MSE Colloquium: Dr. Ken Sandhage, Fluid/Solid Reaction Processing of Advanced Materials for Renewable Energy

Reilly Professor of Materials Engineering, School of Materials Engineering, Purdue University

All dates for this event occur in the past.

264 MacQuigg Labs
105 W. Woodruff Ave
Columbus, OH 43210
United States

Abstract

Advanced materials, and the cost-effective manufacturing of such materials, are needed for critical components in renewable energy systems. Fluid/solid reaction processes can provide attractive means of producing complex-shaped components with desired chemistries for such energy applications. Two approaches developed by the Sandhage group will be discussed: i) a liquid/solid reaction process for fabricating ceramic/refractory metal composite heat exchangers1 (and other components) for concentrated solar power (CSP), and ii) a gas/solid reaction process for generating microporous silicon structures for battery anodes2,3 (and other devices).

CSP plants utilize focused solar thermal energy to heat working fluids to drive turbines to create electricity. To enable large-scale use of CSP-derived electricity (with dramatic reductions in man-made CO2 emissions), a significant enhancement in the heat-to-electricity conversion efficiency may be achieved by operating at higher turbine inlet temperatures using high-pressure working fluids (e.g., >750oC with a supercritical CO2 working fluid at >20 MPa). However, a major technological barrier to such operation has been the lack of stiff, mechanically-robust, compact heat exchangers capable of efficient heat transfer at >750oC and >20 MPa (i.e., the maximum allowed stresses of cost-effective metal alloys used for such heat exchangers decrease appreciably above 550oC). Composites of zirconium carbide and tungsten provide an attractive combination of thermal conductivity, stiffness, and failure strength at >750oC. Heat exchanger plates comprised of these robust composites have been fabricated by the low-cost forming of porous WC plates followed by chemical conversion via the following liquid/solid reaction:

{Zr} + WC(s) = ZrC(s) + W(s)

where {Zr} refers to zirconium present within a Zr-Cu liquid. The pressureless reactive infiltration of this Zr-bearing liquid into porous, channel-bearing WC plates has yielded dense ZrC/W composites that retained the channel patterns and plate dimensions (to within 1%).

A gas/solid reaction process has been developed by the Sandhage group to generate porous silicon structures for energy, optical, and other applications. A variety of biogenic and synthetic 3-D SiO2 preforms have been converted into Si-bearing replicas by the following reaction:

2Mg(g) + SiO2(s) = 2MgO(s) + Si(s)

Selective MgO dissolution has then yielded porous Si structures retaining the 3-D shapes and fine (down to nanoscale) features of the SiO2 preforms. The highly-porous and nanocrystalline nature of the resulting 3-D Si structures is attractive for battery anodes, sensors, and other devices.

Bio

Ken H. Sandhage received a B.S. in Metallurgical Engineering from Purdue University and a Ph.D. in Ceramics from the Massachusetts Institute of Technology. After working as a Senior Scientist on the processing of optical fibers at Corning, Inc., and oxide superconductors at American Superconductor Corp., he joined the Department of Materials Science and Engineering at The Ohio State University (1991). In 2003, he joined the School of Materials Science and Engineering at the Georgia Institute of Technology, where he was the B. Mifflin Hood Professor. Since 2015, he has been the Reilly Professor in the School of Materials Engineering at Purdue. A key thrust of the Sandhage group has been the development of shape-preserving fluid/solid reactions to generate advanced materials for energy, aerospace, medical, environmental, and other applications. Sandhage is a Fellow of the American Ceramic Society.

1. M. Caccia, et al., “Ceramic/Metal Composites for Heat Exchangers in Concentrated Solar Power Plants,” Nature, 562 (7727) 406 (2018); 2. A. Xing, et al., “A Magnesiothermic Reaction Process for the Scalable Production of Mesoporous Silicon for Rechargeable Lithium Batteries,” Chem. Commun., 49, 6743 (2013); 3. Z. Bao, et al., “Chemical Reduction of Three-Dimensional Silica Micro-Assemblies into Microporous Silicon Replicas,” Nature, 446 (7132) 172 (2007).