A microstructural study was conducted on 15 cobalt-chromium-nickel alloys of the basic composition 40 Co-30 Ni-30 Cr. The alloys were strengthened by the addition of tantalum and tantalum-rich regions were found at the interdendritic spaces. The increase in Ta concentration caused a decrease in the concentration of the a phase and an increase in the amounts of the a phase. Excessive amounts of ...

Hafnium oxide mixed tantalum oxide (HTO) and Zirconium oxide mixed tantalum oxide (ZTO) layers were deposited on chemically cleaned p-Si substrate using RF magnetron sputtering technique. The oxide/Si stacks were annealed in oxygen for 30 minutes at 400 °C as on initial investigation. Both composition and structural properties were absolutely interesting to move further for electrical measureme...

Fine, monophasic silicon carbide powder has been synthesized by direct solid-state reaction of its constituents namely silicon and carbon in a 2.45 GHz microwave field. Optimum parameters for the silicon carbide phase formation have been determined by varying reaction time and reaction temperature. The powders have been characterized for their particle size, surface area, phase composition (X-r...

Boron carbide is one of the lightest and hardest ceramics, but its applications are limited by its poor stability against a partial phase separation into separate boron and carbon. Phase separation is observed under high non-hydrostatic stress (both static and dynamic), resulting in amorphization. The phase separation is thought to occur in just one of the many naturally occurring polytypes in ...

Carbide tungsten cobalt alloys were deformed in compression or in three point bending in a temperature range 1000-1350°C and in a stress domain 30-1000MPa. In these conditions, the stress exponent n of WC-CO alloys is a function of only the cobalt volurnic ratio and tends tow rds n = 1 for pure B carbide. The apparent activation energy is 550 kj mole. T.E.M. investigations on pure carbide defor...

The pressure-induced phase transition in silicon carbide is studied using a constant-pressure ab initio technique. The reversible transition between the zinc-blende structure and the rock-salt structure is successfully reproduced through the simulation. The transformation mechanism at the atomistic level is characterized, and it is found that the transition is based on a tetragonal and an ortho...

Introduction: The development of a self-limiting caries removal technique would be of great clinical importance. Smart bur II is a relatively new bur in the dental market and its manufacturer is claiming that it is the ultimate bur for selective caries removal. Objectives: The aim of this study was to evaluate caries removal time and efficacy of Smart bur II in comparison with conventional carb...

Findings of laser-assisted atom probe tomography experiments on boron carbide elucidate an approach for characterizing the atomic structure and interatomic bonding of molecules associated with extraordinary structural stability. The discovery of crystallographic planes in these boron carbide datasets substantiates that crystallinity is maintained to the point of field evaporation, and character...

This paper investigates the mechanisms of material removal in dynamic friction polishing of polycrystalline diamond composites through the analysis of polishing-produced debris. The specimens used were PCD compacts composed of diamond and silicon carbide. In order to uncover the debris’ structure, high-resolution transmission electron microscopy (HRTEM), electron diffraction and electron energy...