The present disclosure relates generally to the field of conversion coating. More specifically, the present disclosure relates to improved methods for improving efficiency of chromium conversion coat processing lines.

The present disclosure relates generally to the field of conversion coating. More specifically, the present disclosure relates to improved methods for improving efficiency of chromium conversion coat processing lines.

There is provided a steel sheet for cans including, on a surface of a steel sheet, a chromium metal layer and a hydrated chromium oxide layer stacked in this order from the steel sheet side. The chromium metal layer has a coating weight of 50 to 200 mg/m.sup.2, and the hydrated chromium oxide layer has a coating weight of 3 to 30 mg/m.sup.2 in terms of chromium amount. The chromium metal layer includes a base portion of flat plate shape and granular protrusions provided on the base portion. At least 20% of the granular protrusions has a circularity C of 0.85 or less. The circularity C is expressed by C=4?A/U.sup.2, when the outer perimeter of a projection image of a granular protrusion is represented by U, and the area thereof is represented by A.

There is provided a steel sheet for cans including, on a surface of a steel sheet, a chromium metal layer and a hydrated chromium oxide layer stacked in this order from the steel sheet side. The chromium metal layer has a coating weight of 50 to 200 mg/m.sup.2, and the hydrated chromium oxide layer has a coating weight of 3 to 30 mg/m.sup.2 in terms of chromium amount. The chromium metal layer includes a base portion of flat plate shape and granular protrusions provided on the base portion. At least 20% of the granular protrusions has a circularity C of 0.85 or less. The circularity C is expressed by C=4?A/U.sup.2, when the outer perimeter of a projection image of a granular protrusion is represented by U, and the area thereof is represented by A.

Provided is a copper foil. The copper foil includes a copper layer and a protective layer disposed on the copper layer, wherein a surface of the protective layer has a maximum height roughness (R.sub.max) of 0.6 m to 3.5 m, a peak density (PD) of 5 to 110, and an oxygen atomic amount of 22 at % (atomic %) to 67 at %.

The present disclosure relates generally to the field of conversion coating. More specifically, the present disclosure relates to improved methods for improving efficiency of chromium conversion coat processing lines.

The present disclosure relates generally to the field of conversion coating. More specifically, the present disclosure relates to improved methods for improving efficiency of chromium conversion coat processing lines.

The present disclosure relates generally to the field of conversion coating. More specifically, the present disclosure relates to improved methods for improving efficiency of chromium conversion coat processing lines.

An acidic treatment liquid processing apparatus includes: a tank having an interior space; a diaphragm permeable to a metal cation and separating the interior space of the tank into a first chamber and a second chamber; a first electrode disposed in the first chamber; a second electrode disposed in the second chamber; a power supply configured to apply a voltage while using the first electrode as an anode and the second electrode as a cathode; a first liquid passing part configured to pass an acidic treatment liquid containing a dichromate ion and a metal cation into the first chamber; and a second liquid passing part configured to pass an acid aqueous solution into the second chamber.