Мechanochemically synthesized nickel-containing aluminosilicate modifiers for tribotechnical aluminum alloys

2021 ◽  
Vol 4 ◽  
pp. 50-57
Author(s):  
S. A. Kovaleva ◽  
◽  
T. F. Grigoreva ◽  
P. A. Vitiaz ◽  
V. I. Zhornik ◽  
...  
Keyword(s):  
Mechanical Activation ◽  
Structural Changes ◽  
Primary Silicon ◽  
High Energy ◽  
Micro Hardness ◽  
Composite Powders ◽  
Oh Groups ◽  
Silicon Crystals ◽  
Nickel Composites ◽  
Wear And Corrosion Resistance

Silumins are promising antifriction alloys for the manufacture of friction units. They have a low density, high wear and corrosion resistance. However, they own low hardness and strength, which leads to the need to develop modifying and strengthening additives. Aluminosilicates have a density close to silumin and can be used for its strengthening, but they are characterized by low wettability by metals. To improve wettability, it is necessary to modify the aluminosilicates with metals. The aim of this work is to study the mechanochemical synthesis of aluminosilicate/Nickel composites and modification of silumin using them. Structural changes in powder mixtures of natural aluminosilicates with Nickel during high-energy mechanical processing in a planetary ball mill, as well as in alloys of the composition silumin + potassium fluoroborate and silumin + potassium fluoroborate + aluminosilicate/Nickel obtained by hot pressing of mechanoactivated powders, were studied using Fourier-infrared spectroscopy and x-ray diffraction analysis. It is shown that mechanical activation of a mixture of silumin + potassium fluoroborate powders leads to a redistribution of silicon during sintering with the formation of large primary silicon crystals and a decrease in micro hardness by ~ 20 %. Mechanical activation of aluminosilicates with Nickel leads to the formation of composite powders with the removal of OH groups and the formation of SiO2 framework structures. The use of such a modifier during sintering of the silumin alloy leads to the formation of a homogeneous fine structure of the alloy with the grinding of eutectic and primary silicon grains, which increases the micro hardness of the alloy by 1.5 times.

Modification of the structure of the hypereutectic silumin alloy Al-44Si under the action of compression plasma flows

2021 ◽  
Vol 1 ◽  
pp. 40-50
Author(s):  
V.I. Shimanski ◽  
◽  
A. Evdokimovs ◽  
V.V. Uglov ◽  
N.N. Cherenda ◽  
...  
Keyword(s):  
Energy Density ◽  
Elemental Composition ◽  
Phase State ◽  
Primary Silicon ◽  
High Energy ◽  
Absorbed Energy ◽  
Plasma Flows ◽  
Compression Plasma Flows ◽  
Silicon Crystals ◽  
Melted Layer

Effects of the high-energy compression plasma flows on the structure, elemental composition, and phase state of Al-44 at.% Si hypereutectic silumin alloy have been investigated. Using scanning electron and optical microscopy it was found decreasing in grain size of both primary silicon particles and Al-Si eutectic parts with increase of absorbed energy density of compression plasma flows. The primary silicon crystals were dispersed down to 300 nm in the result of high cooling rate of the melted layer after its homogenization by means of hydrodynamic mixing. It was found that increase in the absorbed energy density, homogenization of elemental composition in the modifies layer occurs due to increase in lifetime of the melted state and more efficiency mixing process.

Synthesis of TiN/Si3N4 composite powders by mechanically activated annealing

2005 ◽  
Vol 20 (4) ◽  
pp. 864-873 ◽  
Author(s):  
J.M. Córdoba ◽  
R. Murillo ◽  
M.D. Alcalá ◽  
M.J. Sayagués ◽  
F.J. Gotor
Keyword(s):  
Mechanical Activation ◽  
Room Temperature ◽  
Milling Time ◽  
Isothermal Annealing ◽  
High Energy ◽  
Nitrogen Atmosphere ◽  
Composite Powders ◽  
High Energy Milling ◽  
Synthetic Reaction

TiN/Si3N4 composite powders were obtained by a process that combines the mechanical activation of titanium and silicon powders at room temperature through high-energy milling with an isothermal annealing in a nitrogen atmosphere to complete the synthetic reaction. Mechanical activation has allowed us to complete the synthesis at 1350 °C only. The β–Si3N4 content in the final powder tends to increase as the milling time is prolonged. The microstructure of the TiN/Si3N4 composite powders has a bimodal character composed of TiN and β–Si3N4 grains and α-Si3N4 nanowires. Diameters of the nanowires range from 10 to 70 nm.

