INNOVATIVE TECHNOLOGY PLATFORM OF METALLURGICAL PRODUCTION OF AMORPHOUS AND CRYSTALLINE ULTRAFINE AND NANOSIZED COMPONENTS

UDC 621.318.3

I.A. Bezrukov

General Director

Close Joint Stock Company

 “Research-and-production enterprise “EPOS”

Novosibirsk, Russian Federation

V.N. Filimonenko

Deputy General Director

Close Joint Stock Company

“Research-and-production enterprise “EPOS”

Novosibirsk, Russian Federation

 

INNOVATIVE TECHNOLOGY PLATFORM OF METALLURGICAL PRODUCTION OF amorphous and crystalline ultrafine and nanosized components

 

To create new and innovative equipment, devices and aggregates for different branches of engineering industry the problem of industrial large-scale production of amorphous and crystalline ultrafine and nanosized components with targeted properties (such as physical–and-mechanical, physical-and-chemical, thermal, geometric and others) being the primary when forming the structured, modified and functional nanostructured materials providing extreme resource-constitutive operating abilities is imperative to be solved.

At present, the production of amorphous and crystalline ultrafine and nanosized powders as well as products, with the required characteristics and properties, manufactured of their basis is achieved by multiple processing steps using the most expensive equipment, which has unreasonably high costs of all types of resources. Herewith, the requirements to the products are not provided. Significant problem for the various branches of engineering industry are environmental requirements.

It is evident that the creation of an innovative technological platform for closed metallurgical production of amorphous and crystalline ultrafine and nanosized powders and the formation of surface layers and compact materials with extreme resource-constitutive operating abilities on their basis, in general or mainly, would assist to solve this problem.

Domestic industrial technologies and equipment being used to produce ultrafine and nanosized powders and products manufactured of their basis do not meet the modern requirements or already got out of date. This disable to start the serialization of innovative products of missile, space and aeronautical and power engineering based on conventional functional structural materials of powder metallurgy. In amorphous and crystalline ultrafine and nanosized powders producing sequence there are a lot of physical–and-mechanical, chemical and electrochemical limits and operations, which often leads to the formation of complex and hazardous waste and increase manifold the cost of final product.

As a rule, due to high cost and restrictions to provide the required properties of the product, which is obtained by means of conventional technology or being the result of low productivity and small production yield, this product is not allowed to be high-efficiently used. Some properties of ultrafine and nanosized powders and products manufactured on their basis can not be realized at all. The demand for these high-regulated powders can not be ensured by external supplies because its exports to Russia are either under restrictions, or delivered as a finished product. It is evident, that in the domestic industry the required components are produced by trace amounts by means of extremely complex and expensive multistage technology or are not produced at all.

Innovative technology platform of metallurgical production of amorphous crystalline ultrafine and nanosized components of different phase and structural composition and forming of the surface layers and compact materials on their basis consists of few subsystems: metallurgical subsystem, subsystem of powders preparation and activation, supporting subsystem of the physicochemical properties of aggregated heterosuspensions, providing subsystem of the physical contact between the components of coatings and substrates, supporting subsystem of interfacial coupling strength in the composite coating, subsystem of physicochemical coatings treatment.

Metallurgical subsystem consists of two units: Submered Arc Furnace Assembly [1] and complex melt (flux) processing facility. Innovation aspect of Submered Arc Furnace Assembly is its proprietary design features [2]:

- plasma torches with controlled distribution of characteristics of thermal, gas-dynamic and electromagnetic fields in the plasma flow, which operate under a batch layer, in a contact with it and with working arc coaxial electrodes-ore burning cascade without the bottom electrode, which do not pollute the ore by impurities and which do not have resource restrictions are used;

- reduction process is carried out by using the briquette of counted mineralogical and elemental composition involving hydrogen as a product of water decomposition which is integrated and optimized by composition, structure and size and re-circulating hot dusty gases moving along a specially organized furnace contour into plasmatrons located in specific mine sections. The source of hydrogen is autonomously functioning water steam generator with wide variation of the control parameters. The main reducing agent is hydrogen and carbon oxide. The processes are occulting without additional excess oxidant. Reducing agent is only required for reduction reactions and losses compensations. The kiln gas at furnace output should contain CO2 and H2O;

