A steel sheet for a fuel tank according to the present invention includes: a Zn—Ni alloy plated layer placed on one surface or each of both surfaces of a base metal; and a chromate-free chemical conversion coating film which is placed over the Zn—Ni alloy plated layer. The Zn—Ni alloy plated layer has a crack starting from an interface with the chromate-free chemical conversion coating film and reaching an interface with the steel sheet, the chromate-free chemical conversion coating film consists of an organosilicon compound consisting of a condensation polymer of a silane coupling agent, a phosphoric acid compound and/or a phosphonic acid compound, a vanadium compound, and a titanium compound and/or a zirconium compound, and a concentration of a total of amounts in terms of metal, per surface, of the phosphoric acid compound and/or the phosphonic acid compound+the vanadium compound+the titanium compound and/or the zirconium compound, is 5 mass % to 20 mass %.

The invention relates to a sheet metal having a deterministic surface structure, the surface structure being impressed into the sheet metal, the surface structure having at least one peak region and at least one valley region, the peak region and the valley region being joined by a flank region. The invention further relates to a method for producing a formed and coated sheet-metal component.

A method for producing a diaphragm for an ultrasonic sensor. In the method, a diaphragm body made of metal material is first provided. Next, an external surface region of the diaphragm body is degreased. The external surface region of the diaphragm body is then pickled. To pre-activate the subsequently applied second passivation layer, a first passivation layer is also deposited on the external surface region as a first layer.

Disclosed herein is an aqueous composition having a pH value at 55° C. in the range from 5 to 9, containing at least two different amino organophosphonic acid derivatives of formula (I)

##STR00001##

where residues R independently of each other are CH.sub.2—PO(OR″).sub.2, residues R′ independently of each other are alkylene residues with 2 to 4 carbon atoms, residues R″ independently of each other are H, Na, K, Li or NH.sub.4; and n is an integer from 0 to 4; and where the at least two different amino organophosphonic acid derivatives differ in the value of n. Further disclosed herein is a concentrate to produce such compositions, a pickling method for pickling metallic substrates making use of the compositions, a coating method for coating metallic substrates including the pickling method and a method of using the compositions for pickling metallic substrates.

A method to treat the magnesium surface to manufacture the metallic assembly with the polymer and magnesium to have excellent bonding strength is disclosed.

As a method to treat the magnesium surface for the bonded coupling of the mixture of the polymer and magnesium, this is a method including, (a) an etching step, wherein the magnesium surface is treated with an acidic solution; (b) a first surface treatment step, wherein the magnesium surface is treated with ultrasonic waves; (c) a second surface treatment step, wherein the magnesium surface is treated with an acidic solution; (d) a first silane coupling processing step, wherein the magnesium surface is treated with ultrasonic waves; (e) a surface activation treatment step, wherein the magnesium surface is treated with acidic solution; and (f) a second silane coupling processing step, wherein the magnesium surface is treated with ultrasonic waves.

Described herein are pretreatment compositions, coated aluminum alloy products, and methods for coating the alloys. The pretreatment compositions include inorganic chemical corrosion inhibitors dispersed in a silane-based matrix and may further include clay particles. The inorganic chemical corrosion inhibitors include rare earth metals and salts thereof. The pretreatment compositions, when applied to the surface of an alloy, inhibit corrosion of the alloys. The pretreatment compositions can be used in automotive, electronics, industrial, transportation, and other applications.

A composite panel having a plurality of carbon plies, a perforated metallic foil comprising several apertures and being directly secured to the plurality of carbon plies, and a protective layer made from resin reinforced with fibers which is secured to the metallic foil. The perforated metallic foil is embedded in the protective layer through its apertures. A free surface of the protective layer forms a top side of the composite panel. The thickness of the protective layer between the top side of the composite panel and the perforated metallic foil is at least 15 micrometers and the perforated metallic foil has a thickness of not more than 30 micrometers. The plurality of apertures in the aggregate defines an open area of not more than 40% of the surface area and a maximum distance between two opposed points in a perimeter of an aperture is equal to or less than 3 mm.

The present invention relates to a surface treatment composition comprising, on the basis of 100 wt % of the solid part of the composition, 20-40 wt % of a water-soluble polyurethane resin, 40-60 wt % of a silane-based sol-gel resin in which three types of silane compounds are cross-linked, 5-15 wt % of a curing agent, 0.5-1.5 wt % of a corrosion inhibitor, 0.1-1.0 wt % of a molybdenum-based compound, 1.0-3.0 wt % of a silane coupling agent; 1.0-2.0 wt % of an organometallic complex, 1.0-2.0 wt % of an acid scavenger, 0.1-1.0 wt % of an aluminum-based compound, and 1.0-2.0 wt % of a lubricant. A ternary hot-dip galvannealed steel sheet treated with a chromium-free surface treatment coating agent, according to an exemplary embodiment in the present invention, has excellent resistance to blackening, alkali and corrosion, and provides excellent effects without concern for problems, in chromium treatment, of additional equipment installation, an increase in manufacturing costs and environmental pollution.

Provided herein is a method for specifically adjusting the electrical conductivity of a conversion coating, wherein a metallic surface or a conversion-coated metallic surface is treated with an aqueous composition which comprises at least one kind of metal ions selected from the group consisting of the ions of molybdenum, copper, silver, gold, palladium, tin, and antimony and/or at least one electrically conductive polymer selected from the group consisting of the polymer classes of the polyamines, polyanilines, polyimines, polythiophenes, and polypryrols.

A corrosion resistant coating including a matrix, corrosion resistant particles dispersed throughout the matrix, and a glass-forming additive is disclosed. The glass-forming additive and one or more materials in the matrix form a glassy-phase when cured. Coated gas turbine engine components and methods for coating components are also disclosed.