The ablation material used during the National Ignition Campaign, a glowdischarge polymer (GDP), does not couple as efficiently as simulations indicated to the multipleshock inducing radiation drive environment created by laser power profile [1]. We investigate the performance of two other ablators, boron carbide (B4C) and high-density carbon (HDC) and compare with GDP under the same hohlraum c...

This thesis is a theoretical study of configurational disorder in icosahedral boronrich solids, in particular boron carbide, including also the development of a methodological framework for treating configurational disorder in such materials, namely superatom-special quasirandom structure (SA-SQS). In terms of its practical implementations, the SA-SQS method is demonstrated to be capable of eff...

Composite material is a combination of two or more materials having compositional variations and depicting properties distinctively different from those of the individual materials of the composite. A composite mixture having more than one fiber is known as hybrid composite During the past decade, considerable research effort has been directed towards the development of in situ Metal Matrices h...

The improvement of titanium diboride (TiB2) coatings over the molybdenum substrate was investigated by comparing the electrochemical techniques of continuous current plating (CCP) and periodically interrupted current (PIC). The solvent used was a eutectic Flinak mixture (LiF–NaF– KF, 46.5:11.5:42molar ratio) with solutes K2TiF6 andKBF4 with the electrochemically-active components in themolar ra...

Superhard substances are those a hardness above 20 GPa, i.e. higher than that of corundum (Kislii et al.,1988) or with a Vickers hardness Hv exceeding 40 GPa (Sologenko&Gregorianz, 2005). The ten utmost non-metal substances and refractory compounds form a "hardness pyramid" (Kislii et al.,1988) diamond being on top, followed by cubic-boron nitride and boron carbide. Metal-like ones form a simil...

X-ray optical elements are required for beam transport at the current and upcoming free-electron lasers and synchrotron sources. An X-ray mirror is a combination of a substrate and a coating. The demand for large mirrors with single layers consisting of light or heavy elements has increased during the last few decades; surface finishing technology is currently able to process mirror lengths up ...

Ultrahigh temperature ceramics (UHTCs) such as diborides of zirconium, hafnium tantalum and their composites are considered to be the candidate materials for thermal protection systems of hypersonic vehicles due to their exceptional combination of physical, chemical and mechanical properties. A composite of ZrB2-TiB2 is expected to have better properties. In this study, an attempt has been made...

Abstract Directionally solidified B4C–NbB2-SiC ternary composites were prepared by a floating zone method based on crucible-free melting of compacted powders. The eutectic composition B4C–15NbB2–35SiC (mol.%) was characterized boron carbide matrix, directionally reinforced lamella-type NbB2 and SiC phases. inclusions about 1−2 μm in thickness uniformly dispersed B4C matrix B4C–NbB2–SiC composit...