Field Exposure Test

Field Exposure Testing of Compound with Specific Exposure Control Measures... 

Field exposure test racks were designed and deployed at three different sites with proper protection. 

Fig. 2.6 a Field exposure test rack at site PI. b Field exposure test rack at site P2. c Field exposure test rack at site P3... 

Three replicates of coated and uncoated panels were exposed at three test sites PI, P2 and P3 up to 48 months (m) and the performance evaluation were carried out at different time interval. Various tests were carried out on test panel and the overview of field exposure tests plans are given in Table 2.6. 

Corrosion rate of weathering steels was found lower with respect to mild steels in accelerated laboratory tests. They corrode most rapidly with respect to field exposure test... 

Field exposure test is a very slow oxidation process whereas the accelerated laboratory test is a very fast oxidation process. Several months/years together are required to get measurable mst on surface of steel panels in field exposure. In accelerated laboratory test rate of oxidation is much faster and rust layers/oxides are formed, very quickly. The rust products/oxides formed in both the cases are identical but their manifestations are different. As a result corresponding morphologies and corrosion rates are vastly different. 

Thermodynamic aspects of multi-oxidant corrosion have been discussed by Giggins and Pettit (1980). The complexity of a given process environment often precludes accurate determination of which type of corrosion should predominate. In such circumstances, it might be necessary to conduct field-exposure tests for proper evaluation of the corrosion behavior of the candidate alloys. 

Field exposure tests (e g. the TAPPI program in pulp bleach washers) and electrochemical current decay tests show pits to propagate more rapidly in JS777. JS700 is therefore the recommended alloy where pitting or crevice corrosion is the primary concern. 

Comparative laboratory and field exposure testing show the following advantages for AMICAL 50 preservative. 

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