Jānis Grabis. Plasma chemical synthesis of multicomponent nanopowders, their characteristics, and processing

Transcription

1 Jānis Grabis Plasma chemical synthesis of multicomponent nanopowders, their characteristics, and processing

2 Outline Introduction nanoparticles, their preparation methods Experimental synthesis of multicomponent nanoparticles by using RF plasma characteristic features of produced particulate composites processing by hot pressing and SPS sintering. Conclusions

3 Nanostructured materials Engine parts Cutting tools High -temperature ceramics Advanced coatings Polymer matrix composites Metal -matrix composites Nanoparticles Nanotechnology, nanowires, thin films, carbon nanotubes Electronics Optoelectronic devices Phosphorus Multilayer capacitors Manomagnetic fluids Data storage Energy storage Sensors Fuel cells Nano - biotechnology Biomaterials, implants Antimicrobial wound dressing Drug delivery Human health monitoring Nano -systems Catalysts Chemical sensors Pigments UV radiation protection Abrasion, corrosion protection Reinforcement, fillers Flame retardants Self -learning glasses, textiles Propellants Application of nanoparticles

4 Preparation methods of nanoparticles Mechanical solid state phase processing Liquid phase processing Mechanical milling Mechanical alloying Mechanical-chemical processing Plastic deformation Sol-gel processing Chemical hydroxide precipitation Hydrothermal synthesis Combustion synthesis Gas phase processing Inert gas condensation Laser synthesis DC, RF, microwave plasma synthesis

5 Application of multicomponent nanoparticles Improvement of mechanical, physical and chemical characteristics Preparation of uniform mixtures of refractory compounds with sintering additives Catalysts Doped nanoparticles for microelectronics and luminiscent materials

6 Plasmachemical synthesis based on formation of product from a vapour phase provides an attractive alternative for producing multicomponent compounds or particulate composites due to mixing of component at molecular level and relative high production rate of a simple one-stage process.

7 Plasma apparatus for producing nanoparticles Institute of Inorganic Chemistry RTU P P powder N 2 NH 3 H 2O P N 2 reactor RF coil heat exchanger filter RF plate power kw Frequency 5.28 or 1.2 MHz Plasma forming gas flowrate m 3 /h Quenching gas flowrate m 3 /h Feeding rate of powders kg/h

8 Necessary conditions for preparation of nanosized powders of refractory compounds 1. Complete evaporation of raw materials determined by: - plasma parameters and temperature distribution - particle size of raw materials and their injection mode 2. Controlled growth rate and time of product particles determined by: - concentration of particles in plasma flow - melting and boiling temperature of product particles - cooling rate of products - velocity of plasma flow - ratio and quantity of products components 3. Elimination growth of precursor particles or extra phases started at higher temperature and promotion formation of product particles by changing temperature and reaction agents

9 Characteristics of prepared nitride-based particulate composites Reactants Ti, Ni, Co, Fe, N 2 Ti, Cr, W, N 2 SSA, m 2 /g Products Phase compositions Nitride-Metal TiN, Ni, Co, Fe TiN, Cr, Cr 2 N, W Ti, Mo, N TiN, Mo, Mo 2 N Al, Mo, N Al, Cr, Fe, N Ti, Al, N 2, NH Zr, Al, N 2, NH Al, Si, NH 3, N 2 Ti, Si, NH 3, N 2 Zr, Si, NH 3, N AlN, Mo AlN, Cr 2 N, Cr, Fe Nitride-Nitride TiN, AlN ZrN, AlN AlN, Si 3 N 4 TiN, Si 3 N 4 ZrN, Si 3 N 4 Morphology of particle TiN cubic crystals coated with metal droplets TiN rod-like particles AlN whiskers with Mo, Cr, Fe, Cr 2 N droplets TiN or ZrN cubic crystals coated with AlN AlN, TiN or ZrN crystals coated with Si 3 N 4 Reactants SSA, m 2 /g Phase compositions Nitride-Carbide Products Morphology of particle Si, CH 4, NH 3, N Si 3 N 4, SiC SiC particles coated with Si 3 N 4 Ti, CH 4, N TiN 0.6 C 0.4 Cubic particles W, CH 4, N W 2 C, WC 1-x Nitride-Fluoride Al, CaF 2, NH 3, N Al, YF 3, NH 3, N Al, CaO, NH 3, N Al, Y 2, NH 3, N Si, Y 2, Al 2, NH 3, N 2 Si, SiO 2, Al, Al 2, N 2, NH AlN, CaF 2 AlN, YF 3 Nitride-Oxide AlN, CaO AlN, Y 2, YN Si 3 N 4, Y 2, Al 2, YSi 2 β-si 6-x Al x O x N 8-x AlN hexagonal plates, CaF 3, YF 3 spherical particles AlN hexagonal plates, CaO, Y 2 spherical particles Unregular-shaped particles

