Study of the Dissolution of the Barium Sulfate (001) Surface with Hydrochloric Acid by Atomic Force Microscopy

• Published in: Journal of colloid and interface science Vol. 219; no. 1; pp. 212 - 215
• Main Authors: Wang, Kang-Shi, Resch, Roland, Koel, Bruce E., Shuler, Patrick J., Tang, Yongchun, Chen, Huey-jyh, Yen, Teh Fu
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 01.11.1999; Elsevier
• Subjects: atomic force microscopy; barium sulfate; Chemistry; dissolution; etch pit; Exact sciences and technology; General and physical chemistry; General, apparatus; HCl; Surface physical chemistry; barium sulfate; HCl; atomic force microscopy; etch pit; dissolution; Hydrochloric acid; Atomic force microscopy; Surface properties; Crystal face; Experimental study; Crystal morphology; Dissolution; Barium sulfate; Surface structure
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1006/jcis.1999.6473

Noncontact atomic force microscopy (NC-AFM) has been used to investigate the morphological changes of a freshly cleaved (001) surface of barium sulfate (barite) etched with an aqueous solution of 0.1 M HCl at room temperature. Shallow triangular etch pits with a height of 3.6 Å were developed in atomically flat (001) terraces. The etching of the surface was found to proceed in a layer-by-layer dissolution process. Because the crystal structure of barite exhibits a two-fold screw axis parallel to the c axis, “alternating” etch pits were formed, with any two consecutive etch pits pointing opposite to each other. These etch pits became deeper and more elongated along the b axis with time.