A B C D E F G H I J K L M N O P Q R S T U V W X Y Z All
Chaudhuri, Mahua Ghosh
- Synthesis and Characterization of Silicon Nitride-Aluminium Nitride Nanocomposite Through Sol-gel Route
Authors
1 School of Materials Science & Nanotechnology, Jadavpur University, IN
Source
Indian Science Cruiser, Vol 29, No 6 (2015), Pagination: 20-24Abstract
Nanostructured Si3N1/AIN has been prepared by carbothermal reduction followed by nitridation of silica -alumina gel over a temperature range of 1200 -- 1350°C and time period of 30 minutes to 3 hours in nitrogen atmosphere. Before heat treatment the gel is repeatedly evacuated and purged with ammonia. The nanopores of the gel are filled with ammonia which acts as a source of in situ nitrogen at heat treatment temperature. Dextrose also decomposes during reduction and generates ultra fine carbon. This carbon as well as hydrogen from the cracking of ammonia is not sufficient to create the extremely low partial pressure of oxygen required for the stabilization of Si3N1 and AIN. So the sample is heat treated in charcoal boat in nitrogen atmosphere to achieve that extremely low partial pressure of oxygen. The material has been characterized through XRD, SEM and EDX, Si3N1, nanowires formed by this process areof 135nm-175nm in diameter and several micron meters in length. On the other hand, the obtained particle size of AIN is in the range of 12nm to 28nm.
Keywords
Sol-Gel, Cogelling, Nitridation, Nanowires.- An Overview of Nanotsructured Materials
Authors
1 School of Materials Science & Nanotechnology, Jadavpur University, Kolkata, IN
Source
Indian Science Cruiser, Vol 33, No 4 (2019), Pagination: 15-17Abstract
Nanostructured materials are polycrystalline fine sized materials having size up to 100 nm at least in one dimension. Due to their extremely fine grain structure, the grain boundary volume fraction is much higher compared to coarse grain materials. Moreover, the atomic density along the grain boundary region is also much less. These lead to attractive properties of the nanostructured materials, for example improved mechanical properties, diffusivity, solid solubility etc.Keywords
Nanostructured Materials, Mechanical Properties, Grain Size.References
- Anantharaman T. R. and Suryanarayanan, C. (1987) : Rapidly solidified metals: A Technological Overview. Trans Tech Publ.
- Koch, C. C. (1991) : Processing of metals and alloys, Vol. 15, Materials science and technology.
- Bickerdike, R. L., Clark, D., Easterbrook, J. N., Huhges, G., Mair, W. N., Partridge, P. G. and Ranson, H. C. (1984-85) : Int. J. Rapid solidification.
- Gleiter, H. (1989) : Nanocrystalline materials. Progress in Materials Science, Vol. 33, Issue 4 Pages 223-315
- Suryanarayana, C. (1994) : Structure and properties of nanocrystalline materials, Bull. Mater.Sci. 17:307
- Suryanarayana, C. Froes, Metall, F.H. (1992) : Trans. A23 1071– 1081G. Eason, B. Noble, and I.N. Sneddon, “On certain integrals of Lipschitz-Hankel type involving products of Bessel functions,” Phil. Trans. Roy. Soc. London, vol. A247, pp. 529-551, April 1955.
- Hall E O (1951) : The Deformation and Ageing of Mild Steel: III Discussion of Results. Proceedings of the Physical Society (London). Section B, Volume 64, Number 9, 747
- Petch, N. J. (1953) : The Cleavage Strength of Polycrystals. Journal of the Iron and Steel Institute, Vol. 174, pp. 25-28.
- Coble R L (1963) : A Model for Boundary Diffusion Controlled Creep in Polycrystalline Materials. Journal of Applied Physics 34, 1679 doi: http://dx.doi.org/10.1063/1.1702656.