Mechanical activation of the reactive sintering of titanium carbide

This paper describes the mechanical alloying of Ti and C powders by intensive grinding in a planetary mill. The effect of milling conditions and initial composition on the compositional homogeneity and properties of powders and samples consolidated by hot-pressing was studied by x-ray diffraction, scanning electron microscopy, and surface area measurement. The diffraction patterns indicated that a powder mixture ground for 24 hours transforms to TiC after sintering for only one minute at 600°C under a pressure of 3 GPa. Materials Science Instiute, Ukrainian Academy of Sciences, Kiev. Translated from Poroshkovaya Metallurgiya, Nos. 5–6, pp. 32–38, May–June, 1998.     

Thermal conductivity of high-T c crystals: Dependence on magnitude and orientation of magnetic field,and effect of Zn doping

We present precise measurements of in-plane thermal conductivity for superconducting single crystals of YBa₂Cu₃O_7?x (YBCO) withT _c =92 and 60 K, Bi₂Sr₂CaCu₂O₈ (BSCCO), and of Zn-doped YBCO. Magnetization and thermal conductivity data obtained with the same 90-K YBCO crystal demonstrate a close relationship between the magnetic thermal resistivity and the internal magnetic fieldB in a superconductor in the mixed state. For all superconductors studied here, the magnetic thermal resistivity is a sublinear function of magnetic field. The origins of the nonlinearity are discussed. Angular dependences of the magnetic thermal resistivity have been shown to depart from the anisotropic 3D superconductor model and are in quantitative agreement with a quasi-2D model. Implications for spatial modulation of the order parameter are made.     

Effect of chemistry and particle size of cryochemical powders on the properties of humidity sensors

A comparative analysis of various sintered materials based on cryochemical powders was carried out. The electrical resistance of compacts of pure aluminum oxide and its mixtures with CoO, MgO, ZrO₂, and Y₂O₃ were compared with data on the specific surface area, phase composition, and pore size distribution in the sintered ceramics. Conclusions were drawn about the suitability of the materials as humidity sensors. Highest sensitivity was found in sensors based on aluminum—cobalt spinel, and aluminum—magnesium spinel mixed with zirconium oxide. Deceased. Materials Science Institute, Ukrainian Academy of Sciences, Kiev. Translated from Poroshkovaya Metallurgiya, Nos. 3–4(400), pp. 39–43, March–April, 1998.     

Systems for monitoring technological and production processes of commercial enterprises

The problems that arise in comprehensive automation of production are considered. Characteristics are given and examples are provided of intellectual measurement provisions and control, information measurement systems, and software/hardware suites used in enterprises of the chemical, mining, petrochemical, metallurgical, and oil processing industries. A version of implementing a system for production management is demonstrated. __________ Translated from Izmeritel’naya Tekhnika, No. 7. pp. 59–62, July, 2007.     

Effect of Magnetic Abrasive Finishing on the Chemical and Phase Composition of TiC Coatings on VK8 Alloy

Using x-ray diffraction analysis and electron-probe microanalysis, we have studied TiC coatings obtained by chemical vapor deposition, where the base and subsequently the coating have undergone magnetic abrasive finishing. We have found that treating the base before the coating is deposited prevents an η phase (Co₆W₆C) from forming in the surface layer of coated platelets. Magnetic abrasive finishing (MAF) has been found to cause an α → β transition in the cobalt phase.