Magazine «Powder Metallurgy and Multifunctional Coatings. News ofHigher School»
Contents V. 4, 2011
POWDER PRODUCING PROCESSES AND PROPERTIES
Polushin N.I., Sorokin E.N., Orekhov T.V., Stepareva N.N.
Investigation of structure and particle-size distribution of DAGgrade ultrafine diamond powder
For the purpose of subsequent production of diamond polycrystals,detonation synthesis diamond powder (DAG) has been investigated as comparedwith the powder produced by static synthesis from graphite (ASM-S 2/1). X-rayphase analysis and X-ray crystallography as well as electron and opticalmicroscopy were used. Some structural features and properties are found andlacking of microstrains is observed in the DAG powder under investigation. Itsparticles are shown to have polycrystalline structure and the size ofcoherent-scattering regions to be 64 nm, negligibly being different from ASM-Spowder (88 nm). As experimentally found, DAG powder has the high tendency topowder particle agglomeration to formations of 0,2–0,5 μm in size. However upon holding for 5 min in liquid medium,aggregates up to 30 μm in size are observed.
Key words: detonation synthesis diamondpowder, microstructure, polycrystalline composite materials, X-raycrystallographic and X-ray phase investigations.
POWDER PRODUCING PROCESSES AND PROPERTIES
Sevostyanova I.N., Sablina T.Yu., Melnikov A.G., Kulkov S.N.
The effect of annealing and machining in ball mill on properties ofplasmachemical ZrO2–Al2O3–Y2O3 powders
The effect of annealing and subsequent low-energy ball-milling onthe morphology, phase composition, specific surface area (Ssp) andspecific volume (V) of nanopores in 20 wt. % Al2O3–80 wt. % (ZrO2 + 4mole % Y2O3) plasma-chemical powders has been investigated. The transformationsoccurred in the powder during heating and ball-milling result in changes of Sspand V in nanopores of different radiuses. Annealing of powders attemperatures above 1100 °C essentially reduces Ssp and V ofnanopores. Increase in specific surface area during ball milling is connectedwith fracture of hollow spheres and foam-like particles, rise of 3–20-nm radiuspore volume, as well as with the phase transfer of tetragonal to monocliniczirconia phase transformation.
Key words: zirconia, specific surface,phase composition.
THEORY AND PROCESSES OF POWDER MATERIAL FORMATION AND SINTERING
Basov V.V., Panov V.S., Myakisheva L.V.
Investigation of the effect of aggregates being in UO2 moldingpowder on fuel pellet compaction and sintering processes
The effect of different strength aggregates in compacted uraniumdioxide powders on the fuel pellet compaction and sintering processes has beeninvestigated to improve qualitative and operational characteristics of fuelpellets (fuel components of fuel elements at nuclear power stations). It isestablished that the aggregates do not fracture in the process of compactedpowder preparation and pellet compaction forming regions of increased porosityinside pellets during sintering, thus resulting in decrease of pellet density.Some factors affecting the density of prepared pellets have been investigatedand the ways of density increase are recommended.
Key words: pellet, aggregates,properties, compaction, sintering, compacted powder, porosity, density, volumeportion, accessory.
THEORY AND PROCESSES OF POWDER MATERIAL FORMATION AND SINTERING
Pribytkov G.A., Korosteleva E.N., Gurskikh A.V., Korzhova V.V.
Structure formation in sintering Ti–Cu powder mixtures
Volume changes of Ti–Cu powder mixtures containing 0–12 аt. % Cu in sintering have been investigated. The extreme characterin the concentration dependence of compact shrinkage is established. Phasecomposition, microstructure of sintered materials, and elemental chemicalcomposition have been examined by metallography, X-ray crystallography,and X-ray micro-crystallography. The role of the processes responsiblefor the structure formation during sintering has been discussed as well as theeffect of powder dispersivity, uniformity of copper distribution in powdermixture, and isothermal holding duration during sintering are considered.
