Nanostructured composite powders for producing protective coatings of machinebuilding parts and units

2021 ◽  
pp. 52-59
Author(s):  
E. Yu. Gerashchenkova ◽  
T. I. Bobkova ◽  
E. A. Samodelkin ◽  
D. A. Gerashchenkov ◽  
A. F. Vasiliev ◽  
...  
Keyword(s):  
Titanium Nitride ◽  
Protective Coatings ◽  
Promising Method ◽  
Metal System ◽  
Ball Mills ◽  
Composite Powders ◽  
Nanostructured Composite ◽  
Economical Performance

The paper studies a method for producing nanostructured composite powders of the metal – non-metal system. Powders preparation by universal disintegrator-activator technology, processing in planetary ball mills and bowl grinders is shown on the Al–Zn–Sn composition and titanium nitride nanoparticles. Judging by engineering-and-economical performance, the most promising method for obtaining nanostructured composite powders is the method of processing in a bowl grinder.

MICROSTRUCTURE AND MAGNETIC PROPERTIES OF NANOSTRUCTURED Al2O3-20vol%Fe70Co30 COMPOSITE PREPARED BY HIGH ENERGY MECHANICAL MILLING

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1383-1388 ◽  
Author(s):  
MASLEEYATI YUSOP ◽  
DELIANG ZHANG ◽  
MARCUS WILSON ◽  
NICK STRICKLAND
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Alloy Powder ◽  
Milling Time ◽  
High Energy ◽  
Composite Powders ◽  
Nanostructured Composite ◽  
Alloy Particles ◽  
Average Grain Size ◽  
Microstructure And Magnetic Properties

Al 2 O 3-20 vol % Fe 70 Co 30 composite powders have been prepared by high energy ball milling a mixture of Al 2 O 3 powder and Fe 70 Co 30 alloy powder. The Fe 70 Co 30 alloy powder was also prepared by mechanical alloying of Fe and Co powders using the same process. The effects of milling duration from 8 to 48 hours on microstructure and magnetic properties of the nanostructured composite powders have been studied by means of X-ray Diffractometry (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometry (VSM). It was found that the nanostructured composite powder particles with irregular shapes and Fe 70 Co 30 alloy particles being embedded in them formed after 8 hours of milling. The average grain size of the Al 2 O 3 matrix reduced drastically to less than 18nm after 16 hours of milling. On the other hand, the embedded alloy particles demonstrated almost unchanged average grain size in the range of 14-15nm. Magnetic properties of the powder compacts at room temperature were measured from hysteresis curves, and show strong dependence of the milling time, with the coercivity increasing from 67.1 up to 127.9kOe with increasing the milling time from 8 to 48 hours. The possible microstructural reasons for this dependence are discussed.

scholarly journals Combined Application of Composite Powders WC-Co and Additives of Nanoparticles as an Effective Method of Improving the Properties of Hard Metals

2018 ◽  
Vol 769 ◽  
pp. 134-140 ◽  
Author(s):  
Yuri I. Gordeev ◽  
Vitaly B. Yasinski ◽  
Aleksandr S. Binchurov ◽  
Nikolay E. Anistratenko ◽  
Irina V. Nikolaenko
Keyword(s):  
Intergranular Crack ◽  
Experimental Studies ◽  
Physical And Mechanical Properties ◽  
Hard Metal ◽  
Composite Powders ◽  
Nanostructured Composite ◽  
Combined Application ◽  
Hard Metals ◽  
Microstructure Parameters ◽  
Carbide Particles

