Preparation and Magnetic Properties of Dense NiCuZn Ferrite by Spark Plasma Sintering

2008 ◽  
Vol 368-372 ◽  
pp. 601-603
Author(s):  
Xi Wei Qi ◽  
Ji Zhou ◽  
Zhen Xing Yue ◽  
Ming Ya Li ◽  
Xiu Mei Han
Keyword(s):  
Spark Plasma Sintering ◽  
Annealing Temperature ◽  
Annealing Treatment ◽  
Impurity Phase ◽  
Uniaxial Pressure ◽  
Plasma Sintering ◽  
Average Grain Size ◽  
Conventional Sintering ◽  
Spark Plasma ◽  
Nicuzn Ferrite

Dense NiCuZn ferrites consisting of fine grains were prepared by spark plasma sintering (SPS) at 750°C for 3 min under a uniaxial pressure of 15 MPa. The powders were densified to >95% of theoretical density by the SPS process, and the average grain size of the prepared NiCuZn ferrite was < 1 /m. The saturation magnetization of prepared specimens (without further annealing treatment) was approximate 50.54 emu/g, which was slightly smaller than that of 52.21 emu/g for specimens prepared by conventional sintering at 980°C for 4 h. Phase identifications indicated that prepared NiCuZn ferrite existed impurity phase (Cu2O), and Cu2O would gradually transform to CuO when annealing temperature increased.

scholarly journals Density, Microstructure, Strength and Fractography of Spark Plasma and Conventionally Sintered Mn Steels

2017 ◽  
Vol 17 (2) ◽  
pp. 93-103
Author(s):  
M. Tenerowicz-Zaba ◽  
M. Kupkova ◽  
M. Kabatova ◽  
E. Dudrova ◽  
M. Dzupon ◽  
...  
Keyword(s):  
Heating Rate ◽  
Spark Plasma Sintering ◽  
Failure Mechanisms ◽  
Uniaxial Pressure ◽  
Preliminary Results ◽  
Heating And Cooling ◽  
Plasma Sintering ◽  
Conventional Sintering ◽  
Spark Plasma ◽  
Sintered Materials

Abstract The aim of the study was to investigate Spark Plasma Sintering (SPS) of 1-3%Mn steels and compare the resultant microstructures, strengths and failure mechanisms with those of conventionally sintered materials. SPS was performed in a vacuum of 5 Pa at 1000°C for 15min under a uniaxial pressure of 20 MPa. The heating rate of 100°C/min was applied. For conventional processing, mixtures of powders were prepared in a Turbula mixer for 30 minutes. Samples were single pressed at 660 MPa, according to PN-EN ISO 2740 standard. Sintering of compacts was carried out in a laboratory tube furnace at 1120°C and 1250°C for 60 minutes in a mixture of 95%N2-5%H2. Heating and cooling rates were 75C°/min and 60°C/min, respectively. The density of SPS samples was higher (up to 7.37 g/cm3) than those after conventional sintering (up to 6.7 g/cm3). Yield strengths of SPS samples were in the range 920-1220 MPa, compared to the maximum of 602 MPa for conventionally sintered Fe-3%Mn-0.8%C. Transverse rupture strengths were the same for this alloy, 1234 MPa, but reached 1473 MPa for SPS 2Mn variant. Interfaces in SPS samples were significantly less contaminated with oxides, which is the result of a more favorable microclimate and pressure acting during SPS. These preliminary results indicate that further research on the SPS of Mn steels is warranted.

The Synthesis of CaCu3Ti4O12 High Dielectric Ceramics by a Spark Plasma Sintering Method

2013 ◽  
Vol 538 ◽  
pp. 250-253 ◽  
Author(s):  
Xue Feng Ruan ◽  
Zhi Yang ◽  
Yue Zhang ◽  
Jing Shi ◽  
Rui Xiong
Keyword(s):  
Dielectric Properties ◽  
Spark Plasma Sintering ◽  
Photoelectron Spectroscopy ◽  
Annealing Temperature ◽  
Annealing Treatment ◽  
Dielectric Constants ◽  
Characterization Methods ◽  
X Ray ◽  
Plasma Sintering ◽  
Spark Plasma

CaCu3Ti4O12 (CCTO) ceramics were synthesized by a spark plasma sintering technique, and then were annealed in air at different temperatures. The characterization methods including X-ray diffraction, X-ray photoelectron spectroscopy indicated that the composition distribution, the valance of the Ti ions of the CCTO ceramics have great dependence on the annealing temperature, which result in that the dielectric properties of the CCTO ceramics have great dependence on the annealing temperature. The annealing at 500 and 700 °C can enhance the dielectric constants greatly, and the dielectric loss at high frequence (1 MHz) reduces with the increase of the annealing temperature. These annealing-dependent dielectric properties are ascribed to the oxygen vacancies and the holes formed in the sintering and annealing treatment.