- reductive and energetic properties of plasma-forming gases and carbon reducing agent are properly used by control system. Due to recycle streams the reducing gas and chemical energy stored in it is used many times. Recirculation of hot dusty gas is provided by structurally organized contour: throat area - plasma torch located in characteristic areas of the mine furnace - furnace working zone;

- “high” shaft is designed for the workable reduction process as well as for proper integral normal and high-temperature reduction processes;

- gases and solids discharge into atmosphere, in accordance with the environmental requirements is provided. Herewith, the emission rate is sufficiently less than at traditional Submered Arc Furnaces;

- energy, reduction and kinetic properties of ore-smelting process components are proper realized and under maximum control in each specific area of “high” mine;

- introduction of correcting reducing agents including nano-sizes was made through the internal electrode into working area.

The strictly regulated process provides the production of ultrafine and nano-sized product of required composition and properties at high-gradient high-speed cooling.

In its turn, the out-of-furnace treatment assembly has the following innovative features:

- melt temperature rise is made by the coaxial plasmatron of new design that provides the controlled heating rate;

-the possibility to feed ultrafine modifier through the internal tubular electrode and powder modifier with nanosize alloy and modifiers by means of wire feeding machine is realized;

- magnetodynamic high-rate melt mixer providing maximum homogenization control is installed;

- the shape of new design, which provides the ability to control the melt mixing by inert gas dusted by ultrafine nanosized modifiers and alloy is installed;

- gate device that guarantees the metal quality and minimizes the melt losses is installed;

The out-of-furnace treatment assembly is used at the second stage after ore-smelting process to correct the product composition.

Subsystem of powders preparation and activation consists of the technologies as follows: electroerosion discharge, mechanical activation, thermal activation. Electroerosion discharge affects the geometrical shape of powders, their dispersion, stress state, micro and submicro-structures and aggregate stability. It has been found that the microhardness of tungsten carbide particles of cubic modification is 2800-3000 kgf/mm2, and the specific surface is 30-40 times higher than that of powders obtained by chemical technology methods.

During mechanical activation of powders in liquids the surface atoms link with those located deeper is weakened. Herewith, there are surface discharges and surface structures induced by adsorption, as well as the deformation of energy bands and other effects are taking place. This leads, in particular, to the fact that in our thermoelectro-phoretic coating method being recently developed the electro-phoretic mobility of carbide and metal particles after mechanical activation 1.3-2 times increases. In addition, the change of activated particles polarity is probable. In general, these effects increase the rate of electro-phoretic (EF) deposition, and its characteristics are improving: such as, density, thickness uniformity, etc. Thermal powder activation [ 3] enables effective technological decontamination, disposal of oxide films and other compounds from the powder surface, as well as to prepare the surfaces of core powder material and alloy additives to formation of eutectic compounds and, thereby, to reduce power inputs required for their formation. Activation is carried out under vacuum at temperatures from 200 ° to 1000 ° C.

Supporting subsystem of the physicochemical properties of aggregated heterosuspensions consists of various techniques of suspension preparation. These are mechanical mixing in the drums together with active bodies and ultrasonic mixing at high frequency oscillation application onto suspension. The subsystem allows directed forming of powder dispersion from micrometer units to tenths of micrometers and the generation rate of powder coating.

Providing subsystem of the physical contact between the components of coatings and substrates consists of electrophoretic deposition of previously activated powder mixtures technologies. These technologies are accompanied by electrophoresis phenomena, electro-osmosis and forced convection of dispersed particles, and provide the coating uniformity by geometrical parameters and by phase composition, as well as its sufficient technological strength. As example, the following technological characteristics of the EPhO process: EPh coverage rate of composition onto the surface of a part is 30-50 µm /s; covering power is ± 0,002 mm; adjustable coating thickness is 0,005-0,3 mm; specific power intensity is 6-10 W/cm2; automation percentage is 95-97%.

