Sulfuric acid and tartaric acid in tartaric sulfuric anodizing bath – Rapid, sequential determination using a thermometric sensor (thermometric titration)

Tartaric Sulfuric Anodizing (TSA) is an established technique for corrosion protection in the aerospace industry. It is an alternative to the environmentally harmful chromic anodizing process. As such, a method to monitor the levels of sulfuric acid and tartaric acid in TSA plating baths is required. Potentiometric titration methods have been developed, and are widely used across the industry. Their disadvantage is that two titrations with different electrodes and solvents are required.

In this Application Note, an alternative method is presented, where the concentration of both acids is determined in sequence using a thermometric sensor. Compared to potentiometric titration, thermometric titration is faster, more robust (no matrix interferences), and more convenient (no sensor maintenance required). On a fully automated system, the determination of both parameters takes about 7 minutes.