The technology for obtaining of porous powder materials with frame structure on the basis of spherical particles of titanium powder, using application of technological coatings of Тi (Si+Мо), (Si+С) or (W+С) was developed. Formation of the powder with the coating was conducted in molding die under the pressure below the flow limit (under 200 MPa). Reaction sintering in a vacuum furnace was carried out at the temperature of 900 оС with the exposure within 1 hour, which allowed receiving penetration factor over 39·10-13 m2 with the formation of powder porous materials with isotropic structure and increased properties.
It is suggested to use steel shot with the structure of tempered martensite for smelt modifying in the capacity of carrier-modifier. It was applied barrier nickel layer and then wolfram nano-coating (over 200 nm) along with protective cobalt layer, which prevents interreaction of oxygen with wolfram surface. Introduction of the modifier creates subcooling zone. When it interreacts with smelt the process of active mixing of the modifier with the smelt takes place. Subsequent crystallization carries involving large number of crystallization centers, which leads to reduction in the structure graininess and velocity and plasticity increase by 2-3 times.
The technology of production of porous powder materials with frame structure on the basis of spherical particles of titan powder by means of applying on them technological coverings (Si + Mo) + C with the thickness up to 2 mm is developed. Formation of powders with covering was carried out in the mold at pressure below yield point (up to 150 MPa).
The problems of applying nanolayers of tungsten, molybdenum, cobalt, silicon carbide, carbon, applied by magnetron distribution system on the powders of iron groups, followed by their introduction to the steel melt. The structure and properties of a coating modifier and its impact on the structure and properties of the steel are studied.
The problem of porous powder materials obtaining from spherical stainless steel powders has been solved by the nanotechnology development. The technology make it possible to form condensate on the powder particles surface with the thickness of more than 300 nm from Si and (Si + C) or (Mo – Si)-element mixture layers. The shearing deformation of the elements during formation permits to activate surface layers and subsequent isothermal heating leads to the ceramic coating generation and spherical 12Kh18N10T-steel powder sintering.
The technology of coatings deposition with thickness up to 5 micrometers on the activated surface of steel shot is developed. The composition and arrangements of layers in covering of the steel shot intended for modification of steel are chosen.
A technology has been developed to obtain porous powder materials on the basis of spherecal powder particles of 12Х18Н10T сorrosion-resistant steel by technological coating deposition on them –condensate from layered and composite Si and (Si + C) or Si and (Mo + Si) nano-layers. Their deformation at points of spherical particles contact creates press forming conditions with sufficient strength rate at pressure below yield point of steel powder (below 200 MPa). The subsequent sintering occurring with an exothermic reaction in the coating ensures particle sintering in their local heating within 1100–1200 °С temperature range.
Production of porous powder materials from spherical powders of corrosion-resistant steel 12Х18н10Т with formation at low pressures 120-140 mpa in the mold with the subsequent activated sintering became possible due to increase of duration of process of spattering and formation of condensate particles (Si-C) or (Mo-Si) on surface.
Structure formation in laminated coatings (Si + C) and a cobalt alloy ЭП 131 on magnetronically sprayed diamond crystals with subsequent heating in a dilatometer up to 1400 °C is accompanied by formation of amorphous and crystal SiC-layer within temperature interval of 650–850 °С and a layer of cobalt ЭП-alloy. Adding of KCR06-hard alloy granules in furnace charge leads to sintering of tungsten carbide inside of the granules and with diamond crystals through SiC coating and alloyed cobalt binder at temperature of 1400 °C.
Coating structure formation under magnetron spraying of titanium and carbon cathodes and combined cathodes, namely cobalt (EP 131) – nickel, tungsten – carbon have been investigated under conditions of carbide separate synthesis within the temperature range of 650–1200 °C. Usage of cobalt and nickel particles as matrix material leads to their rapid thermal expansion under heating during sintering process in the dilatometer. Subsequent plastic deformation of sintered samples provides obtaining a composite powder material that is a composite with framing structure of cobalt, titanium and tungsten carbides in the coatings.
Investigations of morphology of surface deterioration of sintered powders with covering are reflected. It is shown that formation of structure and characteristics of composite material is determined considerably by state of the surface and structure of particles covering.
The paper presents results of graphite surface morphology research and graphite structure improvement (density increase) in nano-coatings of iron alloy powders while making isothermal heating up to 1200 °С and plastic deformation caused by tensile stress due to significant difference in iron and graphite thermal expansion coefficients. Framework structure formation of squeezed graphite on iron-group metal particles makes it possible to obtain composite powders for preparation of erosion-resistant composite materials.
The paper contains investigations on regularities of diamond - silicon carbide composite structure formation at impact-wave excitation. It has been determined that while squeezing a porous blank containing Si (SiC) nano-diamond by explosive detonation products some processes are taking place such as diamond nano-particles consolidation, reverse diamond transition into graphite, fragments formation from silicon carbide. A method for obtaining high-porous composites with the presence of ultra-disperse diamond particles has been developed. Material with three-dimensional high-porous silicon-carbide structure has been received due to nano-diamond graphitation at impact wave transmission and plastic deformation. The paper reveals nano-diamonds inverse transformation into graphite and its subsequent interaction with the silicon accompanied by formation of silicon-carbide fragments with dimensions of up to 100 nm.
The paper presents investigation results concerning evaluation of influence of technological parameters of composite cathode spraying in a planar magnetron spraying system on structure formation and properties of layer nano-coatings (Si + C) of diamond micro-powders . a-SiC formation reaction was proceeding in the nano-layer (up to 20nm) presenting Si + C atom or cluster mixture of amorphous structure being treated with glow-discharge plasma. The layer coating has been obtained as a result of subsequent deposition on it the following elements: Si + C and Al of the given thickness (up to 300nm and 10nm, respectively) and also outside layer of pyrolytic carbon. The coating has ensured diamond protection against graphitation while heating and formation of carbide-silicon matrix. The composite of silicon diamond-carbide obtained on the basis of diamond powders with a layer coating with the help of a method that presupposes impregnation with liquid silicon and reaction sintering is characterized by improved properties.
The paper presents investigation results concerning evaluation of influence of technological parameters of composite cathode spraying in a planar magnetron spraying system on structure formation and properties of layer nano-coatings (Si + C) of diamond micro-powders . a-SiC formation reaction was proceeding in the nano-layer (up to 20nm) presenting Si + C atom or cluster mixture of amorphous structure being treated with glow-discharge plasma. The layer coating has been obtained as a result of subsequent deposition on it the following elements: Si + C and Al of the given thickness (up to 300nm and 10nm, respectively) and also outside layer of pyrolytic carbon. The coating has ensured diamond protection against graphitation while heating and formation of carbide-silicon matrix. The composite of silicon diamond-carbide obtained on the basis of diamond powders with a layer coating with the help of a method that presupposes impregnation with liquid silicon and reaction sintering is characterized by improved properties.
