http://localhost:8080/xmlui/handle/123456789/218 2026-04-26T08:24:50Z 2026-04-26T08:24:50Z Pandey, Ajoy Kumar Biswas, Koushik http://localhost:8080/xmlui/handle/123456789/3209 2025-02-06T09:55:42Z 2014-01-01T00:00:00Z

Title: In vitro cytocompatibility, ageing and wear behavior of ceria stabilized zirconia bioceramic Authors: Pandey, Ajoy Kumar; Biswas, Koushik Abstract: Nano sized ceria stabilized zirconia (CSZ) powders were synthesized by co-precipitation method and then sintered conventionally to near full density. Ageing stability of developed materials was predicted through in vitro hydrothermal treatment in the presence of simulated body fluid (SBF). Fretting wear test at different loads was carried out using balls on flat geometry at different intervals of hydrothermal treatment to observe the effects of surface ageing on wear properties. Wear volume, specific wear rate and wear depth were estimated through 3D profile scan of the worn out surface by a surface profiler and it was found that the developed material became more wear resistant with the increase in hydrothermal treatment duration. XRD analysis and hardness study suggest that formation of orthorhombic zirconia during hydrothermal treatment improves the surface hardness (from 946786 HV20 to 964739 HV20 after 100 h of hydrothermal treatment) which in turn enhances wear resistance. In vitro cytocompatibility of the developed materials was inferred through the formation of hydroxyapatite-like layer on the surface of the material when soaked in SBF at 37.5 1C. Cytocompatibility was further ensured by studding attachment of multilayered human osteoblast cells (MG63) on the surface during cell culture. Description: NITW

2014-01-01T00:00:00Z Kumar, Shankar Sairam, K. Sonber, J.K. Murthy, T.S.R.Ch. Reddy, Vidhyasagar Rao, G.V.S. Nageswara Rao, T. Srinivasa http://localhost:8080/xmlui/handle/123456789/3112 2025-02-05T05:23:09Z 2014-01-01T00:00:00Z

Title: Hot-pressing of MoSi2 reinforced B4C composites Authors: Kumar, Shankar; Sairam, K.; Sonber, J.K.; Murthy, T.S.R.Ch.; Reddy, Vidhyasagar; Rao, G.V.S. Nageswara; Rao, T. Srinivasa Abstract: This paper reports on the effect of molybdenum disilicide (MoSi2) addition on the densification and mechanical properties of boron carbide (B4C). Molybdenum disilicide powder (10 and 30 wt%) was added to boron carbide powder and consolidated by hot pressing at various temperatures (1700–1900 1C) and pressures (30–50 MPa) in 0.001 Pa vacuum. MoSi2 was found to react with B4C and form reaction products SiC, MoB2 and Mo2B5. Slight improvement in density was observed with respect to MoSi2 addition. High density compact has been obtained with 30 wt% MoSi2 at 1900 1C under a pressure of 50 MPa. The hardness, elastic modulus and fracture toughness of high dense B4Cþ30 wt% MoSi2 compact was found to be 35.1 GPa, 555 GPa and 4.8 MPa m1/2 respectively. Description: NITW

2014-01-01T00:00:00Z Golla, Brahma Raju Ko, Jae Woong Kim, Jin-Myung Kim, Hai-Doo http://localhost:8080/xmlui/handle/123456789/3085 2025-02-04T06:03:10Z 2014-01-01T00:00:00Z

Title: Effect of particle size and oxygen content of Si on processing, microstructure and thermal conductivity of sintered reaction bonded Si 3N4 Authors: Golla, Brahma Raju; Ko, Jae Woong; Kim, Jin-Myung; Kim, Hai-Doo Abstract: In the ceramic processing, use of the fine powders is more desirable in order to enhance densification and eventually the properties of ceramics. However, during the particle size reduction (using ball milling), the powders are also prone to surface oxidation. In this perspective, the present contribution systematically investigates the influence of Si particle size and its oxygen content on nitridation, densification, microstructure and thermal conductivity of sintered reaction bonded Si3N4 (SRBSN) mixed with 3.5% Y2O31.5% MgO (sintering additive). Despite it’s relatively low density, the SRBSN sample with Si as received powders exhibited high thermal conductivity when compared to SRBSN with planetary ball milled samples. A maximum thermal conductivity of 90 W/mK was measured for the SRBSN sample (using high purity Si as received powders) after gas pressure sintering at 1950 C for shorter sintering time of 3 h. It is a promising result as far as the industrial applications are concerned. Normally in the literature very high sintering temperatures and extensive sintering times were reportedly used for obtaining high thermal conductivity of Si3N4 ceramics. In the present work, the improvement in thermal conductivity of the SRBSN with Sias received powders can be attributed to its coarse grain microstructure, large elongated bSi3N4 grains, relatively small amount of grain boundary phase (mainly because of low amount of oxygen in starting raw Si powders when compared to Si planetary ball milled powders) and large phonon scattering distance. As far as the thermal transport properties are concerned, the present research reveals that the use of Si powders with moderate particle size and low amount of oxygen is beneficial to improve the thermal conductivity of SRBSN. Description: NITW

2014-01-01T00:00:00Z Gadakary, Saikumar Khanra, Asit K. Veerabau, R. http://localhost:8080/xmlui/handle/123456789/3073 2025-02-04T05:06:32Z 2014-01-01T00:00:00Z

Title: Production of nanocrystalline TiB2powder through self-propagating high temperature synthesis (SHS) of TiO2-H3BO3-Mg mixture Authors: Gadakary, Saikumar; Khanra, Asit K.; Veerabau, R. Abstract: Nanocrystalline TiB2 powders are produced through self-propagating high temperature synthesis (SHS) technique by igniting the stoichiometric mixture of titanium oxide (TiO2), boric acid (H3BO3) and magnesium (Mg) powder. Different percentages of NaCl are added to the mixture as SHS diluent in order to control the particle size of the TiB2. The synthesised and purified powder is characterised by X-ray diffraction and electron microscopes respectively. The SEM images show the presence of agglomeration of fine spherical particles. The TEM images reveal the formation of nanocrystalline TiB2 particles. The particle size is found to decrease with the addition of NaCl. The TEMimagesreveal the presence of crystallographic defects in the powder. In order to find out the reaction mechanism of TiO2–H3BO3–Mg system, the synthesis of TiO2–Mg and H3BO3–Mg mixtures is performed in inert atmosphere and phase analysis of TiO2–Mg and H3BO3–Mg mixtures reveal the reaction mechanism. Description: NITW

2014-01-01T00:00:00Z