Forsterite-containing parts for air heaters of blast furnaces

Results of a detailed investigation of the properties of forsterite-containing refractory parts as applied to the service conditions of air-heater checkerwork in blast furnaces are presented. An experimental industrial batch of forsterite-chromite hexagonal checkerwork parts was prepared. The results of their service in an air heater are described.Translated from Ogneupory, No. 8, pp. 29–31, August, 1995.     

Effect of the firing medium and other technological parameters on the properties and phase composition of dinas articles on dry mineralizers

The effect of the gaseous firing medium and other technological factors (grain composition of the charge, pressing pressure, temperature and time of the hold at the final firing temperature) on the properties of dinas and the degree of transformation of silica in it is investigated. On the basis of results of a comparative analysis of the phase compositions and properties of specimens the following parameters are recommended as optimum technological parameters for fabricating dinas on dry mineralizers that provide high operating characteristics for the articles: the maximum grain size of quartzite is 2 mm, the pressing pressure is at least 50 MPa, the firing temperature is 1420°C, the duration of the hold is 44 h. Petrographic and x-ray analyses are used to show the preferableness of firing dinas in a reducing medium, which promotes a fuller transformation of quartz in the dinas and provides high operating properties for the articles.Translated from Ogneupory i Tekhnicheskaya Keramika, No. 6, pp. 14–17, June, 1996.The work has been done in collaboration with L. M. Khvostishkova. The physicochemical properties of the specimens were investigated in specialized laboratories of the Ukrainian Research Institute of Refractories.     

Synthesis and electrochemical performance of doped LiCoO2 materials

Layered intercalation compounds LiM_0.02Co_0.98O₂ (M = Mo⁶⁺, V⁵⁺, Zr⁴⁺) have been prepared using a simple solid-state method. Morphological and structural characterization of the synthesized powders is reported along with their electrochemical performance when used as the active material in a lithium half-cell. Synchrotron X-ray diffraction patterns suggest a single phase HT-LiCoO₂ that is isostructural to α-NaFeO₂ cannot be formed by aliovalent doping with Mo, V, and Zr. Scanning electron images show that particles are well-crystallized with a size distribution in the range of 1–5 μm. Charge–discharge cycling of the cells indicated first cycle irreversible capacity loss in order of increasing magnitude was Zr (15 mAh g⁻¹), Mo (22 mAh g⁻¹), and V (45 mAh g⁻¹). Prolonged cycling the Mo-doped cell produced the best performance of all dopants with a stable reversible capacity of 120 mAh g⁻¹ after 30 cycles, but was inferior to that of pure LiCoO₂.     

Cathodoluminescence of TiO2 Films Formed by Molecular Layer Deposition

Technical Physics Letters - Use of the method of local cathodoluminescence in Si–TiO2 and Si–SiO2–TiO2 structures helps to elucidate the nature of centers influencing the...     

Deaggregation of nanodiamond powders using salt- and sugar-assisted milling

Diamond particles of 5-10 nm in size can be produced in large quantities by denonating oxygen-lean explosives in a closed chamber. They have numerous useful properties and are used in applications ranging from lubricants to drug delivery. Aggregation of diamond nanoparticles is limiting wider use of this important carbon nanomaterial because most applications require single separated particles. We demonstrate that dry media assisted attrition milling is a simple, inexpensive, and efficient alternative to the current ways of deaggregating of nanodiamond. This technique uses water-soluble nontoxic and noncontaminating crystalline compounds, such as sodium chloride or sucrose. When milling is complete, the media can be easily removed from the product by water rinsing, which provides an advantage when compared to milling with ceramic microbeads. Using the dry media assisted milling with subsequent pH adjustment, it is possible to produce stable aqueous nanodiamond colloidal solutions with particles <10 nm in diameter, which corresponds to 1-2 primary nanodiamond particles. The study of milling kinetics and the characterization of the produced nanodiamond colloids led us to conclude that aggregates of less than 200 nm in diameter, observed at the tail of the pore size distribution of milled nanodiamond, are loosely bonded and rather dynamic in nature. Color change observed in ND colloids upon shifting their pH toward the basic end allowed us to demonstrate that the coloration comes from the light interaction with colloidal particles and not from an increase in nondiamond carbon content.     

Charge properties of aluminum oxide layers synthesized by molecular layering

An investigation was made of the charge and conducting properties of layers of insulator obtained by molecular layering in Si-Al₂O₃-Al structures. No charge trapping in the insulator is observed at 77 K when depleting voltages are applied to the structure. Pis’ma Zh. Tekh. Fiz. 24, 58–63 (July 12, 1998)     

Effect of residual air pressure on the long-time strength of low-carbon steel at elevated temperatures

The effect of vacuum in the range 10^–3-10^–6 torr on the long-time strength of steel 08kp for a test base of 500 hr was studied. It was shown that increasing the residual air pressure produces a considerable increase in the long-time strength of the steel studied of 400° C, the effect becoming less pronounced when the test temperature is raised to 800°C.