A solution containing Cr(VI), Cr(NO3)3 and its complex with an organic acid as well as several commercial solutions containing Cr(III) complexes with an organic acid and additionally CO2+, F-, SO42- ions were used for the studies. Results of the studies obtained in the following commercial solutions: Likonda 2AT, Cr(NO3)3 + malonic acid; Likonda 3Cr5 and Likonda 3CrMC are discussed. Steel coated with chromated Zn coatings was contaminated by some microscopic fungi. The variety of fungi on chromated plates diminished, however the propagules of fungi did not disappear completely. The Likonda 3Cr5 solution diminishes fungi contamination on chromated steel most effectively. In water used to rinse the surface of chromated plates the number of fungi propagules was detected to be higher as compared to that on the plate surface. The least quantity of fungi propagules was detected in water used to rinse plates coated in the Likonda 3Cr5 solution. The main part of fungi detected on chromated plates treated in the Likonda 3Cr5 solution were the fungi of Cladosporium species (C.herbarum, C.cladosporioides). The latter species also dominated on chromated plates coated with zinc and treated with the other solution. It should be mentioned, that on these plates chromated in this solution, Actinomycetes of the Streptomyces group were abundant. After comparison of surfaces of the plates treated in four solutions it has been determined that the surface of the plates treated in the Likonda 3Cr5 passivation solution and exposed to modelling conditions changed least of all. It has been noticed that on the subject studied white porous rust accumulates, the intensity of this process on the surface studied determines both the probability of corrosion and the resistance of the used safety means to the external factors

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Zinc coatings are used to protect metallic parts of automobiles from corrosion. Zinc protective coatings are often chromated additionally treating them in acidic solution of chromium compounds. In recent years new technologies were designed to deposit chromate films of various thickness and resistance on zinc surface from acidic solution of Cr(III) compounds. It has been noticed, that under atmospheric corrosion conditions microscopic fungi are present in the environment affect zinc coating. The aim of the presented study was to determine if zinc coatings treated with Cr(III) solution become more resistant to fungi influence or their resistance diminishes. The analysis of steel plates coated with a zinc film and treated in four different chromium solutions has shown that in all the specimens fungi of Cladosporium herbarium species were detected and their frequency of detection was quite high, sometimes up to 50 %. However, we failed to determine the regularities of distribution of some fungi on the surface of plates chromated in different solution. The comparison of changes in the surfaces of plates treated with the four solutions has shown that the plates treated in the Likonda 3Cr5 passivation solution changed least after being exposed to atmospheric conditions. Chromated plates contaminated with mixtures of different fungi and kept for 60 days at a temperature of (26 ±2) °C under humid conditions were examined by using a scanning electron microscope (EVO 5O XP Carl Zeiss STM AG, Germany) and the peculiarities of their surface damage were determined. The peculiarities of growth of some fungi species were determined on the plates chromated in the Likonda 3Cr5 and Cr(NO₃)₃*9H₂O + malonic acid solutions. Under these conditions the fungi of Chrysosporium merdarium, Fusarium proliferatum, Paecilomyces lilacinus, Penicillium stoloniferum can either generate and promote the damage of metal surface or stabilize its corrosion processes.

http://dx.doi.org/10.5755/j01.ms.17.1.243

Zinc-polymeric coating samples were exposed to different environmental conditions (for 2 years): marine Á dunes on the shore of the Baltic Sea (Neringa), rural-agrarian district of Moletai and the industrial zone of Vilnius. During the whole period of the study 94 species of fungi, were isolated from the exposed samples of zinc-polymeric coating on steel. The zinc-polymeric coatings exposed to marine and rural-agrarian environments were deteriorated most markedly. A scanning electron microscope (SEM) was used to characterize the morphology of the surface. The phase composition of the zinc-polymeric coatings on the steel substrate was analysed by an X-ray diffractometer (XRD). The products formed on the zinc-polymeric coatings were detected by a Fourier transformation infrared spectrometer (FTIR). The effect of environmental conditions on the mass change of the samples was determined by the standard dissolution method. Reference to this paper should be made as follows: Lugauskas, A.; Prosyčevas, I.; Narkevičius, A.; Selskienė, A.; Bučinskienė, D.; Ručinskienė, A.; Binkauskienė, E. 2013. Influence of mitosporic fungi upon zinc-polymeric coatings on steel under the different environment, Journal of Environmental Engineering and Landscape Management 21(3): 199Á208. http://dx.