L N Satapathy
Articles written in Bulletin of Materials Science
Volume 25 Issue 6 November 2002 pp 569-572
Boric acid has been added in 0.1–0.6% range for studying the densification characteristics of solid state sintered barium hexaferrite. Sintering studies have been carried out at three different temperatures. Physical properties like density and porosity have been studied for all compositions. The phase identification and microstructural investigation on the fractured surface have been carried out to understand the effect of sintering aid on the densification characteristics.
Volume 28 Issue 3 June 2005 pp 281-285 Mechanical Properties
Small levels of various dopants have a significant effect on creep in polycrystalline alumina. While most previous studies have examined the effect of ionic size, the influence of valency of dopants on creep has not yet been completely characterized. The present detailed experimental study, utilizing magnesia and zirconia with a similar ionic size, demonstrates that the ionic valency of dopants also plays a crucial role in creep since magnesia does not significantly alter creep whereas zirconia retards creep substantially. Magnesia doped alumina deforms by Coble diffusion creep whereas zirconia doped alumina deforms by an interface controlled diffusion creep process.
Volume 33 Issue 3 June 2010 pp 251-255 Polymers
Polycrystalline diamond coatings are grown on Si (100) substrate by hot filament CVD technique. We investigate here the effect of substrate roughening on the substrate temperature and methane concentration required to maintain high quality, high growth rate and faceted morphology of the diamond coatings. It has been shown that as we increase the substrate roughness from 0.05 𝜇m to 0.91 𝜇m (centre line average or CLA) there is enhancement in deposited film quality (Raman peak intensity ratio of 𝑠𝑝3 to non-𝑠𝑝3 content increases from 1.65 to 7.13) and the substrate temperature can be brought down to 640°C without any additional substrate heating. The coatings grown at adverse conditions for 𝑠𝑝3 deposition has cauliflower morphology with nanocrystalline grains and coatings grown under favourable 𝑠𝑝3 condition gives clear faceted grains.
Volume 42 | Issue 5
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