Advancement in the Control and Prediction of CASS Test Performance

摘要

The demand for improved corrosion performance from automotive decorative chromium components has evolved over the last twenty years. This has generally been characterized by the extended CASS test requirement in automotive standards. It is well known that CASS test performance is strongly linked to microporosity, among other deposit attributes. Only recently, one automotive manufacturer adopted a new method for assessing active micropores using the Fuhrmann test instead of the Dubpernell test. The advantage of the new procedure is the direct correlation of the pore count before CASS test to the active sites after CASS exposure. Consequently the Fuhrmann test is effective for predicting corrosion results, assuming all other deposit characteristics such as thickness and STEP comply with the specification. The acceptance of the Fuhrmann test by other OEM's is anticipated due to its improved reliability.