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Powder Metallurgy аnd Functional Coatings (Izvestiya Vuzov. Poroshkovaya Metallurgiya i Funktsional'nye Pokrytiya)

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No 2 (2014)
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Production Processes and Properties of Powders

3-7 1023
Abstract

There were showed results of measurements of surface area for powders of aluminium-cerium alloys (3 at. %), aluminium-yttrium alloys (3 at. %), and aluminium-samarium alloys (1,5 at. %), as well as three-component aluminium-calcium-lanthanum alloy (at 1,5 at. % of each). In which case were used 3 methods: dynamic method of argon’s thermal desorption; calculation on BET (from argon’s adsorption isotherm); on Harkins-Jura equation. There was draw conclusion about advantages of BET on the ground of analysis. 

8-11 1027
Abstract

There was undertaken experimental studies of mechanical activation (MA) of stoichiometric mixture of titanium and nickel powders (Ti–55,06 wt.%Ni) and subsequent SHS combustion (self-propagation high-temperature synthesis) in the mode of thermal explosion. Process MA carried out in high- energy planetary ball mill (60 g) in air during from 30 s to 10 min. Thereafter received mixture was placed in specially designed unit of constant vo- lume where was carrying out heating up to thermal explosion occurrence. There was determined temperature of the heat evolution’s beginning, critical and maximum temperature by using pattern of temperatures. Structure and composition of studied mechano-activated powders and com- bustion products were investigated by means of scanning electron microscopy, optical metallography, and X-ray phase analysis. It has been found that nonmonotonic time dependences of thermal explosion’s temperature characteristics were connected with self-lining processes that lead to de- viation of activated mixture’s composition from original composition. 

11-16 885
Abstract

There were determined relationships of joint electron reduction process of lanthanum and boron ions in chloride-fluoride melts and established optimal conditions of electrochemical synthesis of borides’ fine dispersed powders LaB6 and LaB4.

Refractory, Ceramic, and Composite Materials

16-23 1056
Abstract

There was investigated interaction during sintering of finely dispersed compositions «high speed steel of grade OB1 of manufacturing «Höganäs» (Sweden) – titanium carbide». Content of TiC ranges in the interval of 20–80 vol.%. During liquid phase sintering was determined substantial melt’s dilution (face-hardened phase of cermet) by alloying elements as far as increasing of volume fraction of refractory phase, which dissolved alloying component of steel. This process limits concentration of core material (MeIV,VC) and reduced efficiency of the additional heat treatment, ensuring improvement of mechanical characteristics of steel and cermet in the whole. 

23-31 914
Abstract

There were investigated peculiarities of nano sized additions’ influence WC, ZrO2, as well as micrometric particles of hexagonal BN on compatibility un- der cold pressing of briquettes, shrinkage under solid-phase sintering, as well as on mechanical properties (bending strength, hardness) of powder alloys in the system Cu-Fe-Co-Ni. There was showed that introduction of alloy additives WC, ZrO2 and hexagonal BN has negligible influence on resistance of charging material to packing under cold pressing, and under sintering these additives are additional diffusion barrier, increasing energy of activation. At the expense of realization of dispersion hardening effect in compact composite was reach increase of hardness up 7 HRB and strength up 200 MPa. 

31-36 1090
Abstract

There were summarized relationships of reaction execution’s carbides of transition metals of IV, V groups with nickel. There was specified that interac- tion of near to stoichiometry carbides MeIV,VC with Ni characterized by predominant carbon impregnation, and carbides with strong defective proper- ties – metal impregnation. Accordingly, there is changed composition of carbide phase. Velocity of carbide composition’s alteration in the process of impregnation increases in the range MeIVC → MeVC, as well as with the growth of relation Me/X in the field of it homogeneity. There was demonstra- ted that chemical activity of carbides MeIV,VC in the mixtures with nickel are function of thermochemical activity of components, contained in it com- position. There was affirmed experimentally that systems MeIV,VCx (x → 1) – Ni are not quasi-binary. There was demonstrated that dissolving of nickel in the lattice of carbides MeVC leads to suppression of phase translation disorder – order and stabilization of structure of type NaCl. 

