Cold Spray Coatings for Corrosion Resistance in Acidic Brine Environments

Cold spray application of thin boundary layers of resistant material on more cost effective substrate material presents a wide-ranging opportunity to reduce cost of repair and deployment of new components in increasingly aggressive environments. The potential benefits range from enhanced corrosion resistance, to increased high temperature oxidation protection to wear protection in flowing environments.

This work targets the use of cold sprayed CRAs (corrosion resistant alloys) onto mild steel substrates for improved resistance to CO2-rich brine solutions typical in carbon storage sites. Providing cost-effective protection in these severe chemistries is key to meeting the global demand for reducing the barriers to deployment of CCS solutions. Concern remains for the long term integrity of transmission and storage infrastructure when in prolonged contact with mixtures of impure CO2 streams and acidic brine environments such as those in natural gas storage wells. The EPA's recommended practice of constructing storage strings of 25Cr stainless steel materials is not a cost effective solution across the projected expansion of the CCS need. Through iterative improvement in cold spray application technique and corresponding material resistance analysis in a dedicated CO2 corrosion testing facility, a robust matrix of material combinations and simulated environmental stresses has been investigated. The overall objective of this work was to provide a basis for leveraging the use of these relatively low cost cold spray coatings to improve the overall integrity of low alloy steel infrastructure against the harsh environments that may evolve in storage of complex compositions of emitted CO2.