ELECTRIC DEPOSITION OF TIN-LEAD ALLOY BY PULSE CURRENT

The process of electrodeposition of a tin-lead alloy from hydrofluoride electrolytes by pulsating currents has been investigated. The influence of the electric mode on the alloy composition and properties of the resulting precipitates was studied: current efficiency, microhardness, specific electrolytic resistance, and internal stresses of the precipitates.

RESEARCH OF THE PROCESS OF DEPOSITION OF GALVANIC COPPER SEDIMENTS BY PULSE CURRENTS

Research has been carried out on the process of copper electrodeposition from fluoride-hydrogen-boron electrolytes of copper plating by pulsed currents. The influence of the electric mode on the quality of the obtained copper deposits was studied: copper current efficiency, microhardness, specific electrolytic resistance, and internal voltages of the deposits.

In-Situ Evaluation of the Protectivity of Coatings Applied to Metal Cultural Artefacts Using Non-Destructive Electrochemical Measurements

Electrochemical Noise Measurement (ENM) and DC electrolytic resistance measurement (ERM) can be used to assess the level of protectiveness provided by an organic coating (paint or varnish) to the underlying metal. These techniques also have applicability to the thinner, transparent type of coatings used to protect archaeological artefacts. Two studies are presented here demonstrating how ERM and ENM techniques can be applied in artefact preservation. The similarity of the techniques, both of which are a measure of resistance, means results can be considered to be analogous. The first study investigated the use of ERM to determine the protection levels provided by typical coatings in order to develop a database of coating type and application for objects, for specific environments. The second study used ENM to evaluate coatings which had been applied to historic artefacts recovered from shipwrecks in the Baltic Sea and displayed inside the museum or kept in the museum store area. The studies showed the usefulness of both techniques for determining the level of protection of a coating and how a better performing coating can be specified if a pre-existing coating on an artefact has been found to be unsuitable.

Protection of Mg Alloys against Galvanic and Other Forms of Corrosion

Galvanic corrosion is a particularly important form of corrosion for Mg alloys used in automobiles. Our research work focuses on corrosion protection using cost-effective Cr-free coatings. The top-tanking coatings are found to be effective in preventing general corrosion; some of these coatings are also good for reducing galvanic corrosion and stress corrosion. A practical approach for mitigating galvanic corrosion is to increase the electrolytic resistance between the coated steel and the Mg surfaces. This has been demonstrated in the case of a conversion coating plus a powder coat applied on the surface of a magnesium alloy and in the case of a thin Mylar isolation layer installed between the Mg and the steel surfaces.