Spark Plasma Sintering and Characterization of Mixed h-BN Powders with Different Grain Sizes

2018 ◽  
Vol 281 ◽  
pp. 414-419
Author(s):  
Feng Rui Zhai ◽  
Min Lu ◽  
Ke Shan ◽  
Zhong Zhou Yi ◽  
Zhi Peng Xie
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Boron Nitride ◽  
Spark Plasma Sintering ◽  
Hexagonal Boron Nitride ◽  
Orientation Degree ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Crystallization Degree

Mixtures of two grades of hexagonal boron nitride (h-BN) powder differing in their grain size and crystallinity were spark plasma sintering in a vacuum. The influences of the mixing ratio of h-BN powders on the densification, microstructure and mechanical properties were investigated in detail. The results show that the smaller grain size, the lower crystallization degree and the higher density and mechanical properties. While the orientation degree of flake h-BN grains can be greatly enhanced by using h-BN powder with larger particle size. As the increasing of nanometer h-BN powder adding amount, the relative density has the same “V” shape changing trends with mechanical properties. In addition, the orientation of boron nitride grains varied widely, and a nearly isotropic material was prepared from a mixture containing 90wt.% nanometer powder.

Preparation of β SiAlON-cBN Composites by Spark Plasma Sintering

2008 ◽  
Vol 403 ◽  
pp. 241-242
Author(s):  
Mikinori Hotta ◽  
Takashi Goto
Keyword(s):  
Phase Transformation ◽  
Boron Nitride ◽  
Spark Plasma Sintering ◽  
Vickers Hardness ◽  
Hexagonal Boron Nitride ◽  
Cubic Boron Nitride ◽  
Holding Time ◽  
Theoretical Density ◽  
Plasma Sintering ◽  
Spark Plasma

SiAlON-cubic boron nitride (cBN) composite was prepared by spark plasma sintering (SPS) using -SiAlON and cBN powders as starting materials, and the effect of holding time on densification, phase transformation and hardness of the composite was investigated. The SiAlON-cBN composite containing 20 vol% cBN sintered at 1650oC for 60s was densified to >97% of theoretical density. cBN phase transformed to hexagonal boron nitride (hBN) in the SiAlON-cBN composite with increasing holding time at 1650oC. Vickers hardness of the SiAlON-20vol%cBN composite sintered at 1650oC for 60-300s was 17.7GPa, and the hardness decreased with increasing holding time.

scholarly journals Mechanical Properties and Corrosion Resistance of Magnesium–Hydroxyapatite Composites Fabricated by Spark Plasma Sintering

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1314
Author(s):  
Ikuho Nakahata ◽  
Yusuke Tsutsumi ◽  
Equo Kobayashi
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Compressive Strength ◽  
Corrosion Resistance ◽  
Spark Plasma Sintering ◽  
Immersion Test ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Mechanical Properties And Corrosion ◽  
Biodegradable Magnesium

Recent studies indicate that biodegradable magnesium alloys and composites are attracting a great deal of attention in orthopedic applications. In this study, magnesium–hydroxyapatite (Mg–HAP) composites with different compositions and grain size were fabricated by a spark plasma sintering (SPS) method. Their mechanical properties and corrosion behavior in a pseudo-physiological environment were investigated by pH measurements and inductivity coupled plasma (ICP) elemental analysis after an immersion test using Hanks’ solution. The results clearly showed that the addition of HAP improved both the mechanical properties and corrosion resistance. The results also indicated that the finer grain size improved most of the properties that are needed in a material for an orthopedic implant. Furthermore, the authors reveal that there is a strong correlation between the compressive strength and the porosity. In order to achieve the same compressive strength as human bone using these fabrication conditions, it is revealed that the porosity should be lower than 1.9%.

