Method for reducing concentration of iron ions in a trivalent chromium electroplating bath, including: (i) providing the trivalent chromium electroplating bath including trivalent chromium ions, and iron ions, (ii) subjecting at least a portion of the bath to air agitation, to obtain an air-agitated portion of the bath, (iii) contacting the air-agitated portion with an ion exchange resin, to obtain a resin-treated portion of the bath, and (iv) returning the resin-treated portion of the bath to the trivalent chromium electroplating bath,
provided that the bath provided in step (i) was or is utilized for electrodepositing chromium on a substrate applying a cathodic current density of 18 A/dm.sup.2 or more, after step (iii), iron ions in the resin-treated portion have a lower concentration than in the air-agitated portion, and after step (iv), iron ions in the bath have a concentration below 50 mg/L.

Method for reducing concentration of iron ions in a trivalent chromium electroplating bath, including: (i) providing the trivalent chromium electroplating bath including trivalent chromium ions, and iron ions, (ii) subjecting at least a portion of the bath to air agitation, to obtain an air-agitated portion of the bath, (iii) contacting the air-agitated portion with an ion exchange resin, to obtain a resin-treated portion of the bath, and (iv) returning the resin-treated portion of the bath to the trivalent chromium electroplating bath,
provided that the bath provided in step (i) was or is utilized for electrodepositing chromium on a substrate applying a cathodic current density of 18 A/dm.sup.2 or more, after step (iii), iron ions in the resin-treated portion have a lower concentration than in the air-agitated portion, and after step (iv), iron ions in the bath have a concentration below 50 mg/L.

A method for depositing a zinc-nickel alloy on a substrate, including: (a) providing the substrate, (b) providing an aqueous zinc-nickel deposition bath as catholyte in a compartment, wherein the compartment includes an anode and anolyte, the anolyte being separated from catholyte by a membrane, and the catholyte includes nickel ions, complexing agent, zinc ions, (c) depositing zinc-nickel alloy onto the substrate, wherein after step (c) nickel ions have lower concentration than before step (c), (d) rinsing the zinc-nickel coated substrate in water, obtaining a rinsed zinc-nickel coated substrate and rinse water including a portion of the complexing agent and nickel ions, wherein (i) a portion of rinse water and/or a portion of catholyte is treated in a first treatment compartment to separate water from the complexing agent and the nickel ions, (ii) returning the separated complexing agent to the catholyte, and (iii) adding nickel ion to the catholyte.

Method for filtering a platinum bath by electrodialysis, including consecutive steps of extracting fluid from the platinum bat by an extraction current; filtering the fluid extracted during the extraction step, carried out by electrodialysis in a filtering device having an electrodialysis reactor; supplying the platinum bath with the fluid from the filtering step, by a filtered bath current; all of these steps being carried out in a continuous flow.

The invention relates to an anode for use in electroplating applications for highly alkaline electroplating electrolytes based on sodium hydroxide for depositing zinc and zinc alloys onto steel substrates and die-cast zinc substrates.

The invention relates to an anode for use in electroplating applications for highly alkaline electroplating electrolytes based on sodium hydroxide for depositing zinc and zinc alloys onto steel substrates and die-cast zinc substrates.

Methods and apparatus for electroplating material onto a substrate are provided. In many cases the material is metal and the substrate is a semiconductor wafer, though the embodiments are no so limited. Typically, the embodiments herein utilize a porous ionically resistive plate positioned near the substrate, the plate having a plurality of interconnecting 3D channels and creating a cross flow manifold defined on the bottom by the plate, on the top by the substrate, and on the sides by a cross flow confinement ring. During plating, fluid enters the cross flow manifold both upward through channels in the plate, and laterally through a cross flow side inlet positioned on one side of the cross flow confinement ring. The flow paths combine in the cross flow manifold and exit at the cross flow exit, which is positioned opposite the cross flow inlet. These combined flow paths result in improved plating uniformity.

A process and a system for cleaning excess aluminum from coating baths, e.g. anodization bath solutions, so that they can be reused in an effective manner is provided. The process comprises first passing a portion of the anodization bath solution having excess aluminum through a strong acid cation exchange column in a Na+ form, allowing the effluent to age thereby precipitating cryolite from the effluent; removing the precipitated cryolite from the effluent and then passing the effluent through a strong acid cation exchange column in the NH4+ form, in a preferred embodiment back through the first column, to restore NH4+ to the anodization bath solution and then adding the effluent back in to the anodization bath solution.

A process and a system for cleaning excess aluminum from coating baths, e.g. anodization bath solutions, so that they can be reused in an effective manner is provided. The process comprises first passing a portion of the anodization bath solution having excess aluminum through a strong acid cation exchange column in a Na+ form, allowing the effluent to age thereby precipitating cryolite from the effluent; removing the precipitated cryolite from the effluent and then passing the effluent through a strong acid cation exchange column in the NH4+ form, in a preferred embodiment back through the first column, to restore NH4+ to the anodization bath solution and then adding the effluent back in to the anodization bath solution.

An apparatus for electroplating which is applicable to the electroplating of workpiece is disclosed. The apparatus includes: an electroplating solution container, a target, an absorbent piece, and a power supply. All the electroplating solution, workpiece, absorbent piece, and target are placed inside the electroplating solution container with at least partial portions of each workpiece, absorbent piece and target submerged in the electroplating solution. The positive electrode of the power supply is electrically connected to the target while its negative electrode is electrically connected to the workpiece and absorbent piece simultaneously. When the power supply imposes a current through the circuit, the target releases metal ions into the electroplating solution and metal ions reduce and a metal coating is formed on the workpiece. In the meantime, carbocations in the electroplating solution are adsorbed on the absorbent piece.