On-line corrosion monitoring of indoor atmospheres
2004 (English)In: EUROCORR 2004 - European Corrosion Conference: Long Term Prediction and Modelling of Corrosion, 2004Conference paper, Published paper (Refereed)
Abstract [en]
For indoor conditions, risks of corrosion are more easily and more reliably estimated by exposing reference metals, as compared to by analysing climatic conditions and air pollutants. Corrosion of the reference metals can be evaluated as metal loss or metal gain, by electrolytic reduction or by methods permitting more or less continuous corrosion monitoring. Sensitive and continuous monitoring methods would be useful for classifying conditions in permanent or temporary museum displays, for selecting between storage facilities for corrosion sensitive artefacts, for evaluating effects of visitors or effects of air conditioning etc. Commercially available instruments for on-line corrosion monitoring of atmospheres indoors, the quartz crystal microbalance and electrical resistance sensors, have been evaluated for sensitivity, reliability and fitness for use. Additionally, performance of laboratory manufactured electrical resistance sensors is evaluated. These sensors are to be used with a small battery operated corrosion logger currently under development. The corrosion logger is intended for permanent or temporary use, such as in display cases, in cabinets intended for storage of sensitive objects or even in transport packages. A quartz crystal microbalance measures the resonance frequency of a metal-coated quartz crystal. Corrosion of the metal coating leads to the formation of a corrosion film on the surface, increasing the weight of the crystal, decreasing its resonance frequency. Drawbacks of the method are that the readings are slightly temperature dependent and affected by particles and other contaminants on the surface, as well as by moisture films, thus by the relative humidity. With electrical resistance sensors, corrosion is measured as changes in resistance of a thin metal track. The resistance increases when the metal thickness is reduced from corrosion. Since this method measures corrosion directly it is not affected by particles or by the humidity. Common for both methods is that only metals attacked by uniform corrosion are suitable, not metals susceptible to local corrosion such as pitting corrosion. In this investigation, copper and silver coatings have been employed. For both methods the sensitivity was found to be sufficient for monitoring atmospheric conditions in rooms requiring low corrosion rates, such as instrument rooms and museums. Electrical resistance sensors seem to be the sensor type best suited for use under indoors atmospheric conditions. Further development, optimizing sensitivity and variation in response for use with the corrosion logger under development, is needed as well as expanding the range of metals used.
Place, publisher, year, edition, pages
2004.
Keywords [en]
Atmospheric corrosion, Corrosion logger, Corrosion sensor, Electrical resistance sensor, Quartz crystal microbalance, Air pollutants, Atmospheric conditions, Climatic conditions, Continuous monitoring, Corrosion film, Corrosion monitoring, Display case, Electrical resistances, Indoor atmosphere, Indoor conditions, Local corrosion, Metal loss, Metal thickness, Metal-coated, Quartz crystal, Resistance increase, Resonance frequencies, Silver coatings, Storage facilities, Temperature dependent, Thin metals, Uniform corrosion, Atmospheric humidity, Electric resistance, Electrolytic reduction, Metal coatings, Metals, Monitoring, Museums, Natural frequencies, Pitting, Quartz, Quartz crystal microbalances, Risk perception, Sensitivity analysis, Silver plating, Corrosion rate
National Category
Engineering and Technology
Identifiers
URN: urn:nbn:se:ri:diva-40441Scopus ID: 2-s2.0-84867266673OAI: oai:DiVA.org:ri-40441DiVA, id: diva2:1361167
Conference
European Corrosion Conference: Long Term Prediction and Modelling of Corrosion, EUROCORR 2004, 12 September 2004 through 16 September 2004, Nice
2019-10-152019-10-152023-05-26Bibliographically approved