scholarly journals Mechanochemical Activation and Spark Plasma Sintering of the Lead-Free Ba(Fe1/2Nb1/2)O3 Ceramics

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2254
Author(s):  
Dariusz Bochenek ◽  
Joanna A. Bartkowska ◽  
Lucjan Kozielski ◽  
Izabela Szafraniak-Wiza
Keyword(s):  
Dielectric Properties ◽  
Technological Process ◽  
Milling Time ◽  
Mechanochemical Activation ◽  
Perovskite Phase ◽  
High Energy ◽  
Lead Free ◽  
Electric Permittivity ◽  
Plasma Sintering ◽  
Spark Plasma

This paper investigates the impact of the technological process (Mechanochemical Activation (MA) of the powder in combination with the Spark Plasma Sintering (SPS) method) on the final properties of lead-free Ba(Fe1/2Nb1/2)O3 (BFN) ceramic materials. The BFN powders were obtained for different MA duration times (x from 10 to 100 h). The mechanically activated BFN powders were used in the technological process of the BFN ceramics by the SPS method. The measurements of the BFNxMA ceramic samples included the following analysis: Scanning Electron Microscopy (SEM), Energy Dispersive Spectrometry (EDS), DC electrical conductivity, and dielectric properties. X-ray diffractions (XRD) tests showed the appearance of the perovskite phase of BFN powders after 10 h of milling time. The longer milling time (up 20 h) causes the amount of the perovskite phase to gradually increase, and the diffraction peaks are more clearly visible. Short high energy milling times favor a large heterogeneity of the grain shape and size. Increasing the MA milling time to 40 h significantly improves the microstructure of BFN ceramics sintered in the SPS technology. The microstructure becomes fine-grained with clearly visible grain boundaries and higher grain size uniformity. Temperature measurements of the BFN ceramics show a number of interesting dielectric properties, i.e., high values of electric permittivity, relaxation properties with a diffusion phase transition, as well as negative values of dielectric properties occurring at high temperatures. The high electric permittivity values predestines the BFNxMA materials for energy storage applications e.g., high energy density batteries, while the negative values of dielectric properties can be used for shield elements against the electromagnetic radiation.

Spark Plasma Sintering of High-Energy Ball-Milled ZrB2 and HfB2 Powders with 20vol% SiC

2018 ◽  
Vol 941 ◽  
pp. 1990-1995
Author(s):  
Naidu V. Seetala ◽  
Cyerra L. Prevo ◽  
Lawrence E. Matson ◽  
Thomas S. Key ◽  
Ilseok I. Park
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Ball Milling ◽  
Milling Time ◽  
High Energy ◽  
Micro Hardness ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Energy Ball ◽  
Ball Milling Time

ZrB2 and HfB2 with incorporation of SiC are being considered as structural materials for elevated temperature applications. We used high energy ball milling of micron-size powders to increase lattice distortion enhanced inter-diffusion to get uniform distribution of SiC and reduce grain growth during Spark Plasma Sintering (SPS). High-energy planetary ball milling was performed on ZrB2 or HfB2 with 20vol% SiC powders for 24 and 48 hrs. The particle size distribution and crystal micro-strain were examined using Dynamic Light Scattering Technique and x-ray diffraction (XRD), respectively. XRD spectra were analyzed using Williamson-Hall plots to estimate the crystal micro-strain. The particle size decreased, and the crystal micro-strain increased with the increasing ball milling time. The SPS consolidation was performed at 32 MPa and 2,000°C. The SEM observation showed a tremendous decrease in SiC segregation and a reduction in grain size due to high energy ball milling of the precursor powders. Flexural strength of the SPS consolidated composites were studied using Four-Point Bend Beam test, and the micro-hardness was measured using Vickers micro-indenter with 1,000 gf load. Good correlation is observed in SPS consolidated ZrB2+SiC with increased micro-strain as the ball milling time increased: grain size decreased (from 9.7 to 3.2 μm), flexural strength (from 54 to 426 MPa) and micro-hardness (from 1528 to 1952 VHN) increased. The correlation is less evident in HfB2+SiC composites, especially in micro-hardness which showed a decrease with increasing ball milling time.

