Ashok Ranjan

Mechanical, tribological and thermal properties of hot pressed ZrB2–SiC composite with SiC of different morphology

Abstract ZrB2–SiC composites were prepared by hot pressing with different sources of SiC to study the effect of SiC with different morphology on densification, microstructure, phase composition and mechanical properties like hardness, fracture toughness and tribological properties (namely, scratch resistance, wear parameters) and thermal behaviour of the composites. Three different ZrB2–SiC composites, i.e. ZrB2–SiCP (polycarbosilane derived SiC), ZrB2–SiCC (SiC from CUMI, India) and ZrB2–SiCH (SiC from H. C. Starck, Germany), were studied. It is found that ZrB2–SiCC composite shows highest hardness (19·13 GPa) and fracture toughness (5·30 MPa m1/2 at 1 kgf load) in comparison with other composites. Interconnected network, better contiguity between grains of ZrB2–SiC composites and impurity content in starting powders can play significant roles for achieving high mechanical, tribological and thermal properties of the composites. Coefficient of friction and wear parameters of all ZrB2–SiC composites are very low, and thermal conductivity of ZrB2–SiC composites varied from 52·71 to 65·53 W (m K)−1 (ZrB2–SiCP), 54·30 to 71·55 W (m K)−1 (ZrB2–SiCC) and 64·25 to 88·02 W (m K)−1 (ZrB2–SiCH), respectively and also calculate the interfacial resistance of all the composites.

A novel carbon rich crystalline (C) SiC-Si(n) interface using liquid polycarbosilane as a precursor - a unique Schottky junction

This paper presents a novel rectifying interface material using carbon rich crystalline (C)-SiC and n-type Si by a modified CVD technique, using liquid polycarbosilane as a precursor at 900 °C. The equilibrium band diagram and Fermi level alignment was explained using Poissons model and the depletion approximation. The junction capacitance, depletion width and saturation current were evaluated and further discussed from the perspective of temperature dependency. The junction was found to be Schottky in nature, with a large breakdown voltage of 69 V and low space charge. This type of junction material, having good mechanical strength, is promising for high temperature and high power applications.

Factorial design, processing, characterization and microstructure analysis of PIP-based C/SiC composites

Polymer impregnation and pyrolysis (PIP) process-based C/SiC composites are fabricated using the in-house synthesized methyl-polycarbosilane (PCS). Two-level factorial design matrix is employed to carry out experiments to study the effect of four factors on flexural strength of the composite. Total sixteen sets of composite samples are fabricated. Response table, normal probability plot, ANOVA and regression analysis are carried out to determine the statistical significant factors. Composite density (

Study of electrospun polycarbosilane (PCS) nanofibrous web by needle-less technique

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Mechanical and tribological properties of silicon carbide coating on Inconel alloy from liquid pre-ceramic precursor

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Microscopic, mechanical and thermal properties of spark plasma sintered ZrB2 based composite containing polycarbosilane derived SiC

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