Thick Films Produced by Laser Ablation of Microparticle Aerosols (LAMA)

The Laser Ablation of Microparticle Aerosol (LAMA) process utilizes conventional, low-cost micron sized particles of virtually any inorganic material as a feedstock. The micron-sized powders are aerosolized and ablated using a pulsed laser to produce an aerosol of charged, unagglomerated nanoparticles. The nanoparticles are then accelerated through a supersonic jet to velocities of 400-1200 m/sec and impacted onto a substrate. By rastering the substrate beneath the jet nozzle, thick patterned lines can be directly written at high speeds and at room temperature. Compared to other processes advantages of the LAMA process include: 1) Nanostructured films from virtually any inorganic material can be produced 2) Highly non-equilibrium nanostructured composites can be deposited which exhibit unique and potentially advantageous properties 3) Films with tick nesses of more than 100 µm can be produced 4) Films can be patterned at high velocity and without the need for device-specific tooling 5) Since films are deposited at room temperature, polymeric substrates can be used and 6) the high impaction velocities result in films with higher densities than those produced using colloidal methods while retaining the nanostructure.

We currently are investigating processing/microstructure/property correlations in silver nanostructured films produced by LAMA for use in low temperature electrical interconnects and as a lower temperature seal for MEMS packaging. We are also investigating the use of the LAMA process for producing magnetic actuator devices that can be operated at lower fields and produce larger displacements compared to films produced using other techniques.

This interdisciplinary research project is a collaboration with the Keto and Becker research groups.

Publications

1. A.D. Albert, M.F. Becker, J.W. Keto, and D. Kovar, “Low Temperature, Pressure-Assisted Sintering of Nanoparticulate Silver Films,” Acta Mater. 56, 1820-1829 (2008). Abstract
2. D. Kovar, A.D. Albert, M.F. Becker, and J.W. Keto, “Pressure-Assisted Sintering of Nanocrystalline Silver Lines Produced by Laser Ablation of Microparticle Aerosols,” Proceedings of the ASME Conference on Manufacturing Science and Engineering (MSEC 2007), Advances in Synergistic Effects of Materials and Processing, No. MSEC2007-31170, 2007, Atlanta, GA, October 15-18.
3. C. Huang, M.F. Becker, J.W. Keto, and D. Kovar, "Annealing of Nanostructured Silver Films Produced by Supersonic Deposition of Nanoparticles," J. Appl. Phys. 102, 054308 (2007). Abstract
4. C. Huang, W.T. Nichols, D.T. O’Brien, M.F. Becker, D. Kovar, and J.W. Keto, “Supersonic Jet Deposition of Silver Nanoparticle Aerosols: Correlations of Impact Conditions and Film Morphologies,” J. Appl. Phys. 101, 064902 (2007). Abstract
5. A.D. Albert, C. Huang, M.F. Becker, J.W. Keto, and D. Kovar, “Deposition of Nanostructured Silver Lines and Films from Aerosols Produced by LAMA,” Proceedings of the International Symposium on Synergistic Effects of Materials and Processing (ISSEMP 2006), JSME No. 06-207, pp. 1-6, Japan Society of Mechanical Engineers, Kumamoto, Japan, September 19, 2006. Abstract
6. J.W. Keto, M.F. Becker, D. Kovar, G. Malyavanatham, A. Muller, D.T. O'Brien, C.K. Shih, and J. Wang, "Nanoparticles of Er-Doped Glass Produced by Laser Ablation of Microparticles,"J. Opt. Soc. Am. B., 23 [8] 1581-1585 (2006). Abstract
7. G. Malyavanatham, D.T. O'Brien, M.F. Becker, W.T. Nichols, J. W. Keto, D. Kovar, S. Euphrasie, T. Loue and P. Pernod, "Thick Films Fabricated by Laser Ablation of PZT Microparticles," J. Mat. Proc. Tech., 168 [2] 273-279 (2005). Abstract
8. M.F. Becker, J.W. Keto, and D. Kovar, “Nanoscale Manufacturing-Nonlinear Nanocomposites for Magnetostrictive Actuators and Photonic Devices,” 2005 NSF Design, Service and Manufacturing Grantees and Research Conference Proceedings, pp. 1-5, January 3-6, 2005, Scottsdale, AZ.
9. G. Malyavantham, D.T. O’Brien, M.F. Becker, J.W. Keto, and D. Kovar,  "Au-Cu Nanoparticles Produced by Laser Ablation of Mixtures of Au and Cu Microparticles," J. Nanoparticle Res., 6 [6] 661-664 (2004). Abstract
10. M.F. Becker, J.W. Keto, and D. Kovar, “Nanoscale Manufacturing-Nonlinear Nanocomposites for Magnetostrictive Actuators and Photonic Devices,” Proceedings of the 2004 NSF Nanoscale Science and Engineering Grantees Conference, pp. 1-3, December 13-15, 2004, Arlington, VA.
11. J. Ma, D.T. O’Brien, M.F. Becker, J.W. Keto, D. Kovar, “Nanoscale Manufacturing - Nanocomposites for Magnetostrictive Actuators,” 2004 NSF Design, Service and Manufacturing Grantees and Research Conference Proceedings, January 5-8, 2004, Dallas, TX. Abstract
12. D.E. Henneke, G. Malyavanatham, D. Kovar, W.T. Nichols, J.W. Keto, D.T. O'Brien, and M.F. Becker, "Stabilization of Silver Nanoparticles in Nonanoic Acid: A Temperature Activated Conformation Reaction Observed with Surface Enhanced Raman Spectroscopy,"  J. Chem. Phys., 119 [13] 6802-6809 (2003). Abstract
13. J.W. Keto, W. Nichols, D. O'Brien, M.F. Becker, and D. Kovar, “Nanoparticles: Building Blocks for Nanostructured Materials,” From the Atomic to the Nano-scale, Proceedings of the International Workshop, C. T. Whelan and J. H. McGuire, Eds. (Old Dominion, 2003) pp. 54-62. Abstract

