Biocorrosion of Copper Under the Impact of Microscopic Fungi

Abstract

A study is performed of the micromycete biocorrosion of electrical copper M1E and fiberglass FR4 with copper coating, which are used in the production of printed circuit boards. The structure of the surfaces of corroded samples is studied via optical and electron microscopy. Energy dispersive X-ray spectroscopy is used to perform a qualitative and semi-quantitative analysis of chemical elements present in the composition of corrosion products after exposing samples to a bed of micromycetes. An X-ray phase analysis of the products of copper biocorrosion is performed. It is established that microorganisms adhere to the metal surface at the initial stage of micromycetic corrosion, and colonies of them develop. It is suggested that reactive oxygen species (superoxide anion-radical and hydrogen peroxide) participate in the biocorrosion of copper and the functioning of the zerovalent copper–hydrogen peroxide system, triggering a cascade of reactions that result in the destructive oxidation of copper. The role of biofilms of the microscopic fungal colony as the main factor in the mycological corrosion of copper is explained.