DD220623A1 - METHOD OF REMOVING HEADED COPIER LAYERS OF METAL SURFACES - Google Patents

Abstract

The inventive solution relates to a method for removing hardened copy layers of metal surfaces. The aim of the invention is to develop a process which, compared with known processes, involves a considerably simplified composition of the electrolytes and thus has a low technical and technological expense. The object is achieved in that a hardened copying layer of metal surfaces, which are not attacked by alkalis electrochemically, is rendered permeable by means of a 5-9% alkali lye by immersion, preferably at a temperature of 333 K, and by means of anodic current pulses of 5. 30 seconds in a Tastverhaeltnis at 1: 3, at an advantageous current density of 6-9 A / dm2, wherein the alkali metal alkali-resistant surfactants, at least 0.4 ml / l can be added. The process according to the invention can be used in the reusability of the carrier metal in the polygraphy and preferably in the electroplating.

Description

Object of the invention

The aim of the invention is to develop a method for removing hardened copying layers of metal surfaces, which compared to the prior art involves a significantly simplified composition of the electrolyte and thus has a low technical and technological expense.

Characteristic of the known technical solutions

A method is known in which the steel surface is electrolytically cleaned in two stages, wherein in the I.Stufe an alkaline electrolyte and in the second stage, a sulfuric acid-based electrolyte is used. In consultation with the working conditions and the composition of the electrolyte short working hours are achieved. Surfactant combinations to form a functional foam blanket to reduce heat and electrolyte loss are added to the electrolyte.

This is followed by a rinsing process and the treatment in the sulfuric acid electrolyte to remove dirt residues and tarnish layers and simultaneous activation of the metal. The objects are switched alternately anodically and katodii, where they are anodically polarized last and then galvanized after a rinsing process. The use of the method in the stripping of metal surfaces with cured copying layers has the disadvantage that the effort is uneconomical and can only be used in continuous processes. A stockpiling of activated carrier metals for later processing is not possible because they become passive again. Information Source: DDR-WP154782

Int.-Cl. C 25 F, 1/06

Title: Process for cleaning steel surfaces in continuous pass lines

Furthermore, a method is known in which a cyanide-free alkaline electrolyte is used for rust removal, pickling and degreasing of steel surfaces, in which the electrolyte of glucose, sodium hydroxide, alkali-resistant surfactant and accelerator composed. The electrolysis is carried out at current densities of 10-15A / dm ² and at a temperature of 30-50 'The disadvantage of this method is that it is too expensive for the stripping of metal surfaces with cured copying layers and does not contain optimal process parameters. Another disadvantage is that the sodium nitride used as an accelerator may interfere with the subsequent coating. Information Source: DDR-WP 84547

Int.-Cl. C 23 b, 1/00 '

Title: Cyanide-free alkaline electrolyte for electrolytic rust removal, pickling and degreasing of steel

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Explanation of the essence of the invention

The invention has for its object to develop a method which is suitable for removing cured copy layers of metal surfaces. According to the invention, the object is achieved by making a cured copying layer of metal surfaces, which are not significantly attacked by alkalis electrochemically, by means of a 5-9% alkali Laug <by dipping, preferably at a temperature of 333K is made current-permeable and by anodic StromstöC from 5-30 seconds and a duty factor to 1: 3, at an advantageous current density of 6-9A / dm ² , wherein the Alkalilauc alkali-resistant surfactants, at least 0.4ml / l can be added, is removed.

The process steps of this inventive solution are that the metal surface is immersed with the cured copying layer in a 5-9% alkali at 333 K. The residence time is up to 30 minutes, depending on the copy layer thickness, until the highest conductivity is reached. Subsequently, the metal surface is subjected to anodic current pulses of 5-30 seconds, a pulse duty factor up to 1: 3 and advantageous current densities of 6-9 A / dm ² and then rinsed with deionized water.

The aim of the invention is to eliminate the deficiencies in the prior art in such a way that the technological, material and technical effort for the removal of impurities and coatings on metal surfaces is substantially reduced and simultaneously with the process delamination of metal surfaces with cured copying to be able to make.

The inventive method for removing hardened copy layers of metal surfaces becomes such a defect

eliminated. ,

The electrolyte consists of one, a maximum of two components, which can be easily dosed and monitored, further accounts for subsequent process steps interfering ions,

Furthermore, the stripping is metalloid-saving with minimal metal removal, so that a long life and reusability of the carrier metal is guaranteed.

Field of application of the invention

The invention relates to a method for removing hardened copy layers of metal surfaces. It ensures reusability of the support metal in the polygraphy and preferably in the galvanoforming.

embodiment

The invention is illustrated below with reference to an embodiment:

In a suitable container, matrix bodies for electroforming are to be cleaned of the copying layer and then stored for later use or for immediate reuse. To carry out the procedure sipd apply the following steps: '... \.' '.-

1. Composition electrolyte: preferably 90 g / l NaOH

at least 0.4 ml / l Tepon: '' - - preferably the temperature of 333 K '.

Dive time 30 minutes, depending on the copy layer thickness to be removed

3. Decoating: ahodic surges 9A / dm ² , 15seconds

Duty cycle 1: 3 .. Duration5min; Λ

4. rinsing: with deipnate -;

   ν

Claims (2)

Invention claims: 1. A method for removing cured copying layers of metal surfaces, characterized in that a hardened 'copy layer of metal surfaces, which are not attacked by alkalis electrochemically, made by means of a 5-9% alkali by leaching, preferably at a temperature of 333 K. and by means of anodic surges of 5-30 seconds and a duty ratio of up to 1: 3, with an advantageous current density of 6-9 A / dm ² . 2. A method for removing cured copy layers of metal surfaces according to item 1, characterized in that the Akalilauge alkali-resistant surfactants, at least 0.4 ml / l are added.