Vol 73, No 1-2 (2016)

The strength of glass can be increased by modifying the surface layer. The following are examined: graded glass in which the glass strength in increased by means of the CLTE differential over the glass thickness; ion bombardment at room temperature where large atoms are embedded (implanted) in the glass in a strong electromagnetic field; protective coatings (temporary and permanent); and, chemical strengthening. These methods make it possible to increase glass strength by increasing the surface strength of the glass without changing the bulk strength.

A method of obtaining optical fiber with a refractive-reflective cladding formed in the process of extrusion from a single-spinneret vessel as a result of the interaction between the spinneret material and the glass melt of the light-guiding fiber core. Using glass with highly volatile components for the light-guiding core in order to best match the compositions of the initial glass and the light-guiding core the method affords the creation of a polycrystalline or glassy layer with the same composition along the surface during the extrusion process.

The possibility of using iron-ore enrichment tailings in the production of ceramic articles is investigated. The compositions and properties of ceramic bodies and the process parameters for manufacturing articles are presented. To increase product quality nepheline concentrate is used as an alkali-containing additive.

The effect of nutrient liquids with the bacteria Acinetobactre johnsii str. J221 and Pseudomonas aeruginosa str. G.d. on the rheological properties of porcelain slip is studied. The surface activity of the nutrient liquid promotes a reduction of the fluidity and thixotropic hardening of porcelain slip. The mass increase of the casting upon pouring is due to the hydrophobization of the surface of the slip particles. The thickening of the porcelain slip is interrelated with the change in the redox state of the medium from weakly to strongly basic, favorable for the development of an aborigennic community of anaerobic microorganisms.

The role of technological trends in the technologies used to increase product quality in real ceramic production is examined for the example of a unified principle of optimization. It is shown that the uniformity of the final microstructure of a polycrystalline material depends on the probability of reaching the requirements imposed by the principle of optimization on process stages such as synthesis and the formation and sintering of blanks. Ways to increase the quality and profitability of the manufacture of ceramic products intended for use under extreme conditions are examined for the example of the components of nuclear fuel.

Flat membrane contactors comprising ceramic disk microfiltration membranes with a deposited layer of Co₃O₄ are obtained. The characteristics, such as the thickness of the layer and the pore-size distribution, are determined and the specific surface of the substrate and the deposited layer of Co₃O₄ are determined. It is shown that the membrane contactors obtained are suitable for liquid-phase catalytic oxidation of phenols under soft conditions, including in waste waters.

Ceramic based on calcium phosphates is obtained from powders synthesized from water solutions of calcium nitrate, ammonium hydrophosphate, and ammonium pyrophosphate as well as from a mixed-anionic solution containing simultaneously ammonium pyro- and orthophosphate in the molar ratio (NH₄)₂HPO₄/(NH₄)₄P₂O₇ = 1. The ceramic obtained contains biocompatible bioresorbable phases and can be used to make implants used in regenerative methods for the treatment of bone tissue defects. This represents the first time synthesis from mixed-anionic solutions is used to obtain powders of calcium phosphates with significant quantities of each anion.

The measurements of the CLTE and relative elongation of two types of borosilicate glasses — LK5 and Borofloat 33 — are analyzed. A TMA7100 thermomechanical analyzer is used to measure the elongation of glass samples at temperatures from 130 to 800 K (−143 to +526°C). The relative error of indirect measurements of the CLTE and the relative thermal elongation of both types of glasses did not exceed ±5 and ±3%, respectively. Polynomial equations for obtaining fits to the measurements as a function of the temperature are presented. The results will facilitate the modeling of the characteristics of the devices which are used in microsystems engineering and fabricated by anodic deposition of silicon on glass; they can also be used to optimize the temperature regime of silicon bonding with glass.

The results of research on the use of sludge produced in the process of purification of drinking water (SPDW), which contains about 68% Fe₂O₃, as an additive in the production effective ceramic articles are presented. SPDW was added in amounts 40 – 60% into the batch for the production of effective ceramic articles; the firing temperature of the ceramic articles was 900, 1000, and 1050°C. The investigations showed that the addition of SPDW affects the properties of ceramic samples as follows: it lowers the density, strength in compression, and thermal conductivity and increases porosity. SPDW is a natural pigment that imparts a darker red color to the ceramic.

Domestic commercially accessible α-Al₂O₃ powders are examined and evaluated for use as raw material for the production of high-strength ceramic. Additional chemical purification and mechanical processing of GRT alumina make it possible to improve the ceramic properties of the material. In terms of density and microhardness the ceramic obtained from fine-crystalline alumina produced by Nanokompozit JSC surpasses all materials examined, including ceramic obtained from Almatis-1200 alumina.