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Purpose - The purpose of this paper is to verify the capability of pigmented coatings to mitigate the effects of thermal sensitisation of 430 stainless steel. Design/methodology/approach - Experimental weld joints of non-stabilised ferritic corrosion resistant steel type AISI 430 were prepared. Protective coatings in several variants were applied to a number of weldments, subsequently subject to corrosion tests in SO2 and NaCl. The anticorrosive efficiency of the coatings was evaluated by means of normative visual assessment and metallographic analysis of the mechanism and depth of corrosion damage. Findings - Anticorrosive efficiency of the tested coatings was experimentally established under conditions where differences were identified in structural changes caused by welding, or resulting from mechanical damage to the coating. Differences in the progress of corrosion damage caused by phase changes in the heat-affected zone were established. Practical implications - Tests of anticorrosive efficiency of coatings of selected types provided information about possible reduction in sensitisation of welded non-stabilised steel. The effect of the investigated processes on degradation of anticorrosive resistance was identified. Originality/value - A specific effect of phase changes accompanying welding on the corrosion mechanism was described and so were the reasons underlying development of corrosion damage at visually identical character of surface damage. Anglická klíčová slova: stainless steel; coatings; pigments; corrosion; destabilisation; welding; corrosion resistant ferritic steels; anticorrosive pigment; zinc; organic coating Práce se zabývá možnostmi zvýšení korozní odolnosti svařovaných korozivzdorných ocelí. V místě sváru a jeho okolí dochází ke zcitlivění materiálu na korozní působení. V práci jsou testovány možnosti zvýšení korozní odolnosti na těchto senzibilizovaných materiálech po povlakování pigmenovanými nátěry s různým složením.

The properties of calcined kaolins in paints were identified in relation to their pigment volume concentration (PVC). The study involved three kinds of kaolin exhibiting different development of the lamellar structure of primary particles as well as different distribution of particle size. Kaolins also displayed varying contents of a glassy phase – mullite and quartz. Prepared model paints were formulated with the increasing content of kaolins, with PVC ranging from 5 to 40% up to a maximum critical pigment concentration (CPVC), i.e. up to a point where PVC = CPVC. The properties of paints were tested by means of laboratory corrosion tests in the environments of neutral salt mist and of condensed humidity. It was the aim of the study to identify the effect of kaolin's PVC on the mechanical and corrosion resistance of coatings based on water-borne epoxy resin.

Driers are added to air drying paints to accelerate the hardening of spread coating. For decades cobalt octoate has been the most widely used drier because of its good performance at ambient temperature. Recently, several reports describing possible carcinogenity and genotoxicity of cobalt and cobalt salts, such as cobalt sulfate in aerosols, have appeared. It is necessary to reduce the amount of cobalt compounds in coatings industry. Present study deals with the possibility of using ferrocene and its derivatives as driers for air drying coatings. We concentrated particularly on the synergic effect between these metallocene complexes and the cobalt drier. In the first step the kinetics of autooxidation by FTIR spectroscopy in model systems was investigated. Then the metallocene complexes were applied together with cobalt drier to alkyd resin, where their influence on hardness of spread coatings was examined.

The objective of this work was to identify the anticorrosive efficiency of synthesised, core pigments. Epoxy ester based coatings containing the synthesised pigments were formulated. To test the anticorrosion properties of the coatings, accelerated corrosion tests were carried out in the environment of condensed water, of NaCl mist, and of condensing water and SO2. The synthesised core shell pigments have good anticorrosion efficiency in an epoxy ester coating. The synthesised pigments do not contain any environmentally harmful substances.