Ultrafine WC-Ni-SiCw Cemented Carbides Fabricated by Spark Plasma Sintering

2012 ◽  
Vol 512-515 ◽  
pp. 924-927
Author(s):  
Hui Yong Rong ◽  
Zhi Jian Peng ◽  
Xiao Yong Ren ◽  
Ying Peng ◽  
Cheng Biao Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Flexural Strength ◽  
Spark Plasma Sintering ◽  
Cemented Carbides ◽  
Plasma Sintering ◽  
Mean Grain Size ◽  
Spark Plasma ◽  
The Mean ◽  
Inhomogeneous Microstructure

Ultrafine WC-Ni cemented carbides with addition of SiC whisker (SiCw) were fabricated by spark plasma sintering. The microstructure and mechanical properties of the fabricated cemented carbides were investigated. It was found that the addition of SiC whisker had no obvious influence on the phase compositions of the cemented carbides, but the mean grain size of the cemented carbides decreased as the addition fraction of SiC whisker increased. The fabricated WC-Ni cemented carbides presented the highest hardness when 0.75 wt% SiC whisker was added. However, the addition of SiC whisker was detrimental to the flexural strength of the cemented carbides because of the formation of inhomogeneous microstructure in the WC-Ni cemented carbides.

scholarly journals Effect of the Heating Rate on the Spark-Plasma-Sintering (SPS) of Transparent Y2O3 Ceramics: Microstructural Evolution, Mechanical and Optical Properties

Ceramics ◽  
2021 ◽  
Vol 4 (1) ◽  
pp. 56-69
Author(s):  
Lihong Liu ◽  
Koji Morita ◽  
Tohru S. Suzuki ◽  
Byung-Nam Kim
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Heating Rate ◽  
Spark Plasma Sintering ◽  
Near Infrared ◽  
Slow Heating ◽  
High Heating Rate ◽  
Plasma Sintering ◽  
High Heating ◽  
Spark Plasma

High strength transparent Y2O3 ceramics were fabricated from commercial powders using spark plasma sintering (SPS) technique by optimizing the heating rate. The heating rate significantly influenced the microstructures and the optical/mechanical properties of the Y2O3 ceramics. Grain growth was limited accordingly with increasing the heating rate. The ball milling process of the commercial Y2O3 powders is likely to further enhance the sinterability during the SPS processing. The dense Y2O3 ceramics, which were sintered by SPS with 100 °C/min, showed good transmittance range from visible to near infrared (IR). For a high heating rate of 100 °C/min, the in-line transmittance at a visible wavelength of 700 nm was 66%, whereas for a slow heating rate of 10 °C/min, it reduced to 46%. The hardness Hv tends to increase with increasing the heating rate and rigorously followed the Hall–Petch relationship; that is, it is enhanced with a reduction of the grain size. The toughness KIC, on the other hand, is less sensitive to both the heating rate and the grain size, and takes a similar value. This research highlighted that the high heating rate SPS processing can fabricate fully dense fine-grained Y2O3 ceramics with the excellent optical and mechanical properties.

Characterization of Y2O3, CeO2 and Y2O3+CeO2 Doped FGM Tetragonal ZrO2 Ceramics by Spark Plasma Sintering

2007 ◽  
Vol 333 ◽  
pp. 231-234 ◽  
Author(s):  
Shui Gen Huang ◽  
Omer Van der Biest ◽  
Jef Vleugels ◽  
Kim Vanmeensel ◽  
Lin Li
Keyword(s):  
Mechanical Properties ◽  
Spark Plasma Sintering ◽  
Tetragonal Zro2 ◽  
Zro2 Phase ◽  
Microstructure And Mechanical Properties ◽  
Plasma Sintering ◽  
Sample Edge ◽  
Spark Plasma ◽  
Ceo2 Reduction

In this study, 2 mol% Y2O3 (2Y), 1 mol% Y2O3+6 mol% CeO2 (1Y6Ce) and 12 mol% CeO2 (12Ce)-doped tetragonal ZrO2 ceramics were made by spark plasma sintering (SPS) for 2 min at 1450°C under a pressure of 60 MPa. The influence of stabilizers on microstructure, phase and mechanical properties of the ZrO2 ceramics was investigated. After sintering, the 2Y and 1Y6Ce were intact, containing full tetragonal ZrO2 phase on the polished cross-sectioned surface, whereas the 12Ce exhibited macro-cracks, corresponding to a large amount of monoclinic ZrO2 phase. Graded microstructure and mechanical properties were observed in the 1Y6Ce, showing a gradually decreased fracture toughness from sample edge towards centre, together with the slight decreased hardness. The 2Y had a uniform microstructure and mechanical properties. The formation of the graded structure and toughness profile was explained in terms of the gradual CeO2 reduction to Ce2O3 in the Y2O3+CeO2 doped ZrO2 ceramics.

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