M. Saleem, S. Krishnan, D. Beery, and A. Kabansky, "Examining the Corrosion Resistance of Chromium-Passivated Stainless-Steel Tubes," Micro, February 1998, Vol 16, No 2, February 1998, pp 43-51.

Abstract: Welded samples of chromium-rich oxide passivated (CrP) tubing and electropolished (EP) tubing were evaluated for their corrosion resistance. The weldments were exposed to VLSI grade Chlorine (Cl2) gas supplied to a GaSonics plasma etcher tool. Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS) were used to evaluate the weld beads and heat-affected zones (HAZ) of the CrP and EP samples. It was found that the EP weld bead and HAZ suffered severe corrosion as indicated by the presence of numerous particles. XPS analysis showed that EP tubing contained ~20 and ~24 atomic% Cl2 in the weld and HAZ, respectively, after the corrosion test. In addition, the penetration of Cl2 extended into the bulk of the EP tubing. In contrast, the CrP weld and HAZ showed excellent resistance to corrosion. The weld and HAZ showed absence of corrosion-induced particles. The Cl2 content in the and HAZ showed excellent resistance to corrosion. The weld and HAZ showed absence of corrosion-induced particles. The Cl2 content in the weld and HAZ of CrP tubing was minimal, in the range of ~2 and ~4 atomic%, respectively. Chromium oxide is chemically inert to corrosive gases such as Cl2 and, consequently, no penetration of Cl2 was observed into the bulk. Thus, the excellent corrosion resistance of the CrP tubing, weld and HAZ to halogen gases is demonstrated in this study.