temperatures.