Improving Mechanical Properties of Ceramic Composites by Harmonic Microstructure Control

2014 ◽  
Vol 896 ◽  
pp. 570-573 ◽  
Author(s):  
Lydia Anggraini ◽  
Ryohei Yamamoto ◽  
Kazuma Hagi ◽  
Hiroshi Fujiwara ◽  
Kei Ameyama
Keyword(s):  
Mechanical Properties ◽  
Milling Time ◽  
Milled Powder ◽  
High Energy ◽  
Ceramic Composites ◽  
Design Tool ◽  
Powder Mixtures ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Relationship Of

In this research, several ceramic composites such as SiC-ZrO2, Al2O3-ZrO2, and Si3N4-ZrO2containing nominally equal ratio 1:1 were prepared through high energy mechanical milling and spark plasma sintering. The relationship of microstructure and mechanical properties were investigated. Harmonic microstructures consisting of fine and ultra-fine grains forming a network were obtained by the optimum milling time for 144ks with high mechanical properties. The non-milled powder mixtures and too long milling time powder mixtures have low mechanical properties sintered by spark plasma. The crack propagates through ultra-fine grains and deflected by larger fine grains were obtained on the harmonic microstructure sample resulting in high toughness. Thus, the harmonic microstructure can be considered a remarkable design tool for improving the mechanical properties of SiC-ZrO2, Al2O3-ZrO2, and Si3N4-ZrO2as well as other ceramic composites.

Mechanical Properties of Ti-Nb-X-CPP Biomaterial Fabricated by Spark Plasma Sintering

2011 ◽  
Vol 399-401 ◽  
pp. 1592-1595
Author(s):  
Kee Do Woo ◽  
Sang Hoon Park ◽  
Ji Young Kim ◽  
Sang Mi Kim ◽  
Dong Soo Kang
Keyword(s):  
Elastic Modulus ◽  
Spark Plasma Sintering ◽  
Milling Time ◽  
Raw Materials ◽  
High Energy ◽  
X Ray Diffraction ◽  
Increase Milling Time ◽  
Plasma Sintering ◽  
Low Elastic Modulus ◽  
Spark Plasma

Ti-6Al-4V ELI (Extra Low Interstitial) alloy have been widely used as alternative bone due to its excellent biocompatibility, although it still has many problems such as high elastic modulus and toxic. Therefore, biomaterial with low elastic modulus and nontoxic has to be developed. In this study, the raw materials which are nontoxic elements such as Nb and Mo were mixed and milled in a mixing machine (24h) and a high energy mechanical ball milling machine (1h, 4h and 8h) respectively. Ti-Nb-Mo-CPP composites were fabricated by spark plasma sintering (SPS) at 1000°C under 70MPa using mixed and milled powders. The effects of CPP contents and milling time on biocompatibility and mechanical property have been investigated. By X-ray diffraction (XRD), chemical reaction during the sintering was occurred and revealed new phases, Ti2O, CaO, CaTiO3, and TixPy. Vickers hardness of composites increases with increase milling time and addition of HA contents. Biocompatibility of HA added Ti-Nb-Si alloys were improved.

scholarly journals Microstructure And Thermoelectric Properties Of Tags-90 Compounds Fabricated By Mechanical Milling Process

2015 ◽  
Vol 60 (2) ◽  
pp. 1231-1234 ◽  
Author(s):  
H.-S Kim ◽  
M. Babu ◽  
S.-J. Hong
Keyword(s):  
Thermoelectric Properties ◽  
Milling Time ◽  
Fine Particles ◽  
High Energy ◽  
Dispersion Analysis ◽  
Milling Process ◽  
X Ray Diffraction ◽  
Fine Grain ◽  
Plasma Sintering ◽  
Spark Plasma

Abstract TAGS-90 compound powder was directly prepared from the elements by high-energy ball milling (HEBM) and subsequently consolidated by a spark plasma sintering (SPS). Effect of milling time on the microstructure and thermoelectric properties of the samples were investigated. The particle size of fabricated powders were decreased with increasing milling time, finally fine particles with ~1μm size was obtained at 90 min. The SPS samples exhibited higher relative densities (>99%) with fine grain size. X-ray diffraction analysis (XRD) and energy dispersion analysis (EDS) results revealed that all the samples were single phase of GeTe with exact composition. The electrical conductivity of samples were decreased with milling time, whereas Seebeck coefficient increased over the temperature range of RT~450°C. The highest power factor was 1.12×10−3W/mK2 obtained for the sample with 90 min milling at 450°C.

