Microcracking in Bioceramics

Microcracking in brittle materials can result in significant, at times even dramatic, changes in elastic moduli, fracture strength, fracture toughness and other physical properties. In conjunction with Professor Baumann and her students, my group is investigating microcracking and its implications for hydroxyapatite (HA), a bioceramic that is of considerable interest as an engineered bone material. Microcracking in HA potentially impacts both the mechanical properties and the biological function of HA.

Processing and Characterization of Thermoelectric Materials

Semiconducting thermoelectric materials are of considerable interest in the conversion of waste heat to electric energy. This work consists of two separate projects (one supported by the Department of Energy and by the other by the Office of Naval Research). The Department of Energy (DOE) project is focused on waste heat recovery from internal combusion engines and involves collaboration with Cummins Diesel Engine, Inc. in Indiana as well as the Jet Propulsion Laboratory in Pasadena, California. The Office of Naval Research (ONR) project involves shipboard applications of thermoelectric materials. In both projects, my group is involved with powder processing, powder characterization and hot pressing of thermoelectric materials. In addition, we characterize the elastic moduli, hardness and fracture properties of the thermoelectric materials.

Reviewed Journal Publications

Ren, F.; Case, E. D.; Timm E. J.; Schock, H. J. "Hardness as a function of composition for n-type LAST thermoelectric material," Journal of Alloys and Compounds, accepted for publication (2007).

Pilchak, A. L.; Ren, F.; Case, E. D.; Timm E. J.; Schock, H. J. "Characterization of the particle size distribution for LAST (Lead-Antimony-Silver-Tellurium) powders," accepted for publication, Philosophical Magazine (2007).

Ren, F.; Case, E. D.; Timm E. J.; Schock, H. J. "Young's modulus as a function of composition for an n-type lead-antimony-silver-telluride (LAST) thermoelectric material," accepted for publication, Philosophical Magazine (2007).

Hogan, T. P.; Downey, A.; Short J.; D'Angelo, J.; Wu, C-I; Quarez, E.; Androulakis, J.; Poudeu, F. P.; Sootsman, J.; Chung, D-Y; Kanatzidis, M. G. ; Mahanti, S. D.; Timm, E.; Schock, Ren, F.; Johnson, J.; Case, E. D. "Nanostructured Thermoelectric Materials and High Efficiency Power Generation Modules," Journal of Electronic Materials, 36[7], 704-710, (2007).

Smith, I. O.; Baumann, M. J.; Case, E. D. "Induced Microcracking Affects Osteoblast Attachment on Hydroxyapatite Scaffolds for Tissue Engineering," American Journal of Biochemistry and Biotechnology 2, 105-110, (2006).

Singh, D.; Lorenzo-Martin, M. D; Gutierrez-Mora, F; Routbort, J. L.; Case, E. D. Self-joining of zirconia/hydroxyapatite composites using a plastic deformation process, Acta Biomaterialia, 2[6], 669-675, (2006).

Smith, I. O.; Ren, F.; Baumann, M. J.; Case, E. D. "CLSM as a tool for imaging cancellous and cortical bone," Journal of Biomedical Materials Research B. 79B(1), 185 - 192, (2006).

Ren, F.; Case, E. D.; Timm E. J.; Jacobs, M. D.; Schock, H. J. "Weibull analysis of the biaxial fracture strength of a cast p-type LAST-T thermoelectric material," Philosophical Magazine Letters, 86[10], 673 - 682, (2006).

Smith, I. O.; Baumann, M. J.; Case, E. D. "Three-Dimensional Microstructural Characterization of Porous Hydroxyapatite Using Confocal Laser Scanning Microscopy (CLSM)," International Journal of Applied Ceramic Technology, 2[3], 200 - 211, (2005).

Meganck, J.A.; Baumann, M.J.; Case, E.D.; McCabe, L.R.; Allar, J.N. "Biaxial Flexure Testing of Dense Tissue-Engineered Calcium Phosphate Bioceramics," Journal of Biomedical Materials Research 72A(1), 115-126, (2005).

