Brightener
Brighteners are used to produce glossy surfaces in electroplating . They reduce the crystal size on the workpiece so that a smooth metal surface with a high degree of reflection is created. They are particularly common in nickel plating . In the detergent segment, the term gloss-forming agent includes substances that make the colors appear more intense. Thus, in all systems there is a surface effect, but are subject to different systems.
Gloss bearer
Gloss carriers or primary gloss agents lead to a significant reduction in the size of the precipitated crystallites . However, they do not give a high gloss on their own . They include organic sulfur such as sulfoximides , sulfonamides , benzenesulfonic acids , naphthalene sulfonic acids , alkane sulfonic acids , sulfinic acids and arylsulfone sulfonates . The sulfur is built into the metal layer. The sulphonamide saccharin is a prominent highlight .
Gloss additives
Brightening additives or secondary brightening agents alone result in high-gloss, but mostly brittle metal layers. Together with gloss substrates, a solid high gloss results. Luster additives are organic substances with carbonyl groups such as aldehydes, e.g. B. anisaldehyde , vanillin , piperonal and those with C = S groups such as thiocyanates , thiourea , acylthiourea , sulfanylalkylsulfonic acids , disulfides , thiocarboxylic acid amides , thiocarbamate , thiosemicarbazones and thiohydantoins . The concentrations of the brighteners can be between 1 and 10 g · l −1 .
literature
- Entry to brightener. In: Römpp Online . Georg Thieme Verlag, accessed on March 18, 2014.
- Willibald Machu, Soliman El-Gendi: About the effect of mixtures of several brighteners in electroless nickel baths. Part II . In: Materials and Corrosion / Werkstoffe und Korrosion . tape 12 , no. 6 , June 1961, ISSN 0947-5117 , p. 364–368 , doi : 10.1002 / maco.19610120605 ( PDF ).
- Practical electroplating technology . 4th edition, Eugen G. Lenze Verlag, Saulgau 1984, pp. 268-271