Evolution of micro-pores in Ni-Cr alloys via molten salt dealloying.
Lin-Chieh Yu, Charles Clark, Xiaoyang Liu, Arthur Ronne, Bobby Layne, Phillip Halstenberg, Fernando Camino, Dmytro Nykypanchuk, Hui Zhong, Mingyuan Ge, Wah-Keat Lee, Sanjit Ghose, Sheng Dai, Xianghui Xiao, James F Wishart, Yu-Chen Karen Chen-Wiegart
Author Information
Lin-Chieh Yu: Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, NY, USA.
Charles Clark: Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, NY, USA.
Xiaoyang Liu: Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, NY, USA.
Arthur Ronne: Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, NY, USA.
Bobby Layne: Chemistry Division, Brookhaven National Laboratory, Upton, NY, USA.
Phillip Halstenberg: Department of Chemistry, University of Tennessee, Knoxville, TN, USA.
Fernando Camino: Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY, USA.
Dmytro Nykypanchuk: Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY, USA.
Hui Zhong: National Synchrotron Light Source II (NSLS-II), Brookhaven National Laboratory, Upton, NY, USA.
Mingyuan Ge: National Synchrotron Light Source II (NSLS-II), Brookhaven National Laboratory, Upton, NY, USA.
Wah-Keat Lee: National Synchrotron Light Source II (NSLS-II), Brookhaven National Laboratory, Upton, NY, USA.
Sanjit Ghose: National Synchrotron Light Source II (NSLS-II), Brookhaven National Laboratory, Upton, NY, USA.
Sheng Dai: Department of Chemistry, University of Tennessee, Knoxville, TN, USA.
Xianghui Xiao: National Synchrotron Light Source II (NSLS-II), Brookhaven National Laboratory, Upton, NY, USA.
James F Wishart: Chemistry Division, Brookhaven National Laboratory, Upton, NY, USA.
Yu-Chen Karen Chen-Wiegart: Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, NY, USA. Karen.Chen-Wiegart@stonybrook.edu.
Porous materials with high specific surface area, high porosity, and high electrical conductivity are promising materials for functional applications, including catalysis, sensing, and energy storage. Molten salt dealloying was recently demonstrated in microwires as an alternative method to fabricate porous structures. The method takes advantage of the selective dissolution process introduced by impurities often observed in Molten salt corrosion. This work further investigates Molten salt dealloying in bulk Ni-20Cr alloy in both KCl-MgCl and KCl-NaCl salts at 700 ���, using scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction (XRD), as well as synchrotron X-ray nano-tomography. Micro-sized pores with irregular shapes and sizes ranging from sub-micron to several microns and ligaments formed during the process, while the Molten salt dealloying was found to progress several microns into the bulk materials within 1-16 h, a relatively short reaction time, enhancing the practicality of using the method for synthesis. The ligament size increased from���~���0.7 ��m to���~���1.3 ��m in KCl-MgCl from 1 to 16 h due to coarsening, while remaining���~���0.4 ��m in KCl-NaCl during 16 h of exposure. The XRD analysis shows that the corrosion occurred primarily near the surface of the bulk sample, and CrO was identified as a corrosion product when the reaction was conducted in an air environment (controlled amount sealed in capillaries); thus surface oxides are likely to slow the morphological coarsening rate by hindering the surface diffusion in the dealloyed structure. 3D-connected pores and grain boundary corrosion were visualized by synchrotron X-ray nano-tomography. This study provides insights into the morphological and chemical evolution of Molten salt dealloying in bulk materials, with a connection to Molten salt corrosion concerns in the design of next-generation nuclear and solar energy power plants.
References
Nano Lett. 2022 Jun 22;22(12):4963-4969
[PMID: 35687425]
