The influence of oxygen concentration on the formation of CuO and Cu2O crystalline phases during the synthesis in the plasma of low pressure arc discharge

Abstract

Abstract. This paper describes the synthesis of copper oxide nanoparticles with different percentages of CuO and Cu 2 O phases. It was achieved by the control of the percentage of oxygen in the gas mixture (N 2 + O 2 ) in a plasma-chemical process of evaporation-condensation by means of low-pressure arc discharge. In all the experiments, the pressure in the plasma-chemical reactor remained constant at 60 Pa. By means of X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR) it was found that the average particle size was 6 nm, and Cu 2 O phase content decreases with increasing oxygen content in the gas mixture. High photocatalytic properties of Cu 2 O powder were shown by the example of the reaction of the methyl orange dye decomposition in water solution. The problems, associated with the performance of this method and the formation of crystalline phases, are discussed.

Production of high-coercivity materials based on BaFe12O19by crystallization of plasma-sputtered powders

“…The process equipment for plasma spraying and rapid quenching is discussed in detail in [11][12][13][14][15][16][17][18][19][20]. For the preparation of barium ferrite, rapidly quenched powders were used with the composition corresponding to the chemical composition of anisotropic magnets (Fe 2 O 3 -3 84.1%, BaO-15.4%, additives of aluminum and boron oxidenot more than 0.5%).…”

Influence of copper nanoparticle film processing temperature on their structure and electrical properties

“…There are different methods for deposition coating based on copper NPs and their subsequent modification. For example, film deposition in vacuum conditions: chemical vapor deposition (CVD) and physical vapor deposition (PVD) [14,15], chemical methods of precipitation from solution (Langmuir-Blodgett technology, application in an electric field, etc.) [16,17] are such methods.…”

“…Depending on this, the conditions for their application and the choice of method can be changed. Thus, it was shown in [14,15] that the growth of the monoclinic phase of CuO begins to predominate over the cubic phase of Cu 2 O with increasing O2 concentration in the gas mixture of the plasma-chemical reactor. For a liquid medium (phase) the change in the degree of oxidation can be carried out by shifting the pH of the subphase [16,17].…”

Формирование структуры и физико-механических свойств квазикристаллического сплава системы Al-Cu-Fe при плазменном напылении

“…Однако во многих слу-чаях, важных для практического применения, требуется нанесение покрытий из квазикристаллического матери-ала толщиной от 100 µm до 1 mm. Наиболее техноло-гичным в этом отношении является способ плазменного напыления, который благодаря высоким температурам плазменной струи (до 10 000 K) позволяет проводить распыление широкого круга материалов, в том числе и тугоплавких соединений [8][9][10][11][12]. Значительные скорости (до 1000 m/s) движения частиц дают возможность осу-ществлять операции как высокоскоростного распыления, так и сверхбыстрой закалки и фиксировать возникаю-щие при этом неравновесные состояния.…”