New filter materials

The possibility of producing reinforced material for filtration made from basalt fibres and different combinations with glass fibres was demonstrated. The technological production parameters were developed and the physicomechanical indexes of the cloth were determined. It was found that cloth made of basalt fibre had the best air permeability, but the processability was worse than for combined and glass cloth. Cloth with a concentration of 50 wt. % basalt and 50 wt. % glass fibres had the optimum physicomechanical properties and best processability.Berdyansk Glass Fibre Plant. Translated from Khimicheskie Volokna, No. 6, pp. 56–57, November–December, 1994.     

Mechanisms of breakdown of the structure of glass cloth during impregnation with polymer binders

The basic sources of worsening of the quality indexes of insulating glass cloth and the requirements for the properties of the cloth and binder during impregnation were determined: short pile, gas inclusions, thermodynamic characteristics of binder and monofilament on the binder—monofilament, binder—air, and air—monofilament interface, internal stresses in the structure of the cloth, weave geometry, and position of monofilaments in the complex fibre.Stekloplastik—Sertifikat Co., Moscow. Translated from Khimicheskie Volokna, No. 3, pp. 43–46, May–June, 1994.     

Controlling the electrical resistance of silicon carbide powders

Conclusions A method is specified for determining the specific electrical resistance of silicon carbide powders; the characteristics of the materials used in the production of silicon carbide electric heaters are determined.It is recommended that the method be introduced at factories which make these heaters for the delivery control of the main raw material — green silicon carbide.Translated from Ogneupory, No. 2, pp. 23–25, February, 1986.     

Thermal conductivity of basalt fiber materials

The thermal conductivity of cloth from vitreous staple fibers from basalt rocks produced by the Asbotermosteklo Plant (Zheleznodorozhnyi) with different densities and fiber diameters is investigated under arbitrary regimes. Recommendations on the use of the cloth for thermal insulation of equipment with operating temperature of up to 700°C are given.Translated from Ogneupory, No. 10, pp. 25 – 26, October, 1995.     

An Unwoven Basalt-Fiber Material for the Encasing of Fibrous Insulation: an Alternative to Glass Cloth

Methods for production of glass and basalt cloth and properties of a cloth produced from continuous basalt fibers are described. The characteristics of glass and basalt cloth are compared     

Advisability of establishing norms for the specific electrical resistance of viscose textile yarns

Conclusions It has been shown that the form of preparation and the amount of it on viscose yarn do not exert an important effect on its specific surface electrical resistance.The specific surface electrical resistance of viscose yarns is considerably below the limiting level of electrical resistance value which ensures normal processing of textile yarns.Translated from Khimicheskie Volokna, No. 2, pp. 39–40, March–April, 1986.     

基于反射裂缝防治的玄武岩经编纤维布阻裂性能研究

针对沥青路面面层出现的轻度反射裂缝问题,为增强防治措施,本文对玄武岩经编纤维布阻裂性能进行了试验研究。通过冲击韧性试验与动态疲劳试验研究了玄武岩经编纤维布和对照土工合成材料(玻纤格栅、聚酯玻纤布)的防反性能,最后对沥青混合料加铺不同土工合成材料后的抗冲击性能与抗疲劳性能进行了相关性分析。研究结果表明:加铺玄武岩经编纤维布,沥青混合料的冲击韧性可提升70%以上;玄武岩经编纤维布在防治裂缝产生与延缓裂缝扩展方面均表现出了优于玻纤格栅和聚酯玻纤布的能力,在沥青混合料中铺设玄武岩经编纤维布可获得最好的疲劳抗裂性能。铺设土工合成材料后,混合料的冲击韧性与其疲劳寿命相关性较好,采用冲击韧性预估沥青混合料加铺土工合成材料后的抗疲劳性能具有可行性。     

Influence of nucleation agents on crystallization and machinability of mica glass–ceramics

Effects of ZrO₂, La₂O₃, CeO₂, Yb₂O₃ and V₂O₅ on the crystallization kinetics, microstructure and mechanical properties of mica glass–ceramics were investigated by the differential scanning calorimetry (DSC), X-ray diffractometry (XRD), scanning electron microscopy (SEM) and microhardness tester. Results show that bulk crystallization can be obtained by introducing proper nucleation agents into the glass. Both Ozawa method and Kissinger method are suitable for analyzing the crystallization kinetics of mica glass–ceramic. The addition of nucleation agents has little influence on the value of n, keeping two-dimensional crystal growth mechanism. ZrO₂ and V₂O₅ are best nucleation agents in mica system. The increase of crystallization temperature is helpful for the increase of aspect ratio, and the microstructure of the glass–ceramics becomes interconnected, which contributes the improvement of the machinability of the glass–ceramics. Microhardness (H_v), cutting energy (μ¹) and machinability parameter (m) can be used for estimating the machinability of mica glass–ceramics.     