Structural changes of silicon crystals after high-energy electron irradiation

2004 ◽  
Author(s):  
A. G. Gimchinsky ◽  
B. I. Gutsulyak ◽  
A. V. Oleynich-Lysyuk ◽  
N. D. Raransky ◽  
Z. Swiantek
Keyword(s):  
Electron Irradiation ◽  
Structural Changes ◽  
High Energy ◽  
Energy Electron ◽  
High Energy Electron ◽  
Silicon Crystals

Impact of the SiC addition on the morphological, structural and mechanical properties of Cu-SiC composite powders prepared by high energy milling

2021 ◽  
Author(s):  
Nailton T. Câmara ◽  
Rafael A. Raimundo ◽  
Cleber S. Lourenço ◽  
Luís M.F. Morais ◽  
David D.S. Silva ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Energy ◽  
Composite Powders ◽  
High Energy Milling

Physical and Electrochemical Properties of SiOx /C Composites Prepared by a Combination of Spray Pyrolysis and High Energy Ball Milling

2015 ◽  
Vol 1775 ◽  
pp. 7-12 ◽  
Author(s):  
Anara Molkenova ◽  
Izumi Taniguchi
Keyword(s):  
Electrochemical Properties ◽  
Spray Pyrolysis ◽  
Ball Milling ◽  
Ultrasonic Spray Pyrolysis ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Potential Range ◽  
Composite Powders ◽  
Ultrasonic Spray ◽  
Energy Ball

ABSTRACTSpray pyrolysis has been widely used to prepare homogeneous and uniform ceramic powders with high purity. In this study, we are proposing ultrasonic spray pyrolysis followed by heat treatment to produce SiOx/C composite powders, where sucrose was used as a carbon source. Furthermore, high energy ball milling of the as-prepared powders in the presence of acetylene black was conducted to activate its electrochemical properties by reducing the particle size and improving the functionalization of the SiOx composite particles. SiOx/C nanocomposite finally obtained at a sucrous concentration of 0.1 mol L-1 showed superior electrochemical properties, and the SiOx/C nanocomposite electrode delivered the first discharge and charge capacities of 1252 and 819 mAh g-1, respectively, with an initial columbic efficiency of 65% at a current density of 50 mAh g-1 in the potential range from 0.01 to 3 V versus Li/Li+.

Development of Ni/h-BN Self-Lubricating Composite Powder by High-Energy Ball Milling

2016 ◽  
Vol 869 ◽  
pp. 277-282
Author(s):  
Moisés Luiz Parucker ◽  
César Edil da Costa ◽  
Viviane Lilian Soethe
Keyword(s):  
Ball Milling ◽  
Milling Time ◽  
Solid Lubricants ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Second Phase ◽  
Average Particle ◽  
Composite Powders ◽  
The Matrix ◽  
Energy Ball

Solid lubricants have had good acceptance when used in problem areas where the conventional lubricants cannot be applied: under extreme temperatures, high charges and in chemically reactive environments. In case of materials manufactured by powder metallurgy, particles of solid lubricants powders can be easily incorporated to the matrix volume at the mixing stage. In operation, this kind of material provides a thin layer of lubricant that prevents direct contact between the surfaces. The present study aimed at incorporating particles of second phase lubricant (h-BN) into a matrix of nickel by high-energy ball milling in order to obtain a self-lubricating composite with homogeneous phase distribution of lubricant in the matrix. Mixtures with 10 vol.% of h-BN varying the milling time of 5, 10, 15 and 20 hours and their relationship ball/powder of 20:1 were performed. The effect of milling time on the morphology and microstructure of the powders was studied by X-ray diffraction, SEM and EDS. The composite powders showed reduction in average particle size with increasing milling time and the milling higher than 5 hours resulted in equiaxial particles and the formation of nickel boride.