10 Characteristics of nanosized oxides and their composites Raw powders As prepared After annealing SSA, m 2 /g Phase composition T, o C SSA, m 2 /g Phase composition ZrO 2, Y t-zro 2, m-zro 2, c-zro t-zro 2, m-zro 2, c-zro 2 Al 2 O, ZrO 2, Y δ-al 2, t-zro 2, m-zro α-al 2, t-zro 2, m-zro 2 3Al 2.2SiO 2 -ZrO 2 33 m-, t-zro Al 2.2SiO 2, m-, t-zro 2 NiO, ZrO 2, Y NiO, t-, c-zro NiO, c-zro 2 Al 2, Ni5-56 NiAl 2 O 4, NiO NiAl 2 O 4, NiO Al 2, Mg5-60 MgAl 2 O MgAl 2 O 4 Al 2, Si5-48 X-ray amorph Al 2 *2SiO 2, δ-al 2 Al 2, Co0-48 CoAl 2 O 4, Co 2 Al 2 O CoAl 2 O 4, Co 2 Al 2 O 4 Al-Na-Li-O β-,β -Al 2, Al(OH) 3, m- Al β - Al 2, β-al 2 (tr.) Fe 2, NiO NiFe 2 O 4 Zn-O, Eu ZnO CoO, Fe2 CoFe 2 O 4.

11 Main features of multicomponent powders Formation of coated particles Change of chemical characteristics Change of particle shape Change of phase composition Dependence of specific surface area and particle size on the ratio of components

12 Micrographs of particles ZrO 2 -Al 2 ZrO 2 -Al 2 ZrO 2 -Al 2 Al 2 -SiO 2 TiN-Mo AlN-Mo TiN-Ni

13 Z-potential curves of ZrO 2, ZrO 2 -Al 2, and Al ZrO AlZr1 2 /75,9% Al 2 (1) 80 (4) ZrO AlZr2 2 /48,8% Al 2 (2) 60 (3) (1) ZrO AIZr3 2 /29,4% Al 2 (3) Al2O3 δ-,θ-al 9962f 2 (4) Z-potential, mv t-, ZrO2 m-zro 921IV 2 (5) (5) (2) ph

14 Dependence of oxidation temperature of particulate composites on content of the second phase 1000 Oxidation temperature, o C TiN-Si 2 N 4 ZrN-AlN TiN-AlN AlN-Ni Content of the second phase, wt.%

15 Dependence of crystallite size and content of m-zro 2 phase on the contentration of Al 2 m-zro 2 m-zro 2 t-zro 2

16 Dependence of SSA of particulate nanocomposites powders on the content of second phase 60 Specific surface area, m 2 /g AlN-Si 3 N 4 Al 2 -MgO TiN-AlN Al 2 -ZrO 2 TiN-MO Content of the second component, %

17 Densification methods of nanoparticles Pressing Injection molding Conventional methods: Hot pressing Sintering Electrophorestic deposition Ink printing Fast sintering methods: Microwave Spark plasma Laser

18 Sintering methods Nanoparticles are consolidated by using hot pressing at o C by using spark plasma sintering (SPS, Sojitz Corp.) technique at o C; applied pressure of 30 MPa is selected and maintained constant

19 WC hot pressing process parameters Temperature, o C; srinkage, mmx200; srinkage rate, mm/minx500 Temperature, o C Shrinkage Shrinkage rate Time

20 Microstructure of hot-pressed WC HP73_WC 1800 o C/1 h

21 Parameters of SPS process of YAG nanopowders Temperature, o C Displacement (s), mm Displacement Temperature ds/dt, mm/s 00: : : : : : : : : : : : : : : : :00.00 Time (t), min

22 SEM images of fracture surface of Y3Al5O12 samples Spark plasma sintering Conventional pressureless sintering

23 Conclusions 1. Plasmachemical synthesis have been applied successfully for producing nitride-metals, nitride-carbide, nitride-oxide, oxideoxide, oxide-metals particulate nanocomposites by introducing and evaporation of coarse-grained commercially available powders of chemical elements, oxides, and salts in nitrogen or air plasma. 2. Synthesis of multicomponent particulate composites in thermal plasma influences particle shape, phase composition, specific surface area with respect to single particle. 3. Spark plasma sintering of the multicomponent particulate nanocomposites intensifies densification with respect to hot pressing or pressureless sintering but also accelerates grain growth.

24 THANK YOU!