Nanopowder mixtures of ASM5 0.1/0 diamond, and WO₃ were formed in the liquid. Air drying and thermal treatment of these mixtures in hydrogen were carried out. Composites were HP sintered from them [1, 2]. The structure and phase composition of the mixtures and sintered composites have been studied.

The WO₃ particle size is in the range of 150–250 nm, the particles are fragmented, the grain size varies from 10 to 150 nm. The size of the diamond particles does not exceed 100 nm. The relative position of the particles of diamond and WO₃ is homogeneous enough, however, a tendency to agglomerate particles is observed (fig. 1).

Fig. 1. The structure of the mixture of ASM5 0.1/0 statically synthesized diamond nanopowder and tungsten trioxide powder (46%) formed in a liquid after drying before annealing in hydrogen

 During the mixture heat treatment in hydrogen at the temperature of 900 °C the complete recovery of WO₃ to the metal tungsten occurs. In case of deviation from the heat treatment the W₃O oxide is present in the mixture, together with metallic tungsten and WO₂. The particle size of formed tungsten increased by 2–3 times compared to the WO₃ precursor particles (fig. 2). The formed particles are less fragmented.

a

b

Fig. 2. Structure of the mixture of diamond nanopowder and tungsten trioxide after annealing in hydrogen obtained by SEM  at different magnifications (a, b)

 The diamond and WC are the main phases in the composite sintered from the mixture which includes WO₂, apart from diamond and tungsten. A small amount of W and WO₂ is also present. Amount of WO₂ has not changed compared to the initial mixture (fig. 3). WC formed as a result of the diamond and tungsten reaction is in the interspaces between the diamond particles and improves the connection between them (fig. 4). While the presence of WO₂ in the interspaces worsens the connection.

a

b

Fig. 3. Diffractogram (a) and diffraction pattern (b) of composite sintered from a mixture of diamond nanopowder and tungsten powder treatment in hydrogen

Fig. 4. The structure of the surface obtained by shearing the sintered composite sample

 

[1]    S.N. Nazarchuk, A.A. Bochechka, V.S. Gavrilova, L.A. Romanko, N.N. Belyavina, L.I. Alexandrova, V.N. Tkach, E.F. Kuzmenko, S.D. Zabolotnyi, J. Superhard Materials, 2011, vol. 33, no. 1, pp. 1–12.

[2]    M.V. Novіkov, A.A .Bochechka, S.M. Nazarchuk, V.S. Gavrilova, G.S. Oleinik, L.A. Romanko, I.A. Sveshnіkov, S.D. Zabolotny. Patent of Ukraine 93803, Publ. 10.03.11. Byul. 5.

• Legal notice:
  

  Copyright (c) Pielaszek Research, all rights reserved.
  The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
  In every case, proper references including Author(s) name(s) and URL of this webpage: https://science24.com/paper/30196 must be provided.

1. Analysis of density waves in CdSe, SiC, and diamond nanocrystals by application of NanoPDF software package to experimental Pair Distribution Functions.
2. Crystallite size determination from diffraction data: a do-it-yourself tutorial.  
3. High-pressure diffraction study of structural and elastic properties of zircon-type and scheelite-type RVO₄ (R = Nd, Eu)
4. Looking at the real structure of nanocrystals with powder diffraction: the apparent lattice parameter approach
5. Looking beyond limitations of diffraction methods of structural analysis of nanocrystalline materials
6. Growth of GaN layers on silicon and sintered GaN nano-ceramic substrates – TEM investigations
7. Growth and properties of ytterbium doped KY(WO₄)₂ nanocomposites
8. Dyfraktometryczna analiza mikro- i makro-naprężeń w spiekach i kompozytach otrzymanych pod wysokim ciśnieniem i wysoką temperaturą.
9. Badania własności termicznych nanokryształów metodami dyfraktometrycznymi
10. Fabrication and micro-structure characterization of Al2O3/Ni-P composites with interpenetrating phases
11. Nanocrystalline SiC compacts obtained by sintering of laser synthesized nanopowders under extreme pressures
12. High-pressure Induced Structural Decomposition of RE-doped YAG Nanoceramics
13. Sintering of nanopowders under high pressure
14. Synthesis and properties of GaAs nano-composites
15. SiC-Zn nanocomposites obtained using high-pressure infiltration technique
16. Sintering temperature effect on structure and properties of Al2O3/Ni-P composites with interpenetrating phases
17. Structural and luminescence properties of yttrium-aluminum garnet (YAG) nanoceramics
18. Fabrication and electrical properties of Eu³⁺:BaTiO₃ nanoceramics for SOFC
19. X-ray diffraction studies of thermal properties of bulk- and surface-atoms of nanocrystalline SiC
20. Characterization of nanostructured hydroxyapatite ceramics densified at high-pressure and temperature
21. Powder precursors for nanoceramics: cleaning and compaction
22. Examination of the atomic Pair Distribution Function (PDF) of SiC nanocrystals by in-situ high pressure diffraction
23. Investigation of the microstructure of SiC-Zn nanocomposites by microscopic methods: SEM, AFM and TEM
24. Sythesis of metal-ceramic nanocomposites by high-pressure infiltration
25. X-Ray investigations of the natural and artificial White Etching Layer
26. The influence of temperature and pressure on possibility of obtaining Al₂O₃/Ni-P nanocomposite through hot pressing process.
27. X-Ray Characterization of Nanostructured Materials
28. Generetion and Relaxation of Strain in SiC and GaN under Extreme Pressure
29. Influence of high pressure on the polytype structure of nanocrystalline GaN
30. Transformation of fractal microstructure of nanocrystalline SiC and diamond in high pressures - Small Angle Scattering Study
31. Synthesis of Nanocomposites Based on Superhard Ceramic Nanopowders