Intermediate Temperature Solid Oxide Fuel Cells
Solid oxide fuel cells (SOFC) can produce electricity with high efficiencies with the advantages of greatly reduced harmful emissions and no moving parts. A critical hurdle to commercialization of SOFC are the high operating temperatures and large thermal expansion mismatch between the cathode and electrolyte that can results in long-term degradation. We are developing low cost ceramic processing techniques that are capable of producing ultra thin electrolytes and exploring new perovskite and perovskite-based cathodes. The combination of thin electrolytes and new low thermal expansion electrolytes that can operate at lower temperatures will allow improved long term performance by reducing thermo mechanical loading on the fuel cell.

This interdisciplinary research project is a collaboration with the Manthiram research group.

Publications

1. C. Torres Garibay, “Manufacturing of Reduced-Dimensions Planar Solid Oxide Fuel Cells Using Inexpensive Ceramic Techniques,” Proceedings of the GEC Graduate Engineering Student Research Conference,The University of Texas at Austin, TX, April 28, 2005.

Cellular Ceramics with Improved Thermo Mechanical Properties
Ceramic foams and honeycombs are two examples of cellular ceramics that are used in reformers, catalytic converters, particulate filters and porous burners. These applications all involve substantial thermo mechanical loading that can result in failure of the foams or honeycombs. We are developing methods for designing and processing of novel cellular ceramics with non-uniform cellular geometries that are capable of sustaining large thermo mechanical loads.

This interdisciplinary research project is a collaboration with the Ellzey and Rodin research groups.

Publications

1. P.J. Elverum, J.L. Ellzey, and D. Kovar, "Material Performance in a Porous Ceramic Burner," in Proceedings of the Spring Meeting of the Western States Section of the Combustion Institute, La Jolla, California, Paper #02S-9, 2002.
2. P.J. Elverum, J.L. Ellzey, and D. Kovar, "Durability of YZA Ceramic Foams in a Porous Burner,"  J. Mat. Sci. 40 155-164 (2005). Abstract

Research is currently supported by

• The National Science Foundation through a NIRT Grant
• The University of Texas at Austin through a University Research Grant

Al₂O₃/Y-TZP particulate composite ceramic

(Collaboration with Prof. Taleff, Mechanical Engineering)

Publications

1. J. Wang, E.M. Taleff, and D. Kovar, "Superplastic Deformation of Al₂O₃/Y-TZP Particulate Composites and Laminates," Acta Mat., 52 [19] 5485-5491 (2004). Abstract
2. J. Wang, E.M. Taleff, and D. Kovar, "High Temperature Deformation of Al₂O₃/Y-TZP Particulate Laminates," Acta Mat., 52 [15] 4685-4693 (2004). Abstract
3. J. Wang, D. Kovar, and E.M. Taleff, “Deformation of Superplastic Al₂O₃/Y-TZP Particulate Composites and Particulate Laminate Composites” in Advances in Superplasticity and Superplastic Forming, ed. by E.M. Taleff, P.A. Friedman, P.E. Krajewski, R.S. Mishra, and J.G. Schroth, pp. 265-273, TMS, Warrendale, PA, 2004. Abstract
4. J. Wang, E. M. Taleff, and D. Kovar, "High-Temperature Deformation of  Al₂O₃/Y-TZP Particulate Composites, " Acta Mat., 51 [12] 3571-3583 (2003). Abstract
5. T. Sullivan, J. Wang, D. Kovar, and E.M. Taleff, "Development of Superplastic Al₂O₃/Y-TZP Duplex Laminates" in Ceramic Transactions Vol 128: Advances in Ceramic-Matrix Composites VII, April 22-25, 2001; pp. 89-100, The American Ceramic Society, Westerville, OH, ed. by N.P. Bansal, J.P. Singh, and H.-T. Lin, 2001. Abstract

In-situ micrographs showing wetting behavior of molten aluminum on TiC coated substrates under different conditions

Publications

M.S. Noel and D. Kovar, "Laser Chemical Vapor Deposition of TiC on Tantalum," J. Mat. Sci. 37 689-697 (2002). Abstract

Highly textured Al₂O₃ produced by a seeding and tape casting process

Publications

1. P.W. Hall, J.S. Swinnea, and D. Kovar, "Fracture Resistance of Highly Textured Alumina," J. Am. Ceram. Soc. 84 [7] 1514-1520, (2001). Abstract
2. P.W. Hall and D. Kovar, "Processing and Fracture Response of Morphologically Textured Alumina"; J. Mat. Proc. Tech., Vol. 117/3 "Special Issue", THERMEC 2000 - Proceedings of the International Conference on Processing and Manufacturing of Advanced Materials. Edited by T. Chandra, K. Higashi, C. Suryanarayana, and C. Tome. Elsevier Science, Las Vegas, NV, 2001. Abstract
3. D. Kovar and P.W. Hall, "Microstructure and Mechanical Behavior of Textured Alumina," in Proceedings of the 12th International Conference on Textures of Materials, August 9-13, 1999, Montreal, Canada; NRC Research Press. ed. by J.A. Szpunar; pp. 1501-1506 (1999). Abstract