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Title
Verfahren zur Abscheidung von Chromschichten als Hartverchromung, Galvanisierungsbad sowie hartverchromte Oberflaechen und deren Verwendung
Date Issued
2006
Author(s)
Bohnet, J.
Metzner, M.
Krassnitzer, H.
Schermanz, K.
Patent No
102006035871
Abstract
(B3) Die Erfindung betrifft ein Verfahren zur Abscheidung von Chromschichten als Hartverchromung fuer den Verschleiss- oder Korrosionsschutz und/oder zu dekorativen Zwecken sowie ein Galvanisierungsbad, mit dem derartige Chromschichten abgeschieden werden koennen. Ebenso betrifft die Erfindung hiernach hergestellte hartverchromte Oberflaechen.
WO 2008014987 A2 UPAB: 20080229 NOVELTY - A component is connected as a cathode and immersed in a catholyte comprising chromium (III) salt(s) and compound(s) stabilizing chromium (II) ions. An anolyte comprising a Bronsted acid is separated from the catholyte by an anion-selective membrane. Measuring device(s) is used for continuously monitoring the deviation in pH from a preset value, and controller(s) is used for adjusting the pH to the preset value by automated addition of acid or base. Chromium layers are deposited using the above-mentioned arrangement. DETAILED DESCRIPTION - A component is connected as a cathode and immersed in a catholyte comprising chromium (III) salt(s) and compound(s) stabilizing chromium (II) ions. An anolyte comprising a Bronsted acid is separated from the catholyte by an anion-selective membrane. Measuring device(s) is used for continuously monitoring the deviation in pH from a preset value, and controller(s) is used for adjusting the pH to the preset value by automated addition of acid or base. Chromium layers are deposited using the above-mentioned arrangement. The chromium (III) salt is ammonium chromium alum, potassium chromium alum, chromium chloride, and/or chromium sulfate. The stabilizing compound is amino acid, urea, aliphatic, aromatic-aliphatic, cycloaliphatic or aromatic amine and/or amide. Boric acid/borate, citric acid/citrate, aluminum3+/aluminum sulfate, oxalic acid/oxalate, and/or tartaric acid/tartarate are added as buffer substance to the catholyte for buffering the pH of catholyte. Anionic and/or neutral surfactants chosen from sodium lauryl sulfate, sodium dodecyl sulfate, polyethylene glycol, diisohexyl sulfosuccinate, 2-ethylhexyl sulfate, diisobutyl sulfosuccinate, diisoamyl sulfosuccinate, and isodecyl sulfosuccinate are added as wetting agent to the catholyte. The anolyte contains sulfuric acid. An INDEPENDENT CLAIM is included for electroplating bath. USE - Deposition of chromium layers for protection against wear/corrosion, or for use as decorative chrome plating, is used for producing hard-chrome surfaces (claimed). ADVANTAGE - The method forms chrome surfaces having high hardness. Mixing of anolyte with catholyte is prevented by anion exchange membrane.
Language
de
Patenprio
DE 102006035871 A: 20060801