INFLUENCE OF PHOSPHORUS IMPURITY ON THE STRUCTURE AND NATURE OF THE DESTRUCTION OF THE GENUINE DAMASCUS STEEL

It is established that the ancient knife blade belongs to the Eastern group of Indo-Persian steel type genuine Damascus steel with a pattern of "Kara-Taban", which literally means blackshiny. The methods of spectral, x-ray phase and optical analysis show that the genuine Damascus steel is a high-purity non-alloy high-carbon steel with a high content of phosphorus. It is revealed that phosphorus, having a high segregation coefficient of impurity contributes to the process of segregation of carbon in the process of crystallization of crucible ingots. The main physical and chemical factors influencing morphology of structure formation of genuine Damascus steel are revealed. It is established the relationship between the structure and the nature of the destruction of the genuine Damascus steel under impact load.

Influence of Carbon Nanoparticle Addition (and Impurities) on Selective Laser Melting of Pure Copper

The addition of 0.1 wt % carbon nanoparticles significantly improved the optical absorption and flowability of gas-atomized copper powder. This facilitated selective laser melting (SLM) by reducing the required laser energy density to obtain 98% dense parts. Moreover, the carbon addition led to an in situ de-oxidation of the copper parts during the SLM process. The properties of the as-built copper parts were limited to a tensile strength of 125 MPa, a ductility of 3%, and an electrical conductivity of 22.7 × 106 S/m, despite the advantageous effect of carbon on the powder characteristics and SLM behavior. The modest mechanical properties were associated with the segregation of carbon nanoparticles and other impurities, such as phosphorus and oxygen along grain boundaries of epitaxially grown grains. Whereas, the low electrical conductivity was mainly attributed to the phosphorus impurity in solid-solution with copper.

Effect of Thermal Annealings and Cooling Methods on Electrophysical Parameters of n Si Doped with Phosphorus Impurity Via the Melt and by Nuclear Transmutation Technique

The effect of the different regimes of heat treatment on the kinetics of electronic processes in silicon crystals doped with phosphorus impurity via the melt and by nuclear transmutation technique. The most significant influence of cooling under intermediate value of cooling rate (ucl » 15 оС/min) after high-temperature annealing on the main electrophysical parameters of the transmutation-doped n‑Si áPñ crystals was established. Features of changes of the anisotropy parameters of mobility and thermal electromotive force measured on silicon crystals of different doping techniques both in the initial state, and after high-temperature annealing when using different cooling rates, were found and explained.

Phosphorus Oxide Assisted n-type Dopant Diffusion in 4H-Silicon Carbide

Phosphorus is an important n-type dopant for both silicon and silicon carbide. Although solid-state diffusion of phosphorus in silicon has been well documented and experimentally proven, not much is known about phosphorus solid-state diffusion in silicon carbide, especially at lower temperatures. A convenient source of phosphorus for solid-state diffusion in silicon carbide is phosphorus oxide. The possibility of using phosphorus oxide as a dopant source for silicon carbide is investigated by considering the probable reactions between silicon carbide and phosphorus oxide at temperatures below 1700 K using published thermodynamic data. By considering the standard free energies of reactions, it can be shown that phosphorus can be introduced in silicon carbide at temperatures below 1700 K using phosphorus oxide. A successful development of low temperature dopant incorporation in silicon carbide would reduce the need for high temperature processes and prevent process-induced thermal degradation of critical device structures such as the oxide-semiconductor interface. Experimental results showing phosphorus impurity incorporation and activation in 4H-SiC are presented.