Our present work presents a direct association of the observed loss of shear strength in boron carbide under plane shock wave compression to amorphization in boron carbide under triaxial stress compression. This evidence is obtained from in-situ measurement of Raman, and infrared vibrational spectra of boron carbide confined in a Diamond Anvil Cell (DAC) under hydrostatic and non-hydrostatic pr...

Carbide composites are materials based on the carbide phases of the refractory or high melting temperature metals. The hard carbide phase (WC, TiC) is usually embedded into soft matrix – pure metals (Fe, Co, Mo, Ni and others) or their combinations. The hard phase supports high hardness and strength of the carbide composites, while matrix is needed for toughness and plastic properties. The ordi...

The inferred crystallographic class of circumstellar silicon carbide based on astronomical infrared spectra is controversial. We have directly determined the polytype distribution of circumstellar SiC from transmission electron microscopy of presolar silicon carbide from the Murchison carbonaceous meteorite. Only two polytypes (of a possible several hundred) were observed: cubic 3C and hexagona...

Nanocomposites films of (polymer blend-ceramics) were prepared from (PVA-PAA) blend and (PVA-PAA) blend doped with niobium carbide nanoparticles for humidity sensors have low cost, easy fabrication, high sensitivity, lightweight and high corrosion resistance. The structural, electrical and optical properties of (PVA-PAA-NbC) nanocomposites have been studied. The D.C electrical properties of (PV...

Element 73 was first extracted from mineral samples and described in 1802 by the Swedish chemist Anders Ekeberg. He chose the name tantalum because “when placed in the midst of acids it is incapable of taking any of them up and saturating itself with them”, in a manner reminiscent of the Greek mythological king Tantalus (pictured) who couldn’t eat or drink anything despite being surrounded by f...

DIS. CHEST, VOL. 56, NO. 1, JULY 1969 FIGURE 3 (upper). Histologic section from right lower lobe of an animal sacrificed immediately after hronchography. Tantalum particles are seen in the lumen of the secondary bronchus. FIGURE 4 (lower). This histologic section from the right lower lobe of a dog sacrificed 24 hours after tantalum bronchography shows no evidence of the heavy metal in the airwa...

The microstructure of the hypereutectic Fe-Cr-C alloy is observed by optical microscopy (OM). The initial growth morphology, the crystallographic structure, the semi-molten morphology and the stacking faults of the primary M7C3 carbide are observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The in-suit growth process of the primary M7C3 carbide was observe...

To develop an effective process for tantalum powder production, a new preform reduction process (PRP) based on the magnesiothermic reduction of feed preform containing tantalum oxide (Ta2O5) was investigated. The feed preformwas fabricated from slurry, which was made by mixing Ta2O5 powder, flux (e.g., CaCl2), and binder. Various compositions of preform in the form of plates were prepared using...