Search

Quartzite is a mountain igneous sedimentary rock formed by fusion of quartz sand with other minerals. The volume of its consumption is increases constantly. For this reason resolution of the problem of the feasibility of developing a new formation or a new site (lode) of an existing quartzite deposit depends directly on its properties. This is especially true for the use of quartzite in the metal industry where it is exposed to high temperature. As a rule studying properties of quartzite for water absorption, open porosity and apparent density is performed at room temperature. Macro and microstructures are studied before and after calcining at 1450°C using optical microscopes that make it possible to conduct X-ray phase analysis.

We have made investigations of the phase formation and microstructure on the ceramics obtained from a starting nanopowder mixture with the weight ratio ZnO : TiO2 = 4 : 1. Ceramic is obtained at different sintering temperatures, namely, 948, 1223 and 1473 ?. Using the characterization methods of electron microscopy, energy dispersive microanalysis and X-ray diffraction phase analysis it has been shown that the ceramics structure is consisted of two dispersed phases of Zn2TiO4 and ZnO with the grain sizes being in range 0,5-1 ?m. It has been found also that, at ceramic`s sintering temperature of 1223 ?, the solid phase interactions are completed with the structure ZnO : Zn2TiO4 ? 1 : 1,5 phase ratio.

This paper introduces a new concept of coated fine carbides modified by nanoparticles Al2O3, ZrO2 (inhibitors) as the starting method for improved hardmetals. The study involved computational and experimental methods to determine functional relationships between the parameters of microstructure, sizes, volume content of additives of nanoparticles and properties (transverse rupture toughness, hardness, fracture toughness) of the heterophase hardmetal composites. Factors having a positive influence on the structure of hardmetals are the decrease in the average size and contiguity of carbide grains due to SPS-consolidation and ultrasonic activation during mixing. The study of microstructural parameters by scanning electron microscopy in a combination with x-ray phase analysis indicates high statistical homogeneity of the relative distribution of nanoparticles (inhibitors) in the cobalt binder between carbide grains and the formation of nanostructured inclusions in hardmetal composites.

The influence of nanoparticles additives on the hard metals properties has been investigated. Nanoparticles introduced into a binder of average size decrease the metal interlayer and therefore increase the strength of binder and composite as a whole. The reduction of the carbide grain average size was found as well (owing to nanoparticles blocking influence on re-crystallization). Besides, the internal thermotension and adhesion wear decrease at high speed cutting (especially for stainless steel) in comparision with base hard metals. The test results display that the modification through ultrafme particles enables to improve the main properties: wear resistance – 1.6 - 2 - fold; fracture toughness – 1.8 - 2 - fold; transverse rupture toughness - at 25 - 50%; tool life – 1.3 - 4 - fold.

The paper presents the results of experimental investigation of formation microstructure and properties of ultra high molecular weight polyethylene (UHMW-PE), modified by ceramics А12О3 particles by different particle size and method of obtaining.

The laws governing the formation of residual stresses in copper oxide nanoparticles in the process of their direct plasma-chemical synthesis in a low-pressure arc discharge plasma are studied. Correlation dependences of the residual stress and the magnetization of nanoparticles on the pressure of the gas mixture of 10% O 2 + 90% Ar are presented. The problems associated with the bifurcation of the magnetization curves during cooling in zero (ZFC) and non-zero (FC) magnetic field, non-equilibrium behavior, relaxation of magnetization and magnetic viscosity of the obtained CuO nanoparticles are discussed.

Results are presented from a study of the phase composition of spent quartzite lining from a crucible-type industrial frequency induction furnace. The study is performed by the methods of x-ray analysis. The lining that was examined contained quartzite, boric acid, and electrocorundum. Different regions of the lining were identified and their phase composition was determined along with the changes in the lattice parameters of the components of each region’s phases.

The effect of temperature on the change in quartzite crystal lattice interplanar distances of industrial purity (IChT) used in lining induction and crucible furnaces is studied by x-ray-phase analysis (XPA). A regularity is revealed for changes in interplanar distance. A curve is plotted for these changes. The connection of changes in crystal lattice with material properties is determined, affecting induction furnace lining life.