Eugene Medvedovski

Lightweight ceramic composite armour system

Abstract The development of lightweight armour systems for ballistic protection is under continuing attention of the manufacturers and users. A new design of the composite armour systems has been developed and ballistically tested. A new armour system consists of a ceramic plate, an intermediate ceramic–polymer layer and a polymer fibre lining as a backing material. The proposed composite armour systems prepared with a use of specially selected compositions of the intermediate layer promoting the absorption of the kinetic energy of projectiles provide adequate ballistic protection to National Institute of Justice (NIJ) level III and level IV, and they successfully withstand multiple hits.

Advanced indium tin oxide ceramic sputtering targets (rotary and planar) for transparent conductive nanosized films

Abstract Abstract Indium tin oxide (ITO) ceramic sputtering targets used for the manufacturing of transparent conductive thin films for electrodes in flat panel displays, solar cells, touch panels, antistatic films and others developed and commercially produced are described. Thanks to optimised compositions and developed technology, commercially producing large size planar and new generation rotary ceramic target components have high density (up to 99·5% of theoretical density), uniform microcrystalline structure and superior properties, e.g. low electrical resistivity. As a result, nanosized thin films produced by direct current magnetron sputtering from the developed targets have uniform nanocrystalline or amorphous structures and superior transmittance (>90%) and low electrical resistivity. The morphology and properties of these films have been studied, depending on the film processing features. The benefits of the developed ITO rotary targets for industrial nanosized film processing (e.g. significant increase in process efficiency, about three times higher target utilisation, practically no nodule formation and particle redeposition during sputtering and reduced processing cost) are outlined.

Tribological properties of boride based thermal diffusion coatings

Abstract Engineering components, e.g. tubing systems for the down-hole applications in the oil and gas industry (in particular, sucker rod pumps, progressing cavity pumps and some other components of the artificial lifting systems), as well as numerous valves and seats, bearings, gears and plungers, require protection against friction and sliding abrasion service conditions. The hard boride based coatings on steels and alloys obtained through the thermal diffusion process have a high potential for these severe application conditions over many other types of coatings as they can be obtained on the entire working surfaces of large size and complex shape products. Intensive tribological studies of the iron boride based coatings on carbon steel obtained at Endurance Technologies Inc. have been conducted using the Cameron–Plint testing unit (reciprocating sliding of the metallic rod under the load over a flat surface of the coated samples). The friction wear loss, friction coefficient and structural changes of the coatings have been studied in dry and lubricating (water–oil) friction conditions, which simulate actual application conditions. It was demonstrated that the obtained boride coatings have the friction loss significantly smaller than untreated steel (e.g. ∼10–30 times in the dry conditions and at least 5 times in the lubricating conditions) with no peeling and flaking-off. The friction coefficients of the boride coatings are steady over the test duration. The influence of the thickness on the boride coatings performance is demonstrated. The encouraging results are explained by the specific coating structure of the hard coating obtained through the thermal diffusion process and the thin ‘tribofilm’ formed during a friction mode.

Large sized SiC based wear, corrosion and thermal shock resistant ceramics produced by thixotropic casting technology

Abstract Manufacturing large sized structural ceramics is quite challenging, especially for wear, corrosion and thermal shock resistance applications, when monolithic complex shapes, such as cyclones, pipes, cones, elbows and other components with sufficient wall thickness (up to 50–75 mm), are required. Shaping from thixotropic slurries containing particles of various sizes allows processing complex large sized (up to 1 m diameter and height) components for structural applications. This versatile technology that does not require expensive and complicated equipment was successfully applied for manufacturing silicon carbide based large size ceramic components. Heterogeneous SiC based ceramics with additives, such as Al2O3, Si3N4, mullite and some others, have been developed and commercially manufactured using thixotropic casting. The developed composition and processing are based on the oxide bonding mechanism. The structure and some physical properties of SiC based ceramics, e.g. wear resistance, are described. The manufactured components are successfully used for the mentioned applications in mineral, mining, oil and gas processes, power generation, metallurgy and some other areas. This paper summarises the principles of formation of oxide bonded SiC based ceramic large size components using thixotropic casting, which is the result of the development and processing of obtained ceramics in industrial conditions conducted during a number of years and their industrial applications.

Boride-based coatings for protection of cast iron against wear

The components made of cast irons require protection against wear in severe service conditions. Surface engineering can be used to prevent mechanical failures of cast iron components due to excessive friction-related wear. The iron boride-based coatings can be applied on the entire working surfaces of large-size complex shape cast iron components through the thermal diffusion process. Tribological properties of these coatings obtained have been studied using the pin-on-disc test configuration in simulating application conditions. The obtained iron boride coatings demonstrated significantly lower wear losses compared to bare cast iron, stable behaviour of coefficient of friction during time and no structural degradation and spalling. The superior wear resistance of boride-based coatings on cast iron is dealt with the combination of their high hardness, specific ‘sawtooth’ double-layer morphology obtained through the thermal diffusion process, diffusion-related bonding to the substrate, self-lubricating thin ‘tribo-film’ formed during friction and high thermal and chemical stability.