Case, E.D.; Smith, I.O.; Baumann, M.J. "Microcracking and porosity in calcium phosphates and the implications for bone tissue engineering," Materials Science and Engineering A 390[1-2], 246-254, (2005).

Singh, D.; Gutiérrez-Mora, F.; de la Cinta Lorenzo-Martin, M.; Routbort, J. L.; Case, E.D. "Plastic Deformation of Hydroxyapatites and its Application to Joining," International Journal of Applied Ceramics Technology 2[3], 247-266, (2005).

Hoepfner, T.P.; Case, E.D. "An estimate of the critical grain size for microcracks induced hydroxyapatite by thermal expansion anisotropy", Materials Letters 58: 489 -492, 2004.

Case, E.D.; Ren, Fei; Kwon, Patrick; Kok, Chee Kuang; Rachedi, Robert; Klenow, Bradley "Machining and ceramic/ceramic joining to form internal meso-scale channels", International Journal of Applied Ceramic Technology 1[1]: 95 - 103, 2004.

Draeger, D. J.; Case, E. D. "Engineering The Surface Texture and Shape of Channels in Ceramic Substrates," Materials Science and Engineering B 97(1), 94-105, (2003).

Shin, H. W.; Case, E. D.; Kwon, P. "Fabrication of Internal Channels in Ceramics and Ceramic Composites," Journal of Advanced Materials 35(2), 28-35, (2003).

Zeng, L; Crimp, M. A.; Case, E. D. "The Interfacial Microstructure of Joined Single Crystal and Polycrystalline Alumina," Materials Science and Engineering A360, 228-236, (2003).

Hoepfner, T. P.; Case, E. D. "The Influence of the Microstructure on the Hardness of Sintered Hydroxyapatite," Ceramics International 29(6), 699-706, (2003).

Books, Chapters, Monographs

Case, E. D. "Microwave Processing of Ceramics", Encyclopedia of Chemical Processing (ECHP), pp. 1687 - 1697, Sunggyu Lee, Editor, Marcel Dekker Inc, New York, NY., Invited encyclopedia article, (2006).

Conference Proceedings

Baumann, M. J.; Case, E. D. "Pores Needed for Biological Function Could Paradoxically Boost Fracture Energy in Bioceramic Bone Tissue Scaffolds," accepted for publication, Ceramic Transactions.

Case, E.D.; Ren, F.; Dams, E.E. "Fabricating composition gradients in ceramic/ceramic composites by utilizing the Brazil-Nut Effect to segregate powder particles, pp. 401 - 406, Proceedings of the Fifth International Conference on High Temperature Ceramic Matrix Composites, American Ceramic Society, Westerville OH (2004).

Ren, F.; Case, E.D. "Tensile strength of partially sintered alumina/zirconia composites using diametral compression testing", pp. 365 - 370, Fifth International Conference on High Temperature Ceramic Matrix Composites, American Ceramic Society, Westerville OH (2004).

Kwon, P.; Kok, C.K.; Fickes, D.; Somerton, C.W.; Shin, H.W.; Case, E.D. "Issues in Joining of Ceramic Micro-Heat Exchangers." In Ceramics Transactions, C.A. Lewinsohn, M. Singh and R. Loehman, Eds.; American Ceramic Society: Westerville OH. 138, 209-219, (2003).

Case, E.D. "Selection and Function of Interlayer Materials in Ceramic/Ceramic Joining." In Ceramics Transactions, C.A. Lewinsohn, M. Singh and R. Loehman, Eds.; American Ceramic Society, Westerville OH. 138, 3-28, (2003).

Shin, H.W.; Kwon, P.; Case, E.D. "Joining Zirconia, Alumina and HAP Bioceramics." In Ceramics Transactions, C.A. Lewinsohn, M. Singh and R. Loehman, Eds.; American Ceramic Society, Westerville OH., 138, 149-158, (2003).

Shin, H.W.; Case, E.D.; Kwon, P.; Ren, F.; Kok, C.K. "Machining and Joining to Form Complex Internal Meso-Scale Channels in Ceramic Oxides." In Ceramic Engineering and Science Proceedings W.M. Kriven; H. T. Lin, Eds.; American Ceramic Society, Westerville OH. 24(4), 573-582, (2003).