A condition monitor for atmospheric induced stress corrosion cracking

A sacrificial sensor has been designed to detect the occurrence and rate of atmospheric corrosion and stress corrosion cracking. The sensor fixture was constructed using additive manufacturing and can be customized for use with small size wires or ribbons of any metallic material as a sensor electrode. Resistance change was used to monitor the degradation of arrays of small samples subjected to various stress and environmental conditions. Typical passive atmospheric corrosion sensors do not account for applied stress, or if they do, use statically loaded electrodes and stress relaxation during SCC precludes extended monitoring. However, this sensor allows for propagation of SCC to be monitored since the electrode experiences a dynamic applied stress. This low cost test system permits detection of degradation across multiple time and length scales and can be tailored for the intended application and environment. For proof of concept testing the sensor was used to detect corrosion and stress corrosion cracking of austenitic stainless steels exposed to liquid and high humidity corrosive environments.