Modification of Surface Including Charged Particle Beams and Photon and Plasma Fluxes

36-42 913
Abstract

There were described results of investigations of microstructure and micro hardness of surface layer of collar step on disk plate from powder pseudo alloy steel – copper after carrying out of laser thermal treatment by fiber laser with capacity of 1 kW. There was revealed that under laser thermal treatment of pseudo alloy steel – copper except of full melting zone is developed field of partial flashing, that occurred in the volumes of low-melting component (cop- per) in parent structure and contacting sites of steel matrix. Then followed zone of quenching from solid state, in which for better samples was reached maximum micro hardness up 1000 HV in the volume of martensite, forming in perlite colony of initial material steel – copper. 

Nanostructured Materials and Functional Coatings

43-50 909
Abstract

There were carrying out investigations of processes of structuring and phase formation during receiving of composite ionic-plasma vacuum- arc nano crystal coatings TiN–Ni in broad interval of concentrations of nickel (from 0 to 26 at.%). There was defined that introduction of Ni into composition of coating leads to milling of crystallites of nitride phase. Average grain size of TiN reduced from 100–120 to 15–18 nm under alteration of concentration Ni from 0 to 12 at.% and normal distribution pf grain size. Further increasing of Ni composition accompanied with transition to polymodal distribution of particles with increasing of average diameter up 27 nm for tertiary mode. At concentration of Ni up 12–13 at.% nickel in coating is in X-ray amorphous state. Under it increasing more than 13 at.% in the composition of coating is formed intermetallide TiNi. This, in turn, stipulated appearance of porosity in the structure of deposited layer. Simultaneously with formation of intermetallide decreasing blocking role of nickel, and this is appeared in the growth of single grains of TiN up 30–35 nm. Coatings TiN–Ni are characterized by thermal stability of structure and composition at heating up 800 °C. 

50-54 911
Abstract

There were presented results of investigations of tribological properties of trial steel prototype with pyrolytic chromium carbide (CrC) with the use of up- grade friction machine SMT-1. There was demonstrated that application of such coatings on the steel 40X allows improve frictional properties of steel disc’s of hydromechanics transmission (HMT), that will be lead to increasing of its abrasion resistance, cutting time of mutual skid, decreasing of tem- perature in the contact of working surface of friction disc and decreasing of warp of disc’s risk, which leads to degradation of HMT operating capacity. 

54-58 1105
Abstract

There was investigated compositional electrolytic coating with nickel matrix and nanodiamond of detonation synthesis with the use of X-ray structu- ral analysis and atomic force microscopy. There was demonstrated that introduction of diamond nanoparticles and electrolyte of nickel plating leads to decreasing of grains size and dimensions of coherent scattering regions, the growth of microstrain and increasing of parameter of crystal lattice of nickel coatings. There was determined that preliminary upgrading of nanodiamond surface by nickel compounds promotes to alteration of data of nickel coatings’ characteristics. 

58-62 913
Abstract

There was described method of electroexplosive evaporation of electro erosion resistance composite coatings of systems W–Cu, Mo–Cu, Ti–B–Cu, W–C–Cu, Mo–C–Cu. With the use of optical interferometry, scanning electron microscopy and X-ray microanalysis were studied relief of its surface and phase composition. There was defined that coatings have cohesive-adhesive bond with material of contact surface. There were determined pa- rameters of undulation. Coating thickness could be regulating in wide range (up 2 mm) depending on service conditions of concrete nomenclature of hardenable articles. Abrasion hardness of coatings is increasing by 2 times, and electro erosion resistance in the conditions of spark erosion up to 10 times in comparison with electrical copper M00. 

Application of Powder Materials and Functional Coatings

63-68 890
Abstract

There was considered impact of 3 % solution of NaCl and crude oil at temperature 80 °C during 1000 h on adhesion strength to normal shock of specimens of inner anti-corrosive coatings, used for protection of corrosion of petroleum pipelines. There was defined that used at present cri- teria of quality analysis on the base of RD 05.00-45.21.30-KTN-005-1-05 does not full and could not reliable assess quality of inner coatings. There were determined the main regularities of decreasing of adhesive strength and impact resistance: for aging in 3 % of NaCl the main mechanism – chemisorption and destruction of polymeric base, and in crude oil – ageing of polymeric base of lacquer coating. 



ISSN 1997-308X (Print)
ISSN 2412-8767 (Online)