Electrolytic Colouring of Anodized Aluminium on Tin Basis
Barbora Šopová *, Matilda Zemanová
Institute of Inorganic Chemistry, Technology and Materials, Faculty of Chemical and Food Technology STU in Bratislava, Radlinského 9, 812 37 Bratislava, Slovak Republic
E-mail: * xsopova@is.stuba.sk
Abstract: The aim of the study was to find parameters of electrolytic colouring on tin basis to form uniform black coatings on anodized aluminium. A two steps electrolytic process consisting of aluminium anodization in a sulphuric acid electrolyte and colouring in tin acidic electrolyte was used. Among parameters influencing the colouring process, AC colouring voltage, composition of the counter electrode, and agitation of the colouring electrolyte were studied. Spectrocolorimetry was applied to analyse the quality of the colouring. Thickness of the coloured and sealed anodized specimens was also evaluated. Optimum parameters for uniform colouring of anodized specimens were found. Unfortunately, colouring electrolyte on tin basis is susceptible to oxidation which negatively influences the colouring.
Keywords: aluminium; anodic oxidation; tin based electrolytic colouring; hydrothermal sealing; L*a*b* system
Full paper in Portable Document Format: acs_0319.pdf
Acta Chimica Slovaca, Vol. 12, No. 1, 2019, pp. 8—13, DOI: 10.2478/acs-2019-0002