Detection of fungal decay by high-energy multiple impact (HEMI) testing

Holzforschung ◽  
2006 ◽  
Vol 60 (2) ◽  
pp. 217-222 ◽  
Author(s):  
Christian Brischke ◽  
Christian Robert Welzbacher ◽  
Andreas Otto Rapp
Keyword(s):  
Structural Changes ◽  
Brown Rot ◽  
High Energy ◽  
White Rot ◽  
Fungal Decay ◽  
Highly Correlated ◽  
Thermally Modified Wood ◽  
Impact Milling ◽  
Multiple Impact ◽  
Steel Balls

Abstract The suitability of a previously described high-energy multiple impact (HEMI) test for the detection of early fungal decay was examined. The HEMI test characterises the treatment severity of thermally modified wood by stressing the treated material by thousands of impacts of pounding steel balls. This method differentiates between heat treatment intensities, which are manifest as structural changes in the wood. Similar changes in wood structure are known for wood decayed by fungi. Pine (Pinus sylvestris L.) decayed by brown rot and beech (Fagus sylvatica L.) decayed by white rot were tested. Mass loss caused by fungal decay and resistance to impact milling (RIM) determined in HEMI tests were found to be highly correlated. Testing of non-degraded pine, beech, and ash (Fraxinus exelsior L.) showed only marginal effects of wood density on RIM. Furthermore, annual ring angles and RIM of spruce (Picea abies Karst.) were not correlated. Accordingly, the detection of RIM reduction in decayed wood is not masked by variations in density and orientation of the annual rings. Previous results showed no adverse effects of weathering on RIM. Thus, the detection of fungal decay with HEMI tests is feasible not only for laboratory purposes, but also for wood in outdoor applications that has already undergone weathering.

Structural changes in titanium dioxide nanocrystals during plastic deformation

2005 ◽  
Vol 38 (5) ◽  
pp. 749-756 ◽  
Author(s):  
Ulrich Gesenhues
Keyword(s):  
Structural Changes ◽  
Crystal Size ◽  
Lower Layer ◽  
High Energy ◽  
Primary Crystal ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Hall Method ◽  
Means Of Transmission

The polygonization of 200 nm rutile crystals during dry ball-milling at 10gwas monitored in detail by means of transmission electron microscopy (TEM) and X-ray diffraction (XRD). The TEM results showed how to modify the Williamson–Hall method for a successful evaluation of crystal size and microstrain from XRD profiles. Macrostrain development was determined from the minute shift of the most intense reflection. In addition, changes in pycnometrical density were monitored. Accordingly, the primary crystal is disintegrated during milling into a mosaic of 12–35 nm pieces where the grain boundaries induce up to 1.2% microstrain in a lower layer of 6 nm thickness. Macrostrain in the interior of the crystals rises to 0.03%. The pycnometrical density, reflecting the packing density of atoms in the grain boundary, decreases steadily by 1.1%. The results bear relevance to our understanding of plastic flow and the mechanism of phase transitions of metal oxides during high-energy milling.

Modification of Barium Cerate by Heavy Ion Irradiation

2013 ◽  
Vol 781-784 ◽  
pp. 357-361 ◽  
Author(s):  
Igor V. Khromushin ◽  
Taтiana I. Aksenova ◽  
Turgora Tuseyev ◽  
Karlygash K. Munasbaeva ◽  
Yuri V. Ermolaev ◽  
...  
Keyword(s):  
Structural Changes ◽  
Solid Phase ◽  
Ion Irradiation ◽  
Heavy Ion ◽  
High Energy ◽  
Low Energy ◽  
Barium Cerate ◽  
Weakly Bound ◽  
Ion Ranges ◽  
High Energy Ions

The effect of irradiation with heavy ions Ne, Ar, and Kr of various energies on the structure and properties of ceramic barium cerate doped with neodymium and annealed in air at 650°C for 7 hours is studied. It is noted that blistering was observed on cerate surface during its irradiation by low energy Ne ions, whereas it was not observed under low-energy Ar and Kr ions irradiation. Irradiation of the cerate with high energy ions caused partial amorphization of the irradiated surface of the material, while the structure of the non-irradiated surface did not change. In addition, the irradiated surface of the cerate endured solid-phase structural changes. Thus, upon high-energy ions irradiation in the range of Ne, Ar, Kr the cerate surface resembled the stages of spherulite formation - nucleation, growth (view of cauliflower), formation of spherulitic crust, respectively. The increase in water molecules release and reduction of molecular oxygen release from the barium cerate, irradiated by high-energy ions is found during vacuum constant rate heating. It is concluded that cerates undergo changes to the distances significantly exceeding the ion ranges in these materials. Features of high-energy ions influence on thermal desorption of carbon dioxide from cerates show, apparently, the formation of weakly bound carbonate compounds on the cerate surface in the irradiation process.

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