Effect of Milling and Calcium Phosphate on Mechanical Properties of Nanostructured TiNbMo/CPP Biocomposites

2012 ◽  
Vol 452-453 ◽  
pp. 12-15
Author(s):  
Kee Do Woo ◽  
Sang Hoon Park ◽  
Ji Young Kim
Keyword(s):  
Elastic Modulus ◽  
Milling Time ◽  
Raw Materials ◽  
High Energy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Increase Milling Time ◽  
Plasma Sintering ◽  
Low Elastic Modulus ◽  
Spark Plasma

Ti-6Al-4V ELI (Extra Low Interstitial) alloy have been widely used as alternative bone due to its excellent biocompatibility, although it still has many problems such as high elastic modulus and toxic. Therefore, biomaterial with low elastic modulus and nontoxic has to be developed. In this study, the raw materials which are nontoxic elements such as Nb and Mo were mixed and milled in a mixing machine (24h) and a high energy mechanical ball milling machine (1h, 4h and 8h) respectively. Ti-Nb-Mo-CPP composites were fabricated by spark plasma sintering (SPS) at 1000°C under 70MPa using mixed and milled powders. The effects of CPP contents and milling time on biocompatibility and mechanical property have been investigated. By X-ray diffraction (XRD), chemical reaction during the sintering was occurred and revealed new phases, Ti2O, CaO, CaTiO3, and TixPy. Vickers hardness of composites increases with increase milling time and addition of CPP contents. Biocompatibility of CPP added Ti-Nb-Mo alloys were improved.

Effect of High-Energy Ball-Milling and TiB2 Content on Microstructures and Properties of Cu-TiB2 Composites Sintered by SPS

2006 ◽  
Vol 118 ◽  
pp. 661-665 ◽  
Author(s):  
Dae Hwan Kwon ◽  
Thuy Dang Nguyen ◽  
Pyuck Pa Choi ◽  
Ji Soon Kim ◽  
Young Soon Kwon
Keyword(s):  
Electrical Conductivity ◽  
Ball Milling ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Energy Ball ◽  
Xrd Patterns ◽  
Short Time ◽  
Tib2 Particles

The microstructure and properties of Cu-TiB2 composites produced by high-energy ball-milling of TiB2 powders and spark-plasma sintering (SPS) were investigated. TiB2 powders were mechanically milled at a rotation speed of 1000rpm for short time in Ar atmosphere, using a planetary ball mill. To produce Cu-xTiB2 composites( x = 2.5, 5, 7.5 and 10wt.% ), the raw and milled TiB2 powders were mixed with Cu powders by means of a turbular mixer, respectively. Sintering of mixed powders was carried out in a SPS facility under vacuum. High-energy ball-milling resulted in refinement of TiB2 particles. XRD patterns of milled TiB2 powders indicated broader TiB2 peaks with decreased intensities. After sintering at 950 for 5min using the raw and milled TiB2 mixture powders, the sintered density decreased with increasing TiB2 content regardless of milling of TiB2. In the case of raw TiB2, hardness rapidly increased from 4 to 44 HRB with increasing TiB2 content. The electrical conductivity changed from 95.5 to 80.7 %IACS. For mixtures of Cu powders with milled TiB2 powders, hardness increased from 38 to 67 HRB as TiB2 content increased, while the electrical conductivity varied from 88% to 51 % IACS. When compared to compacts sintered with raw and milled TiB2 powders, the electrical conductivity of specimens with raw TiB2 powder was higher than that of specimens with milled TiB2 powder, while hardness was slightly lower.

Dielectric properties of fine-grained BaTiO3 prepared by spark-plasma-sintering

2004 ◽  
Vol 83 (1) ◽  
pp. 23-28 ◽  
Author(s):  
Baorang Li ◽  
Xiaohui Wang ◽  
Longtu Li ◽  
Hui Zhou ◽  
Xingtao Liu ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Spark Plasma Sintering ◽  
Fine Grained ◽  
Plasma Sintering ◽  
Spark Plasma
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