The results of experimental studies show that the use of composite powders (WC-Co) in combination with the modification by the additives of ceramic nanoparticles allows controlling the parameters of the microstructure and increasing the strength of the binder and the level of physical and mechanical properties of the hard metal in general. The coating of carbide particles with a layer of a binder is an effective starting method that allows to obtain a bulk compound that preserves the unique properties of the initial nanopowders and ensures a uniform distribution of the phases (WC, Co, Al2O3). Such multiphase fragmentary nanostructured composite is characterized by additional heterogeneity, determined by the differences in size and elastic properties of the phases. By combining the sizes and properties of the phase components in such heterogeneous composite, it is possible to increase the fracture energy (i.e. Palmqvist fracture toughness) up to 20 - 22 MPa∙m1/2 as a result of inhibition on inclusions of nanoparticles the stress relaxation and change in the trajectory of the intergranular crack. Based on the proposed stereological models and experimentally established relationships between composition and microstructure parameters, the required volume concentrations of nanoparticles’ additives and composite powders (WC-Co) were determined.

Synthesis and Processing of Nanograined Fe - (Fe, Mo)6C Composite Powders

1994 ◽  
Vol 351 ◽  
Author(s):  
R. K. Sadangi ◽  
B. H. Kear ◽  
L. E. McCandlish
Keyword(s):  
High Speed ◽  
Volume Fraction ◽  
High Volume ◽  
Processing Parameters ◽  
Precursor Powder ◽  
Water Soluble ◽  
Thermochemical Conversion ◽  
Composite Powders ◽  
Nanostructured Composite ◽  
Spray Conversion

ABSTRACTSpray Conversion Processing was used to synthesize high volume fractions (0.52 - 0.74) of nanograined (Fe, Mo)6C carbide dispersions in iron, starting from water soluble precursors. The essential features of the process are, (1) preparation of a chemically homogeneous precursor powder, and (2) thermochemical conversion of the precursor powder to the desired nanostructured composite powder through controlled gas-solid reactions. The thermodynamic and kinetic features of the gas-solid reactions, and the influence of various processing parameters on the structures developed, are discussed. The powders were consolidated to near theoretical density by pressureless sintering and hot pressing. All the consolidated samples had bicontinuous structures. Compared to M2 high speed tool steels, these high volume fraction carbide strengthened iron alloys display superior hardness values up to 500°C.

Design and Processing of Novel Ceramic Composite Structures for Use in Medical Surgery

2017 ◽  
Vol 750 ◽  
pp. 195-204
Author(s):  
Marta Fornabaio ◽  
Paola Palmero ◽  
Helen Reveron ◽  
Jérôme Chevalier ◽  
Laura Montanaro
Keyword(s):  
Mechanical Properties ◽  
Composite Structures ◽  
Ceramic Composite ◽  
Optical Microscope ◽  
Medical Surgery ◽  
Composite Powders ◽  
Bending Tests ◽  
Nanostructured Composite ◽  
Second Phases ◽  
Dental Applications

. In order to fulfill the clinical requirements for strong, tough and stable ceramics for dental applications, we have designed and developed innovative Ceria-stabilized zirconia (Ce-TZP)-based composites. In particular, we have added two kinds of second phases to the Ce-TZP matrix: equiaxed a-Al2O3 grains, for increasing the hardness and the fracture strength, and elongated hexa-aluminates (both SrAl12O19 and CeMgAl11O19), to provide an additional toughening effect by crack deflection/bridging mechanisms. In order to carefully control the composition and the microstructure in those complex composite systems, we have used a novel surface-coating approach for the preparation of the nanostructured composite powders, which allows a perfect tailoring of the microstructural, morphological and compositional features of the composites. Once optimized the sintering cycle for each composite material, both composites reached full densification. Mechanical properties (Vickers hardness, flexural strength and fracture toughness) were evaluated, while the zirconia transformability was followed by means of an optical microscope during load-unload bending tests. The sensitivity to ageing was estimated by autoclave treatments. In spite of a remarkable different behavior – mainly in terms of stress-induced tetragonal to monoclinic zirconia transformability - both materials showed excellent mechanical properties as well as a negligible sensitivity to ageing, thus demonstrating their high potential for new reliable and safe devices for structural biomedical applications.