Key words: titanium, copper, sintering,volume changes, powder dispersivity, microstructure, phase composition.
THEORY AND PROCESSES OF POWDER MATERIAL FORMATION AND SINTERING
Boiko V.F., Vlasova N.M., Zaitsev A.V.
Estimate of W and AlNi surface energy according to the results oftheir fine crushing
A solid surface tension determination method on the basis ofgeneralization of Rittinger’s law and Gibbs thermodynamics equation, diffractionanalysis of granulometric characteristics of finely divided powders –prototypes (Fe, Co) and original (W, AlNi) is proposed. Surface tensioncoefficients of tungsten and AlNi have been estimated. The confidence intervalsof varying their values are found.
Key words: surface tension coefficient;granulometric characteristics.
THEORY AND PROCESSES OF POWDER MATERIAL FORMATION AND SINTERING
Rusin N.M., Borisov S.S.
Fine-structural characteristics of powder compacts subjected toequichannel angular compaction
PA-2 grade coarse aluminum powders have been subjected toequichannel angular compaction with intensity of γ= 2 at room temperature. As a result, dense material with wide area of contactsamong particles was produced. However the compact strength remained low, itsfracture proceeds along the maximum conjugation planes of powders. The causesof low strengths of compacts are shown to arise from the features of chemicalcomposition and the topography of contacting surfaces of powders to be intensivelyplastically deformed.
Key words: aluminum powders, intensiveplastic deformation, equichannel angular compaction, structure.
REFRACTORY, CERAMIC, AND COMPOSITE MATERIALS
Onishchenko D.V., Wang Qingsheng, Popovich A.A.
Mechanochemical formation of functional nanocomposite systems foranode electrodes of lithium-ionic (polymeric) accumulators
Functional nano-composite materials have been formed fromreproducible vegetal resources and nano-sized elements for anodes oflithium-ionic (polymeric) accumulators.
Key words: nano-composite materials,reproducible vegetal resources, mechanosynthesis, mechanoactivation, nano-sizedelements, anodes, lithium-ionic (polymeric) accumulators.
POROUS MATERIALS AND BIOMATERIALS
Borisov B.V., Serov M.M.
Formation of porous fibrous materials by hung melt drip extraction
A method of forming porous material on the basis of metal fibersproduced by hung melt drip extraction (HMDE) has been proposed. An installationhas been designed and manufactured for production of porous fibrous materialsby HMDE. Samples of porous materials from fibers of heat-resistant andcorrosion-resistant steels, nickel alloys, zirconium, etc. are produced. Thebond formation mechanisms between fibers have been investigated and a model offiber interaction in the material being formed is proposed. According to theproposed model, an estimation of the opportunity of bond formation betweenfibers in porous material based on copper and steel fibers at variousextraction rates is made.
Key words: porous fibrous materials,melt extraction by rotating heat absorber.
NANO-STRUCTURED MATERIALS AND FUNCTIONAL COATINGS
Kameneva A.L.
Evolution of notions on structural zones of films formed by vacuumprocesses
It is established that the conditions of film formation andultimately their structure can be represented as schematic models of structuralzones (MSZ). The analysis of the materials of Russian and foreign publicationsfor a period of 1969–2011 shows that it is necessary to study the structural evolutionof films during their deposition as a function of temperature and processconditions for stabilization of the structure and operational properties ofpolycrystalline films. Construction of the MSZ allows finding the correlationbetween homologous temperature, evolution of structure, and technologicalparameters of the deposition process.
Key words: model of structural zones,polycrystalline films, evolution of structure, temperature and processconditions, homologous temperature.
NANO-STRUCTURED MATERIALS AND FUNCTIONAL COATINGS
Polushin N.I., Kudinov A.V., Zhuravlev V.V., Stepareva N.N., MaslovA.L.
