The application of microelectronic computer control systems in field locations has developed rapidly over the last 15 years. These distributed control systems (DCS) are far more prone to corrosion damage than earlier control systems. Of particular concern are locations where sulfur species may be present such as hydrogen sulfide, sulfur dioxide, or elemental sulfur. Failures of critical components may occur in as little as three months in locations where humidity, temperature, and corrosive gasses are not adequately controlled. Temporary relief may be obtained by the use of vapor phase corrosion inhibitor (VCI) powders and sprays. A more permanent solution is the installation and maintenance of an adequate air handling system that removes pollutants and controls humidity and temperature. This paper reports a number of different failures that occurred in one plant including general corrosion of circuit boards and a history module and corrosion fatigue of copper conductor wires on an electronics circuit board. Field data on different solutions to the problem are presented.

Subject
Hydrogen sulfide, Sulfur, Circuits, Humidity, Corrosion failures, Corrosion fatigue, Metal coupons, Transformers, Fractures, Lead, Corrosion products, Vibration, Copper
Government work published by the Association for Materials Protection and Performance (AMPP) with permission of the author(s). Positions and opinions advanced in this work are those of the author(s) and not necessarily those of AMPP. Responsibility for the content of the work lies solely with the author(s).
2007
GOV
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