Processing of Chromium Silicide-Silicon Carbide Nanostructured Composite by Thermal Conversion of Spray Dried Precursor Powders

1992 ◽  
Vol 286 ◽  
Author(s):  
Ping Luo ◽  
P. I. Strutt
Keyword(s):  
Silicon Carbide ◽  
Silicon Oxide ◽  
Thermal Conversion ◽  
Lattice Parameter ◽  
Composite Powders ◽  
Nanostructured Composite ◽  
Chromium Silicide ◽  
Precursor Powders ◽  
Chemical Synthesis Route ◽  
Spray Dried

ABSTRACTA new group of nanostructured composites with chromium silicide and silicon carbide has been developed. These composite powders which are about 20-40 rm in size were prepared by the chemical synthesis route and were characterized by UV, DTA/TGA, XRD, FTIR and SEM. Chemical reaction and phase formation versus the processing temperatures have been investigated and discussed. The particle size and the lattice parameter of the synthesized composite have been found to be dependent on the processing temperatures. A possible reaction mechanism of the nanostructured silicon oxide to silicon carbide is proposed.

Study of the formation of nanostructured composite powders in a plasma jet

2019 ◽  
Vol 26 (5) ◽  
pp. 739-744 ◽  
Author(s):  
V. O. Drozdov ◽  
A. E. Chesnokov ◽  
A. N. Cherepanov ◽  
A. V. Smirnov
Keyword(s):  
Plasma Jet ◽  
Composite Powders ◽  
Nanostructured Composite

Modifying structure and properties of nickel alloys by nanostructured composite powders

2015 ◽  
Vol 22 (1) ◽  
pp. 127-132 ◽  
Author(s):  
A. N. Cherepanov ◽  
V. E. Ovcharenko ◽  
G. Liu ◽  
L. Cao
Keyword(s):  
Nickel Alloys ◽  
Structure And Properties ◽  
Composite Powders ◽  
Nanostructured Composite

Synthesis and Nanocomposite Sintering of Hydroxyapatite-Coated Zirconia Nanopowders

2006 ◽  
Vol 49 ◽  
pp. 68-73
Author(s):  
Federica Bondioli ◽  
Valeria Cannillo ◽  
Luca Lusvarghi ◽  
Tiziano Manfredini ◽  
Anna Maria Ferrari
Keyword(s):  
Composite Powder ◽  
Aqueous Suspension ◽  
Morphological Properties ◽  
Composite Powders ◽  
Nanostructured Composite ◽  
Bioactive Properties ◽  
Implant Material ◽  
Zirconia Nanopowders ◽  
Sintered Materials

Hydroxyapatite (HAP), Ca10(PO4)6(OH)2, is a well-known and a valuable implant material with biocompatibility and bioactive properties. Full utilisation of the unique properties of hydroxyapatite bulk ceramics is, however, enhanced by a proper reinforcement, i.e. by preparation of composites. The goal of this study was to synthesize a HAP-coated zirconia composite powder by the precipitation of HAP in presence of zirconia. The idea was to avoid uncontrolled agglomeration of the zirconia nanostructured reinforcement during the sintering step. ZrO2 nanopowders, previously synthesized by hydrothermal crystallisation, were added in an appropriate amount to an intensively stirred aqueous suspension of Ca(OH)2. HAP was precipitated by addition of H2PO4 at controlled pH in order to obtain a 50:50 composite powders. The obtained powders, fully characterized by TEM, XRD, TG-DTA and BET, were used for the preparation of the nanostructured composite speciments. The sintered materials were characterized in order to evaluate their structural and morphological properties.

Reinforcing and toughening alumina/titania ceramic composites with nano-dopants from nanostructured composite powders

2009 ◽  
Vol 508 (1-2) ◽  
pp. 161-166 ◽  
Author(s):  
Yong Yang ◽  
You Wang ◽  
Wei Tian ◽  
Zhen-qiang Wang ◽  
Yue Zhao ◽  
...  
Keyword(s):  
Ceramic Composites ◽  
Composite Powders ◽  
Nanostructured Composite
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