Nanomaterials - Special focus on Solgel derived nanomaterials (metals, sulfides and oxides). Currently the role of organic surfactant and precursors to reduce the agglomeration tendencies are under investigation. Both experimental and theoretical models are being developed to study the critical particle size dependence in phase transformation. An innovative electroless method has been developed to dope transition metal oxide for improved mechanical and electronic properties required in various sectors of automotive, energy and power industries.

Structure Property Relationship - A project from NSF is aimed to study chalcogenide glasses. These materials possess a degree of structure immediate range order (IRO) and a reversible structural bistability. Both X-ray photoelectron spectroscopy and EXAFS has been used to understand the physical and chemical nature of the glass involving IRO. The main focus is to study the homopolar (As-As or S-S) and heteropolar (As-S) bond population in these glasses and any structure variation is correlated to the change in the non-linear (n) index of the glass.

Surface Engineering - Thin films, high temperature coatings, microelectronics. Special RF sputtering is developed to form 10-50 nm nitride particles. Furthermore, innovative metal electroless coatings are developed to convert solid waste materials to conductive fillers. Another project investigates the high temperature surface modification of Fe-Cr-Al fibers. Extensive use of XPS is being fruitful to understand the superalloy oxidation in air and ceramic matrix composite surface alteration in air and water vapor environment at elevated temperatures. Research in physics of sample preparation to analyze insulating materials using AES and FIB are in progress.

Surface Alteration and Corrosion Inhibitors - Research is focused to understand the multiphase corrosion of steels. FIB and XPS are used to evaluate the inhibitor and corrosion chemistry in multiphase flow. Near Edge X-ray Absorption Fine Structure Spectroscopy (NEXAFS) is used to probe the molecular orientation of an organic molecule on a steel substrate. Dr. Seal’s research group found that the microstructure is important in the adsorption kinetics. Their experimental verification in molecular orientation on metal substrates is very close to the theoretical models proposed by CALTECH group. Surface modification during CMP of W, Cu and Ta, vital for Lucent’s 0.25mm technology. An insitu electrosurface chemistry chamber was developed to correlate the static dissolution at acidic and basic slurries to any surface alteration.

Selected Publications

S. Seal, K. Richardson et al., “Structure and Chemical Studies of As2S3 Glasses Used for Waveguide Applications”, Journal of Physics and Chemistry of Glasses, 43(1), 59-65, 2002.

S. Wannaparhun, S. Seal, K. Scammon, V. Desai, “Physics of Insulator Sample Preparation for Electron Beam Characterization”, J. Applied PhysicsD, 34, 3319-3326, 2001.

S. Shukla, S. Seal, D. Zhou, S. Swartz, Synthesis and Characterization of Nanocrystalline Silver Coating of Flyash Cenosphere Particles by Electroless Process”, J of Nanoscience and Nanotechnology, 1, 417-424, 2001.

S. Shukla, S. Seal, “Cluster Size Effect Observed for Gold Nanoparticles Synthesized by Sol-Gel Technique as Studied by X-ray Photoelectron Spectroscopy”, Nanostr. Mater./Acta Mater., Vol. 11, 1999, 1181.

S. Seal, S. C. Kuiry, L. Bracho, “Effect of Long Term-High Temperature Oxidation in Oxide Scale Surface Chemistry in INCONEL-738LC Superalloy”, 2001, Oxidation of Metals Vol. 57, Nos 3/4, 297-322, 2002.

[Pyramid Gold Nanoparticles] [Monodisperse Nanoceramics]