Investigating the life of some materials in lead chloride melts

Conclusions We investigated the resistance of a number of materials in lead-chloride melts at 460–800°. We determined the degree of impregnation of mica-sitall, basalt, refractory concrete and chrome-magnesite brick during electrolysis. The results obtained can be used in production, and also for designing electrolyzers for obtaining and refining heavy nonferrous metals from molten electrolytes.Translated from Ogneupory, No. 1, pp. 23–26, January, 1968.     

Preparation and properties of glass–ceramics derived from blast-furnace slag by a ceramic-sintering process

Glass–ceramics were synthesized using ground blast-furnace slag and potash feldspar additives by a conventional ceramic-sintering route. The results show 5 wt% potash feldspar can enhance the sintering properties of blast-furnace slag glass and the results glass–ceramics have desirable mechanical properties. The main crystalline phase of the obtained glass–ceramic is gehlenite (2CaO·Al₂O₃·SiO₂). A high microhardness of 5.2 GPa and a bending strength higher than 85 MPa as well as a water absorption lower than 0.14% were obtained.     

Normalization of specific electrical resistance characteristic of complex acetate yarns

Conclusions It has been shown that, regardless of the type of lubricant or its content on acetate textile yarn, an essentially identical decrease in specific electrical resistance is observed.The specific electrical resistance of acetate yarns which have been treated with lubricants lies in a range which ensures normal processing of such yarns into textile articles.Translated from Khimicheskie Volokna, No. 6, pp. 20–21, November–December, 1989.     

Effect of additions of oligomeric epoxides on the physicochemical properties of cellulose acetates

Conclusions The effect of oligomeric epoxides based on polyethylene oxide and epichlorohydrin, having an epoxy group content of 8–15%, on the physicochemical and structural—mechanical properties of solutions and films of CA has been described.It has been shown that, in the first stages of degradation, the modifiers are effective thermostabilizers (at a content from 0.5 to 10% of the weight of the CA).The devitrification region of the modified specimens is shifted in the low-temperature direction by 5–33°C on increase of the oligomer content from 2 to 15%; the relative elongation rises by a factor of 1.2 to 3.Under the influence of the modifiers, the viscosity and turbidity of concentrated CA solutions are reduced; the specific bulk electrical resistance of films containing modifiers is reduced by several orders of magnitude.Translated from Khimicheskie Volokna, No. 3, pp. 45–46, May–June, 1984.     

Production of glass–ceramics from incinerator ash using lab-scale and pilot-scale thermal plasma systems

This research employed two thermal plasma melting systems and vitrification technology to treat incinerator ash. The melted slag was used for the production of glass–ceramics via powder sintering and heat treatment. When using the pilot-scale plasma molten system, the melt was rapidly quenched in water to yield glassy slag. The properties of quenched slag glass–ceramics were superior to that glass–ceramics produced by slowly cooling the slag with air. The glass–ceramics with the best physical/mechanical properties and chemical resistance was produced by heat treatment at 1150 °C for 2 h. Diopside and gehlenite were formed as the major crystalline phases. Glass–ceramics produced from incinerator ash demonstrate great potential for reutilization as non-porous or water permeable materials.     

Effect of vibromilling on the sintering and properties of magnesia

Conclusions The vibrogrinding of magnesia reduces the temperature at which complete sintering occurs from 1950 to 1850°C, and increases the density and strength of the specimens.The vibrogrinding of magnesium oxide makes it possible to obtain homogeneous thermoplastic slip for the hot pressing of refractories under pressure, and greatly reduces the concentration of temporary bond in the material.The material made from pure magnesium oxide, vibroground for 15 min, has a very high specific volume electrical resistance, electrical strength, vacuum sealing values with a vacuum of 10^–6 mm Hg, and a low tangent of dielectric loss.Translated from Ogneupory, No. 3, pp. 57–60, March, 1971.     