Dispersed hardening of diamond composite electrochemical coating bynanoparticles
The article describes the results of the investigations concerned withthe nickel matrix hardening by nano-dispersed particles in diamond compositeelectrochemical coating. Nano-powders of diamond produced by detonationsynthesis, which were introduced into diamond composite electrochemical coatingthrough electrolyte, were used as a hardening phase. As a result, microhardnessof nickel matrix is increased 3 times and drilling tool resistance does 4times. The process developed can be used in the production of diamondinstrument to cut stone, glass, ceramic materials as well as for manufacture oftruing tools.
Key words: composite materials, sulfateelectrolyte of nickel plating, diamond layer, nanodiamonds, diamond compositeelectrochemical coating, diamond-galvanic drilling tools, dispersion hardening.
APPLICATION OF POWDER MATERIALS AND FUNCTIONAL COATINGS
Milyaev I.M., Alymov M.I., Yusupov V.S., Zelensky V.A., AnkudinovA.B., Milyaev A.I.
The effect of silicon and molybdenum on magnetic hysteresisqualities of powder 22Kh15KA hard-magnetic alloys
22Kh15KA-alloy permanent magnets characterized by relative densityof 95–96 % and maximum energy product (BH)max = 38 kJ/m3 at remanentinduction Br = 1,38 T (13800 Gs) and coercive power HcB = 46 kA/m(580 Oe) are obtained from element powders by powder metallurgy. The optimummode of sintering 22Kh15KA alloy permanent magnet powder compacts is determinedas following: medium is vacuum, t = 1405?1415 °C for 2,5–3,0 h up to relative density of 95–96 %. An additive of 1 wt. % Si into 22Kh15KAalloy increases the convexity of the demagnetization curve and rises (BH)maxto 44,5 kJ/m3 (5,6 MGs-Oe).
Key words: permanent magnets, powdermaterials, maximum energy product, remanent induction, coercive force.
APPLICATION OF POWDER MATERIALS AND FUNCTIONAL COATINGS
Antonova N.M.
Rheological properties of polymeric suspensions with ASD-1 powderused for production of composite coatings
The effect of polymer polymerization degree, viscosimeter spindlerotation speed, and temperature on the rheological polymeric properties ofsuspensions composed of sodium-carboxymethylcellulose with dispersed aluminumpowder has been considered. The suspensions are shown to be relative topseudo-plastic systems. Hardening of composite system structure that contains afilling compound – aluminum powder takes place at the cost of hydrogen bondsaccessible for interaction on OH-groups of polymer water solution.
Key words: suspension, viscosity,filling compound, sodium-carboxymethylcellulose, aluminum powder.
APPLICATION OF POWDER MATERIALS AND FUNCTIONAL COATINGS
Kem A.Yu., Chan Man Tung, Kitaev V.V.
Moessbauer and magnetic investigations of hot-compacted powder Fe–Psoft-magnetic material
Formation of magnetic properties of hot-compacted powder materialsin the Fe–P system is caused by the history of their production. The Moessbauerspectroscopy established the presence of uncontrolled impurity in the interfacefields and the existence of distorted near-border field where iron atoms havelocal symmetry of the nearest surrounding being lower than cubic one. The useof hot compaction process allows producing powder materials with high level ofmagnetic properties.
Key words: powder materials,iron–phosphorus, hot compaction, porosity, induction, magnetic permeability,coercitive force, Moessbauer spectroscopy.
INFORMATION
Ryzhonkov D.I., Filonov M.R., Lyovina V.V.
Specifics of curriculums and plans in training specialists in thesphere of nanomaterials and nanotechnologies
General and specific requirements to training of students in thesphere of nanotechnology and nanomaterials are considered. Criteria ofdrawing-up of the curriculums and plans have been developed. The necessity ofnew scientifically well-founded approaches to drawing-up, modernization andoptimization of the curriculums and plans for preparation of specialists in thesphere of nanosystems is shown.
Key words: curriculums, programs,training of specialists, nanotechnology, nanomaterials, training criteria, bachelor,magisters, specialists, post-graduate students.
