Corrosion failure due to flux residues in an electronic add-on device

Morten Stendahl Jellesen, Daniel Minzari, Umadevi Rathinavelu, Per Møller, Rajan Ambat

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Corrosion of components and sub-assemblies on an electronic Printed Circuit Board Assembly (PCBA) is a major reliability concern. Both process and user related contamination will influence the corrosion reliability of a PCBA and the electronic device as a whole. An important process related contamination is solder flux residues which can act as a corrosion promoter in humid atmosphere due to the presence of ionic substances and a resin component. The presence of ionic substances will increase the conductivity of a condensed water layer and influence corrosion processes, depending on the species present. The resin component can easily attract dust during operation, which will eventually make surfaces hydrophilic and are thus become a potential source for ions. This paper describes the failure analysis of tactile switches, used in PCBAs mounted in wind turbines. More detailed investigation of the electrochemical behavior metallic materials (alloys) used in the switch and risk of electrochemical migration (ECM) between the switch components in presence of flux residues was also carried out. Investigations included potentiodynamic polarization measurements on the switch electrodes using a micro-electrochemical technique, in situ ECM studies, and scanning electron microscopy (SEM). Failure of the switches was found to be either due to the flux residue acting as an nsulating layer or as a corrosion accelerator causing ECM.
Original languageEnglish
JournalEngineering Failure Analysis
Volume17
Issue number6
Pages (from-to)1263-1272
ISSN1350-6307
DOIs
Publication statusPublished - 2010

Keywords

  • Electronic-device failures
  • Corrosion
  • Reliability analysis

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