Thermal decomposition and combustion of phosphorus-metal-containing cellulose materials

Fire-retardant systems (FRS) consisting of a phosphorus-containing combustion retardant and metal (copper, chromium, cobalt, and nickel) salts which ensure elevated fireproofing indexes and resistance of cellulose cloth and cloth made of a mixture of cellulose and polyester fibre to wet treatments were proposed. It was shown that phosphorus-metal-containing FRS change the direction of reactions in thermolysis of cellulose material both in the condensed and in the gas phase of combustion, significantly decreasing the toxicity of the volatile products of thermolysis.Translated from Khimicheskie Volokna, No. 5, pp. 38–40, September–October, 1995.     

Adsorption of Oligomers from Dilute Solutions by Carbon, Basalt, and Glass Fibres

Use of the theory of volume filling of micropores for describing adsorption equilibrium in the phenol—acetone—fibre system made it possible to characterize adsorption by carbon, basalt, and glass fibres at different temperatures and to calculate the parameters of the pore structure of these fibres using the basic equation from the theory.     

Pressureless sintering and mechanical properties of SiO2–Al2O3–MgO–K2O–TiO2–F (CaO–Na2O) machinable glass–ceramics

To develop a high strength machinable glass–ceramic through pressureless sintering, the glassy compositions were obtained by mixing a mica-based frit and a frit in the SiO₂–CaO–Na₂O system. According to XRD results, the glass compositions mainly crystallized into phlogopite and diopside after sintering. The optimum sintered glass–ceramic with desirable mechanical properties, machinability and sinterability was achieved by addition of 30 wt.% SiO₂–CaO–Na₂O glass powder to 70 wt.% mica glass composition. SEM results confirmed presence of needle-like diopside crystals which played a reinforcement role to the platelet phlogopite and glassy matrix combination. The measurements showed bending strength and fracture toughness enhanced up to 144.6 ± 17.6 MPa and 1.7 ± 0.2 MPa m^1/2, respectively.     

Processing viscose yarn on basic knitting machines

Conclusions The material volume of fabrics from viscose textile yarn of linear density 6.7 tex is considerably less, and the basic qualities are the same as, cloth from serially produced viscose yarn of 8.4 tex linear density.The runnability of an experimental yarn of 6.7 tex linear density on basic knitting machines is considerably better than that of yarn of 8.4 tex linear density, which permits one to increase the productivity of labor and equipment.The use of viscose yarn of 6.7 tex linear density permits one to expand the assortment of tricotage articles with a significant reduction in volume of material and cost of production.This work was performed under the direction of Professor M. P. Nosov.Translated from Khimicheskie Volokna, No. 1, pp. 12–13, January–February, 1985.     

Electrochemical Behaviour of Al, Al—In and Al–Ga–In Alloys in Chloride Solutions Containing Zinc Ions

The electrochemical behaviour of Al, Al—In and Al–Ga–In alloys in 0.6 m NaCl solutions with and without Zn²⁺ was investigated. The study was performed by means of open circuit potential, potentiodynamic polarization, potentiostatic current-time and electrochemical impedance spectroscopy measurements as well as by SEM-EDAX examination. It was found that the Al—In alloy exhibits the highest negative open circuit potential in 0.6 m NaCl and the corrosion resistance of the tested electrodes decreases in the following order: Al > Al–Ga–In > Al—In. The greater activity of the Al—In alloy was interpreted on the basis of the autocatalytic attack by indium. The potentiostatic current–time measurements in Zn²⁺ containing electrolyte at potentials above the pitting potential revealed that Zn²⁺ has an insignificant influence on the Al electrode, while it enhances the corrosion of the Al–Ga–In alloy and improves the attack morphology of the Al—In alloy. Furthermore, the impedance spectra recorded under open circuit conditions showed a decrease in the polarization resistance of Al—In and Al–Ga–In alloys in presence of Zn²⁺ indicating the activating effect of Zn²⁺ ions.     

Laboratory instrument for accelerated determination of thermo-oxidative resistance of fibres

Conclusions A rapid method has been developed for determining the thermo-oxidative resistance of a fibre.An electrical laboratory instrument has been devised for determining the specific thermo-oxidative resistance of fibres in air over a wide temperature range (200–1500°C).Translated from Khimicheskie Volokna, No. 5, pp. 59–60, September–October, 1989.