We investigated formation of carbon nanofibers grown by chemical deposition (CVD) method using an acetylenehydrogen mixture on the surface of micron-sized aluminum powder particles. To obtain uniform distribution of the carbon nanostructures on the particles we deposited nickel catalyst on the surface by spraying from the aqueous solution of nickel nitrate. It was found that increasing the time of the synthesis lowers the rate of growth of carbon nanostructures due to the deactivation of the catalyst. The Raman spectroscopy measurements confirm the presence of disordered carbon corresponding to CNFs in the specimen. X-ray photoelectron spectroscopy showed the presence of aluminum carbide in the hot pressed samples. An aluminum composite material prepared using 1 wt.% CNFs obtained by uniaxial cold pressing and sintering showed 30 % increase in the hardness compared to pure aluminum, whereas the composites prepared by hot pressing showed 80 % increase in the hardness. Composite materials have satisfactory ductility. Thus, the aluminum based material reinforced with carbon nanostructures should be appropriate for creating high-strength and light compacts for aerospace and automotive applications and power engineering.

An equation for precision fitting of the temperature dependence of density of any substance in the entire temperature range of its liquid state and an equation for the prediction of the coefficient of thermal expansion, derived from this dependence, was considered. Constants of the equation for 50 liquids were tabulated.The main applied importance of an equation for precision fitting of the temperature dependence of the density or specific volume of liquids is connected with its use for the prediction of thermal expansion coefficients as functions of temperature, which are required for various process calculations.The following equation is used today for precision fitting of the specific volume of liquids [1, 2]:where a, b, and c are experimental coefficients given in reference literature for various liquids with indication of the temperature range of the equation applicability; V 0 is the specific volume at t = 0oC; V, specific volume at a current temperature; and t, current temperature (oC).Various methods for the prediction of thermal expansion coefficients using Eq. (1) are given in [3,4]. It should be noted that these methods are too cumbersome, which does not count in favor of the prediction accuracy. By definition, the thermal expansion coefficient is(2) V dt Hence, it follows from Eq. (1) with a mathematical exactitude that the thermal expansion coefficient is a + 2bt + 3ct 2 b = ÄÄÄÄÄÄÄÄÄÄÄÄÄ.(3) 1 + at + 2bt 2 + ct 3The basic disadvantage of Eqs. (1) and (3) is their applicability in rather narrow temperature ranges. For example, the following ranges of the applicability of Eq. (1) are suggested in [1, 2]: for water, t = 0333; for sulfuric acid, 0 330; for isopentane, 0 327, and for methyl formate, 0 310oC. Furthermore, it is assumed that Eq. 1 is applicable in the vicinity of t = 0oC. Therefore, Eq. (1) basically is unsuitable for condensed gases, molten metals, and also organic and inorganic substances with high melting points.Here we suggest Eq. (4) for precision fitting of the temperature dependence of density of any substances on the saturation line within the entire temperature range of their liquid state:where r cr is the density under critical conditions (kg m 33 ); q = t cr 3 t = T cr 3 T, temperature measured from the critical point (K); t and T, current temperature (oC and K); t cr and T cr , critical temperature

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The possibility of fabricating 'aluminum -carbon nanofibers' compact materials by hot pressing at a pressure of 5 GPa and a temperature of 480 -980°C is studied. It is shown that aluminum carbide forms in the case of hot pressing above 720°C. The hardness of the hot-pressed aluminum -carbon nanofibers' composite material is 80% higher than that of pure aluminum at a satisfactory ductility.