Supporting subsystem of interphase connection strength in the composite coating is based upon the powder composition sintering over a liquid by means of melting of one or more components of powder composition. The transition of disperse state into monolith is defined by spreading effect, wetting and diffusion through the inter-phase boundaries. Sintering of complex heterogeneous structures is especially effective when using concentrated energy flows. Herewith, the directional change of the phase composition and coatings structure is achieved. During production of wear-resistant coatings on the basis of resistance metals (Mo, W, Ti), and iron-group metals (Ni, Co,) carbides the layer microhardness is provided within 1200 to 1550 kgf/mm2, at a thickness of 20 ... 300 microns and porosity no less than 1%.

Subsystem of physicochemical coatings treatment consists of electrochemical grinding ensuring the high performance treatment of hard and heat-resisting materials with significant reduction of energy consumption for the removal of material and pulse plastic deformation of the coating in ultrasonic field enabling to significantly improve the surface layer quality parameters (microhardness, surface roughness, of phase rotation uniformity in the coating).

Volume compacting of nanopowders is essentially connected with their features, i.e. high specific surface, a tendency to agglomerate, significant interparticle and wall friction forces during compacting, high elastic compacts aftereffects that requires to mark up the specific requirements to the elements (units) and to functions of the high-temperature presses meant for hot-pressing under vacuum. Traditional pressing in closed molds is enough simple and universal to be technologically realized for pressing of various shapes products made from the powders of different compositions and sizes. It has many traditional disadvantages, such as: uneven distribution of volume shaped product properties and inability of close approach of the density value to its physical size (characteristics). It is essential that the friction of the material pressed against the mold walls and intraparticulate friction inside the material leads to corresponding micro-and macro-defects. Reducing the friction forces of various kinds is possible by applying lubricants and plasticizers being a source of contamination of the material by residual porosity and other defects

Therefore, for volume compacting we use the ultrasound pressing with wide resonance curve and provide specially organized supply of generated ultrasonic vibrations to guide the ultrasonic vibrations directed by certain controlled technique about to the pressing axis.

Fundamental factor in accelerating of economic growth in industrialized countries was the rising of "lean" information technology (LeanIT) providing the crush of costs and time at development, manufacturing, operation and disposal without environmental impacts of high-tech products. (Основополагающим фактором ускорения экономического роста промышленно развитых стран стало возрастание «бережливых» информационных технологий (LeanIT) и обеспечивающие сокрушение финансовых и временных затрат при разработке, производстве, эксплуатации и утилизации без экологических последствий наукоёмкой продукции – Не очень понятна структура русского проедложения. – Прим. переводчика).

According to experts opinion, the using of CALM- technology provides cost reduction for design ( up to 30%) , time reduction for development (up to 2 times), time reduction for bringing out of products to the market (up 75%) , as well as cost reduction for preparation of technological and in-line documentation. Obviously, the use of CALM-technologies meant for recently created and partially realized presented platform, following the main stages of priorities development of technological platform in metallurgical manufacturing of high-tech market products, would increase its efficiency and competitiveness.

The use of CALM- technology also makes it possible to optimize the duration of the development of new commercial products in metallurgical industry, to provide the innovation of design and technological environment for their release and the establishment of regulated criteria for their suitability to the viability and safety. When implementing the project the international relations with the International Council on Systems Engineering, Massachusetts Institute of Technology , as well as the adaptation of international standards ISO15288, ISO 15296 and ISO 61508 are carried out.

Thus, the creation of an innovative technological platform in metallurgical production of amorphous and crystalline ultrafine and nanosized powders of different phase and structural composition and the formation of surface layers and compact materials on their basis is provided by current CALM information technology support and enables significantly reduce the costs of various resources.

References:

1.V.V. Pavlov, A.G. Pomeshhikov, I.A. Bezrukov, S.N. Malyshev. Plasma shaft ore-smelting furnace of a new generation. М. - Electrometallurgy // 2010, № 1. – p. 13-17 (in Russian)

2.   I.A. Bezrukov. Method of melting process and the device for its implementation. Patent № 2361375 (in Russian)

3.       I.A. Bezrukov, S.N. Malyshev. Method for resistance metal purified fine powder production and the device for its implementation. Patent № 2389584.

I.A. Bezrukov,  V. N. Filimonenko ©