A surface treated copper foil 1 includes a copper foil 2, and a first surface treatment layer 3 formed on one surface of the copper foil 2. The first surface treatment layer 3 of the surface treated copper foil 1 has a Ni concentration of 0.1 to 15.0 atm % based on the total amount of elements of C, N, O, Zn, Cr, Ni, Co, Si, and Cu, in an XPS depth profile obtained by performing sputtering at a sputtering rate of 2.5 nm/min (in terms of SiO.sub.2) for 1 minute. A copper clad laminate 10 includes the surface treated copper foil 1 and an insulating substrate 11 adhered to the first surface treatment layer 3 of the surface treated copper foil 1.

A method for post-treatment of a chromium finish surface to improve corrosion resistance comprising a) providing a substrate having a chromium finish surface, and at least one intermediate layer between the chromium finish surface and the substrate, selected from the group consisting of nickel, nickel alloys, copper and copper alloys, wherein the chromium finish surface is a surface of a trivalent chromium plated layer, obtained by electroplating the substrate, having the at least one intermediate layer, in a plating bath, the plating bath comprising chromium (III) ions; b) contacting the chromium finish surface with an aqueous solution, comprising a permanganate, at least one compound which is selected from a phosphorus-oxygen compound, a hydroxide, a nitrate, a borate, boric acid, a silicate, or a mixture of two or more of these compounds; c) forming a transparent corrosion protection layer onto the chromium finish surface during step b.

A method for post-treatment of a chromium finish surface to improve corrosion resistance comprising a) providing a substrate having a chromium finish surface, and at least one intermediate layer between the chromium finish surface and the substrate, selected from the group consisting of nickel, nickel alloys, copper and copper alloys, wherein the chromium finish surface is a surface of a trivalent chromium plated layer, obtained by electroplating the substrate, having the at least one intermediate layer, in a plating bath, the plating bath comprising chromium (III) ions; b) contacting the chromium finish surface with an aqueous solution, comprising a permanganate, at least one compound which is selected from a phosphorus-oxygen compound, a hydroxide, a nitrate, a borate, boric acid, a silicate, or a mixture of two or more of these compounds; c) forming a transparent corrosion protection layer onto the chromium finish surface during step b.

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.

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.

A surface-treated copper foil, which is excellent in adhesiveness with an insulating substrate for a high-frequency circuit, and particularly is capable of producing a copper clad laminate where occurrence of blisters are suppressed even when a thermal load due to high temperature press-working is applied. More particularly, it is a surface-treated copper foil for a high-frequency circuit having a heat resisting treated layer formed on a copper foil of 35 μm or less in thickness, in which the heat resisting treated layer is characterized by a film including a quaternary metal oxide of chromium, molybdenum, zinc, and nickel and a compound thereof, characterizes the present invention.

Provided are a copper-clad laminate including an insulating layer containing a resin and a copper foil arranged on at least one surface of the insulating layer, wherein the copper foil is a surface-treated copper foil having a metal-treated layer containing zinc, and a content of zinc in the metal-treated layer is 10 to 2,500 μg/dm.sup.2; a method for producing the copper-clad laminate; and a printed wiring board and a semiconductor package using the copper-clad laminate.

Provided are a copper-clad laminate including an insulating layer containing a resin and a copper foil arranged on at least one surface of the insulating layer, wherein the copper foil is a surface-treated copper foil having a metal-treated layer containing zinc, and a content of zinc in the metal-treated layer is 10 to 2,500 μg/dm.sup.2; a method for producing the copper-clad laminate; and a printed wiring board and a semiconductor package using the copper-clad laminate.

This invention is directed to a process of coating metal in a trivalent chromium conversion-electrolyte coating wherein the metal anode or cathode is subjected to a current density ranging up to about 3.0 amperes per square foot for a period ranging up to 60 minutes.

The present invention relates to a method for increasing the corrosion resistance of a chrome-plated substrate wherein at least one part of a chrome-plated surface of a chrome-plated substrate is dipped into an electrolyte comprising trivalent chromium ions, at least one conducting salt and at least one reducing agent, and afterwards, a trivalent chromium oxide film is formed on the at least one part of the chrome-plated surface by applying a pulse reverse current between the chrome-plated surface and a counter electrode electrically connected with the chrome-plated surface through the electrolyte. Furthermore, the present invention relates to a chrome-plated substrate obtainable by this method.