VOL 85, No. 4 (2012)

The perspective high-temperature glass-ceramic and ceramic composite materials developed at VIAM, which are distinguished by their ability to retain properties at high temperatures in an oxidizing environment, good wear resistance, excellent corrosion properties, low density, and low thermal expansion, are considered. The materials are not inferior in properties to the best foreign analogues, and in some characteristics they surpass them, which makes the developed materials uncontested for use in heat-loaded units and parts of promising products.

The creation of a reliable system for protecting beryllium from oxidation and sublimation of its toxic oxides during high-temperature heating is considered. The results of studying the kinetics of beryllium oxidation without a coating, with a passive film and a composite coating at heating temperatures up to 900 ° C for 50 hours are presented. > - B ₂ O ₃ - R ₂ O.

The paper presents the results of a study of physicochemical and structural processes occurring during heat treatment of glasses of strontium aluminosilicate composition using synchronous thermal analysis, X-ray phase analysis, electron paramagnetic resonance and optical spectroscopy. The dependence of the processes of structure formation on the chemical composition of the glass is investigated.

The technology for producing fibrous semi-finished products based on aluminosilicate fibers is presented, which made it possible to obtain equal density mats from 20 to 40% by volume and provided the possibility of obtaining a heat-shielding material with an adjustable volume fraction of a reinforcing filler. Investigations of the thermal conductivity and phase stability of samples of a heat-shielding material of the Gelarm type based on oxide fibers and an aluminosilicate matrix modified with components that slow down the crystallization and sintering of reinforcing fibers are presented.

Methods have been developed for softening and removing ceramic rods from a metal casting due to polymorphic transitions in cristobalite and ?-Ca ₂ SiO ₄ during vibration in water with surfactants without the use of aggressive and environmentally harmful reagents. Cristobalite ceramics had a hot bending strength at 1050 ° C of about 20 MPa, and ?-Ca ₂ SiO ₄ at 1300 ° C - 18-24 MPa, which is sufficient for its use as a material for rods. The use of a mixture of urea-formaldehyde resin with silica sol for powders from tridymite, mullite and zircon as a binder made it possible to achieve softening of the rods during cooling due to cristobalite polymorphism. The softening of the rods and their removal during vibration in water with surfactants is realized at the polymorphic transition from ?-Ca ₂ SiO ₄ to ? ??-Ca ₂ SiO ₄ in masses of MgO, ?-Al ₂ O ₃, fused SiO ₂, stabilized with ZrO < sub> 2.

The constant increase in the operating temperatures of modern aircraft and gas turbine plants requires an increase in the characteristics of ceramic materials, including heat-shielding and heat-insulating materials. Materials based on aluminum oxide fibers are most promising for use at temperatures up to 1750 ° C. Various types of fibers developed by FSUE "VIAM", their features, and application in materials are considered. Also presented are various types of fibrous heat-shielding and heat-insulating materials and their technical and operational characteristics.

The properties of fiberglass plastics based on polyimide, epoxy, phenolic and inorganic binders and various structures of glass fillers have been investigated. Fiberglass plastics based on epoxy binders are used for the manufacture of highly loaded structures. Glass fiber laminates based on polyimide, organosilicon and inorganic binders have been developed for operation at elevated temperatures. Examples of the use of fiberglass plastics in aircraft and rocket technology are given.