Synergistic mechanism of green corrosion inhibitors COS and CMC-Na in Co electrochemical mechanical polishing

Electrochemical mechanical polishing (ECMP), through the introduction of electric field, promotes the chemical reaction during polishing. However, the addition of electric field will accelerate the oxidative corrosion, at this time the effective corrosion inhibitor must be added in the polishing solution. Nevertheless, most traditional corrosion inhibitors are toxic and inhibition efficiency is low. In order to meet this technical challenge, this paper investigates the effect of two green corrosion inhibitors, chitosan oligosaccharide (COS) and carboxymethylcellulose sodium (CMC-Na), on Co ECMP, and compares them with the traditional inhibitor TAZ. The results show that when COS and CMC-Na are added at the same time, the polished Co surface quality can be greatly improved, and the surface roughness decreases by 94.6 %. It indicates that adding COS and CMC-Na simultaneously can play the best corrosion inhibition effect and achieve the best surface quality. The synergistic behavior and action mechanism of COS/CMC-Na are analyzed by polishing experiments, static corrosion, electrochemical tests, XPS, and AFM. This study provides a reference for the development of green polishing solutions for Co ECMP.