Disclosed is a stainless steel having excellent surface electrical conductivity for a fuel cell separator. According to an embodiment of the disclosed stainless steel having excellent surface electrical conductivity for a fuel cell separator, a value of the following surface oxide atomic ratio (1) may be 0.5 or less, as measured on the surface of a stainless steel containing 15 wt % or more of Cr by X-ray angle-resolved photoemission spectroscopy using an Al-Kα X-ray source under the condition where a take-off angle of photoelectrons is from 12° to 85°.

[00001]$\begin{array}{cc}\frac{\begin{array}{c}\mathrm{sum}\mathrm{of}\mathrm{atomic}\mathrm{concentrations}\left(\mathrm{at}\%\right)\\ \mathrm{of}\mathrm{metal}\mathrm{elements}\mathrm{in}\mathrm{metal}\mathrm{oxide}\left(\mathrm{MO}\right)\end{array}}{\begin{array}{c}\mathrm{sum}\mathrm{of}\mathrm{atomic}\mathrm{concentrations}\left(\mathrm{at}\%\right)\\ \mathrm{of}\mathrm{metal}\mathrm{elements}\mathrm{in}\mathrm{total}\mathrm{oxides}\mathrm{and}\mathrm{hydroxides}\end{array}}& \left(1\right)\end{array}$

The metal oxide (MO) includes a mixed oxide: M represents an alloying element other than Cr and Fe or a combination thereof in the matrix; and O represents oxygen. The total oxides and hydroxides include a Cr oxide, a Cr hydroxide, an Fe oxide, an Fe hydroxide, and the metal oxide (MO).

Disclosed is an electrical steel sheet with an insulating coating formed by applying a surface-treatment agent to at least one surface of the electrical steel sheet and drying the surface-treatment agent, wherein the surface-treatment agent contains: certain trialkoxysilane and/or dialkoxysilane (A); a silane coupling agent (B) that does not contain a polymerizable unsaturated group in its structure; plate-like silica (C); a polymerizable unsaturated-group-containing compound (D); and water, within a range satisfying the following conditions (1) to (3): (1) a mass ratio (A/B) of (A) to (B) is from 0.05 to 1.00; (2) a content of (C) is 2 mass % to 30 mass % with respect to a total mass of (A) to (D) in the surface-treatment agent; and (3) a content of (D) is 2 mass % to 18 mass % with respect to the total mass of (A) to (D) in the surface-treatment agent.

Disclosed is an electrical steel sheet with an insulating coating formed by applying a surface-treatment agent to at least one surface of the electrical steel sheet and drying the surface-treatment agent, wherein the surface-treatment agent contains: certain trialkoxysilane and/or dialkoxysilane (A); a silane coupling agent (B) that does not contain a polymerizable unsaturated group in its structure; plate-like silica (C); a polymerizable unsaturated-group-containing compound (D); and water, within a range satisfying the following conditions (1) to (3): (1) a mass ratio (A/B) of (A) to (B) is from 0.05 to 1.00; (2) a content of (C) is 2 mass % to 30 mass % with respect to a total mass of (A) to (D) in the surface-treatment agent; and (3) a content of (D) is 2 mass % to 18 mass % with respect to the total mass of (A) to (D) in the surface-treatment agent.

Disclosed is a system for maintaining a pretreatment bath containing a pretreatment comprising a Group IVB metal. The system comprises an aqueous reducing agent comprising a metal cation and a latent source of sulfate which, upon reaction with a contaminant in the pretreatment bath, forms a metal sulfate. The contaminant comprises a nitrite source. The metal sulfate salt has a pKsp of 4.5 to 11 at a temperature of 25° C. Also disclosed is a method for maintaining a pretreatment bath containing a pretreatment composition comprising a Group IVB metal. The method comprises supplying the reducing agent to the pretreatment bath in an amount sufficient to reduce a pollution ratio of the pretreatment bath to less than 1:1. Also disclosed are substrates with a pretreatment bath maintained according to the system and method.

The present invention relates to metals or metal alloys comprising a protective silicate glass-like coating, and methods for coating the metals or metal alloys. The methods comprise removal of any existing oxide layer from the metal or metal alloy, formation of a new oxide layer on the metal or metal alloy using chemical passivation or exposure to a gaseous oxidising environment, coating the oxidised metal or metal alloy with an aqueous silicate solution, and curing the coating.

The present invention relates to metals or metal alloys comprising a protective silicate glass-like coating, and methods for coating the metals or metal alloys. The methods comprise removal of any existing oxide layer from the metal or metal alloy, formation of a new oxide layer on the metal or metal alloy using chemical passivation or exposure to a gaseous oxidising environment, coating the oxidised metal or metal alloy with an aqueous silicate solution, and curing the coating.

A novel method of blackening surgical needles is disclosed. Surgical needles having outer surfaces are first placed into a first pretreatment bath having a novel composition. The needles are then placed into a second blackening bath having a novel composition for a sufficient period of time to effectively blacken the surfaces of the needles. The novel methods for blackening the surfaces of a stainless steel alloy surgical needle provide a chromium (VI)-free alternative to current needle manufacturing processes. Another unique feature of this novel method is its short processing time. The blackening processes of the present invention can be utilized for in-line treatment processes which can be easily incorporated into high speed needle manufacturing processes, such as strip mounted processes. In addition, the processes of the present invention are readily adaptable to batch processes. Also disclosed are novel systems for blackening surgical needles and novel blackening baths for surgical needles.

A novel method of blackening surgical needles is disclosed. Surgical needles having outer surfaces are first placed into a first pretreatment bath having a novel composition. The needles are then placed into a second blackening bath having a novel composition for a sufficient period of time to effectively blacken the surfaces of the needles. The novel methods for blackening the surfaces of a stainless steel alloy surgical needle provide a chromium (VI)-free alternative to current needle manufacturing processes. Another unique feature of this novel method is its short processing time. The blackening processes of the present invention can be utilized for in-line treatment processes which can be easily incorporated into high speed needle manufacturing processes, such as strip mounted processes. In addition, the processes of the present invention are readily adaptable to batch processes. Also disclosed are novel systems for blackening surgical needles and novel blackening baths for surgical needles.

A steel sheet for a container according to the present invention includes: a base steel sheet; a metal chromium layer; and a chromium-containing layer, in which the metal chromium layer is located on at least one surface of the base steel sheet, the chromium-containing layer is located on the metal chromium layer and contains a granular trivalent chromium compound, or contains a granular trivalent chromium compound and granular metal chromium, the metal chromium layer and the chromium-containing layer are separately disposed in two layers on the base steel sheet, in the chromium-containing layer, an average particle size of the trivalent chromium compound and the metal chromium is 10 nm or more and 100 nm or less, and an adhesion amount of the chromium-containing layer is 1.0 mg/m.sup.2 or more and 100 mg/m.sup.2 or less in terms of a Cr content.

The present inventions refers to a passivation composition for depositing a chromium-comprising passivation layer on a zinc or zinc-nickel coated substrate, the composition comprising: (i) trivalent chromium ions, (ii) at least one complexing agent for the trivalent chromium ions, being different from the at least one corrosion-inhibiting agent, and (iii) at least one corrosion-inhibiting agent, which is (A) one or more than one substituted azole compound and/or salts thereof, together in a total concentration below 10 mg/L, based on the total volume of the passivation composition, and/or (B) one or more than one unsubstituted or substituted aliphatic organic acid with at least one mercapto-group and/or salts thereof, together in a total concentration in a range from 0.001 mg/L to 100 mg/L, based on the total volume of the passivation composition.