Validation of salt spray corrosion test

Abstract

Quality control of corrosion test results implies the validation of the corrosion test method and estimation of the uncertainty of corrosion rate measurement. The corrosion test in an artificial atmosphere of the salt spray mist needs evaluation of corrosivity of the test cabinet by reference specimens. Such calibration of corrosion environment raises very strict requirements for the method description and details of all procedures and used specimens. Reliable corrosion measurements by spray tests require validation of the experimental device together with the experimental procedure and determination of corrosivity uncertainty of the test cabinet environment.

Corrosion tests have been conducted for a long time but there are only a few cases of corrosion data quality assessment or interlaboratory comparisons for such measurements. Each test method when used in different laboratories gives different results, as it is impossible to perform the whole procedure exactly in the same manner. Therefore, a very essential parameter of the method is its robustness. A proper validation of the corrosion test method means the evaluation of the impact of various environmental features and performance variations on the uncertainty of the test result.

Our aim was to present an experimental evaluation of the corrosivity of the salt spray corrosion test cabinet, to indicate the gaps in the description of the corrosion test method according to ISO 9227 and to estimate the main components of the uncertainty of the corrosivity measurement.

The validation results require changes in the salt spray test method description and maybe in the performance.