scholarly journals Processing of MMC through conventional sintering and spark plasma sintering process: A review

2020 ◽  
Vol 988 ◽  
pp. 012092
Author(s):  
B Stalin ◽  
M Ravichandran ◽  
M Balasubramanian ◽  
C Anand Chairman ◽  
D Pritima ◽  
...  
Keyword(s):  
Spark Plasma Sintering ◽  
Sintering Process ◽  
Plasma Sintering ◽  
Conventional Sintering ◽  
Spark Plasma

scholarly journals Porosity and Microstructure Iron-Based Graded Materials Sintered by Spark Plasma Sintering and the Conventional Method

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 264
Author(s):  
Krzysztof Zarębski ◽  
Piotr Putyra ◽  
Dariusz Mierzwiński
Keyword(s):  
Spark Plasma Sintering ◽  
Graded Materials ◽  
Gradient Zone ◽  
Die Filling ◽  
Plasma Sintering ◽  
Gradient Microstructure ◽  
Conventional Sintering ◽  
Spark Plasma ◽  
Local Range ◽  
Sintering Method

Using PNC-60 powder with the addition of graphite, cylindrical products characterized by different compositions of core and outer layers were made. Some compacts were sintered via the conventional process, while others were subjected to the spark plasma sintering method (SPS) at different times and temperatures. The gradient microstructure was obtained in the transition zone by mixing powders during die filling, followed by pressing and diffusion during sintering. The effect of sintering parameters on the nature of the gradient zone and the morphology of the pores was shown. After conventional sintering, the gradient zone was wider than it was after SPS. Via SPS, the short sintering time confined the diffusion to a local range, making its influence on the gradient structure negligible. Differences in the microstructure were confirmed by functional description.

Preparation of Fine-grained BaTiO3 Ceramics by Spark Plasma Sintering

2002 ◽  
Vol 17 (3) ◽  
pp. 575-581 ◽  
Author(s):  
Tomonari Takeuchi ◽  
Claudio Capiglia ◽  
Nalini Balakrishnan ◽  
Yasuo Takeda ◽  
Hiroyuki Kageyama
Keyword(s):  
Grain Size ◽  
Spark Plasma Sintering ◽  
Fine Powder ◽  
Fine Grained ◽  
Plasma Sintering ◽  
Average Grain Size ◽  
Ferroelectric Domains ◽  
Spark Plasma ◽  
Ray Density ◽  
Permittivity Measurements

Dense BaTiO3 ceramics consisting of fine grains were prepared using fine powder (average grain size of 0.06 μm; BT006) as a starting material and the spark plasma sintering (SPS) method. The powder was densified to >95% of theoretical x-ray density by the SPS process, and the average grain size of the resulting ceramics was <0.5 μm; the particle size of the initial powder significantly affects the grain size of the resulting SPS pellets. Fixed-frequency (100 kHz), room-temperature permittivity measurements of the BT006-SPS ceramics showed relatively low values (3000–3500) compared with those (typically 5000) for SPS ceramics consisting of larger grains (approximately 1 μm). Lower permittivity was attributed to poor development of ferroelectric domains in the ceramics, which originated from incomplete development of the tetragonal structure as well as the presence of a local orthorhombic structure.

Synthesis and Thermoelectric Properties of Ca2Co2O5 Ceramics

2010 ◽  
Vol 434-435 ◽  
pp. 400-403 ◽  
Author(s):  
Shu Jin Zhao ◽  
Guo Jing Li ◽  
Yang Zhang ◽  
Ao Mei ◽  
Jin Le Lan ◽  
...  
Keyword(s):  
Relative Density ◽  
Spark Plasma Sintering ◽  
Thermoelectric Properties ◽  
Coprecipitation Method ◽  
Plasma Sintering ◽  
Conventional Sintering ◽  
Spark Plasma

The precursor of Ca2Co2O5 was prepared by coprecipitation method. The bulk Ca2Co2O5 samples were prepared by conventional sintering and Spark Plasma Sintering (SPS), respectively. The relative density of bulk Ca2Co2O5 ceramic, which was prepared by conventional sintering is about 75%; while the samples prepared by SPS has a density of 98%. The thermoelectric properties were enhanced by SPS, compared with samples prepared with conventional sintering. The maximum powerfactor of the conventional sintering and SPS samples are 2.70×10-4W∙m-1∙K-2 and 3.85×10-4 W∙m-1∙K-2, respectively.

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