Material Homogeneity Studies on 3D Microfabricated Ceramic Structures Using Nanoparticle Building Blocks
EMSL Project ID
25644
Abstract
Nanoparticles are required for both geometric and performance attributes in numerous microscale applications. Curiously, numerous synthesis routes for nanoscale powders have been reported yet advantages are poorly realized from these powders. Further, scientific studies relating to the behavior of nanopowder-polymer systems have lagged behind, thereby limiting opportunities in microsystem applications. Thus, there exists a huge gap between nanoscale powder availability and widespread application in microsystems . Shrinking component sizes tax our fabrication abilities. In powder systems, the rule of thumb is that the powder size must be smaller than 5% of the feature dimension to reduce wall effects. Features of 1 µm size require particles below 50 nm. While micromolding with polymers has met with some success, material homogeneity is a significant problem in micro powder injection molding (PIM) because it results in various molding defects in metal or ceramic microparts. Material heterogeneity, or inhomogeneous nanoparticle density distribution, in green parts is related to inhomogeneous feedstock mixtures as well as powder/binder separation occurring in melt flow. The issue becomes more prominent for µPIM because of the small particle sizes and fast mold flow velocity for filling. Small and irregular-shaped particles tend to form agglomerates in feedstock mixture. The fast mold filling may cause more particles to migrate because of the increased shear rate gradient in cavity. These issues lead to some strong interests in studying the influence of nanoscale powder attributes in the evolution of homogeneity problems in mircoparts such as microchannel arrays (MCAs). The objective of the proposed work is to understand material homogeneity issues at the micro and macroscale while fabricating dense, small-scale devices and microstructures by using nanoscale powders. A design of experiments coupled with modeling involving variations in nanoscale alumina particle size and PIM process conditions to map the homogeneity at the macroscale (part level) and microscale (particle level) in ceramic microchannel arrays (MCAs). Several material test methods and techniques have been developed in our recent work for characterizing material homogeneity at the macroscale (component defects) and microscale (powder-polymer distribution) based on green and sintered MCAs [102]. They include cavity pressure and temperature sensors, optical and scanning electron microscopy (SEM), optical surface profilometry, nanoindentation, atomic force microscopy (AFM) x-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (TOF-SIMS). The proposal seeks instrument access for AFM, SEM, XPS, and TOF-SIMS to complement our on-going research.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2007-09-01
End Date
2008-09-07
Status
Closed
Released Data Link
Team
Principal Investigator
Related Publications
Jain, K. Laddha, S.G.; Wu, C.L.; Atre, S.V.; Lee, S.; Simmons, K.; Park, S.J.; and German R.M.; “Ceramic Microarrays for Aggressive Environments,” Proceedings of NSTI Nanotechnology Conference and Trade Show, 2008, in press.
Laddha, S.G.; Wu, C.L.; Atre, S.V.; Lee, S.; Simmons, K.; Park, S.J.; and German R.M., “The Effect of Feedstock Composition on Defect Evolution in Powder Injection Molded Ceramic Microarrays,” Advances in Powder Metallurgy and Particulate Materials - 2008, Metal Powder Industries Federation, Princeton, NJ, in press.
Monfared, N.; Kishton, R.; Prasad, S.; Varadarajan, S. and Atre, S.V.; “The Influence of Pore Structure on the Performance of Nanomaterial-Based Chemical Sensors,” Advances in Powder Metallurgy and Particulate Materials - 2008, Metal Powder Industries Federation, Princeton, NJ, in press.
Wu, C.L.; Laddha, S.G.; Atre, S.V.; Lee, S.; Simmons, K.; Park, S.J.; and German R.M., “Powder Injection Molded Ceramic Microarrays,” Proceedings of Molding 2008.
Wu, C.L.; Laddha, S.G.; Atre, S.V.; Lee, S.; Simmons, K.; Park, S.J.; German R.M.; and Whychell, D., “Microscale Heterogeneity in Powder Injection Molded Ceramic Microarrays,” Powder Injection Molding International, 2008, 2(2), pp. 68-73.
Wu, C.L.; Laddha, S.G.; Atre, S.V.; Lee, S.; Simmons, K.; Park, S.J.; and German R.M., “Powder Injection Molded Ceramic Microarrays,” Proceedings of Molding 2008.
. Laddha, S.G.; Wu, C.L.; Atre, S.V.; Lee, S.; Simmons, K.; Park, S.J.; and German R.M., “The Effect of Feedstock Composition on Defect Evolution in Powder Injection Molded Ceramic Microarrays,” Advances in Powder Metallurgy and Particulate Materials - 2008, Metal Powder Industries Federation, Princeton, NJ, in press.
Monfared, N.; Kishton, R.; Prasad, S.; Varadarajan, S. and Atre, S.V.; “The Influence of Pore Structure on the Performance of Nanomaterial-Based Chemical Sensors,” Advances in Powder Metallurgy and Particulate Materials - 2008, Metal Powder Industries Federation, Princeton, NJ, in press.