REVIEW OF METHODS FOR THE DETERMINATION OF FERROUS- AND ZINC-BASED CORROSION RATES IN AQUEOUS TIMBER PRESERVATIVES CONTAINING COPPER

摘要

A review of methods is presented for techniques that have produced weight loss-, direct current voltammetric- and electrochemical impedance spectroscopy-derived corrosion rates in aqueous copper-based preservatives. Relative rates of mild steel, hot-dipped galvanised steel and AISI 316 stainless steel corrosion are considered. Comparative orders of inverse polarisation resistance, derived from both direct current and alternating current (electrochemical impedance) techniques, were in agreement with the general performance characteristics derived from the standard AWPA E17 weight loss test. The hot-dipped galvanised steel was found to be the most active material in terms of overall metallic losses; especially in contact with the copper-chromearsenate solution. The mild steel was considerably more durable than the galvanised material and AISI 316 exhibited excellent passivation behaviour in all electrolytes.