scholarly journals Формирование мелкодисперсного термоэлектрика Si-=SUB=-1-x-=/SUB=-Ge-=SUB=-x-=/SUB=- при электроимпульсном плазменном спекании

2021 ◽  
Vol 91 (12) ◽  
pp. 1975
Author(s):  
М.В. Дорохин ◽  
М.С. Болдин ◽  
Е.А. Ускова ◽  
А.В. Боряков ◽  
П.Б. Демина ◽  
...  
Keyword(s):  
Diffusion Processes ◽  
Particle Sizes ◽  
Initial Powder ◽  
Sintering Process ◽  
Plasma Sintering ◽  
Powder Particles ◽  
First Time ◽  
Kinetics Of ◽  
Pulse Plasma Sintering ◽  
Comprehensive Study

The kinetics of diffusion processes occurring d0uring the formation of polycrystalline Si1-xGex nanostructures (x=0.20, 0.35) by electro-pulse plasma sintering in the temperature range 20-1200°C was studied for the first time. A mechanism for the formation of a solid solution of SiGe is proposed as a result of a comprehensive study of the microstructure and phase composition of samples with particle sizes from 150 nm to 100 μm, together with the analysis of experimental sintering maps. It is based on the phenomenon of mutual diffusion of Si and Ge atoms that occurs during the entire sintering process. For the selected sintering modes, the grain size of the formed SiGe corresponds to the size of the initial powder particles.

Pulse Plasma Sintering of Nano-Crystalline Cu Powder

2006 ◽  
Vol 114 ◽  
pp. 239-244 ◽  
Author(s):  
Andrzej Michalski ◽  
Marcin Rosiński ◽  
D. Siemiaszko ◽  
Jakub Jaroszewicz ◽  
Krzysztof Jan Kurzydlowski
Keyword(s):  
Relative Density ◽  
Crystallite Size ◽  
Average Crystallite Size ◽  
Pulse Plasma ◽  
Sintering Process ◽  
Nanocrystalline Copper ◽  
Nano Crystalline ◽  
Plasma Sintering ◽  
Copper Powders ◽  
Pulse Plasma Sintering

Nanocrystalline copper powders, produced by the reduction of the CuO with hydrogen, were consolidated using the pulse plasma sintering (PPS) method. The sintering process was carried out at temperatures between 500 and 900 oC under a load of 60 MPa for 5 min. The average crystallite size of the sintered component obtained at 500 oC was about 80nm and at 900 oC 1880 nm. The components produced at 500 oC had a relative density of 90 %, and those sintered at 900 oC 92 %; their hardness was 215 and 140 HV0.1, respectively.

Nanometric powders and sintered ceramics studied by atomic force microscopy

1998 ◽  
Vol 13 (1) ◽  
pp. 223-227 ◽  
Author(s):  
A. Dias ◽  
R. L. Moreira ◽  
N. D. S. Mohallem ◽  
J. M. C. Vilela ◽  
M. S. Andrade
Keyword(s):  
Atomic Force Microscopy ◽  
Ceramic Powder ◽  
Direct Analysis ◽  
Particle Sizes ◽  
Preparation Technique ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Powder Particles

Atomic force microscopy, as well as the Brunauer, Emmett, and Teller technique and x-ray diffraction, was used to analyze ultrafine NiZn ferrite powders hydrothermally synthesized at 200 °C, for 5 h. The particle sizes, measured through AFM images acquired from the surface of pressed powders, were 52 ± 6 nm, which were higher than those obtained by the other techniques. The particles were monodispersed in size and approximately spherical, meeting the requirements for the production of high density sintered components. The observations performed on ceramic bodies sintered at different conditions (1100–1400 °C, 5 to 240 min) showed necks characteristic of the early stages of sintering (1100 °C) and the expected pore curvature evolution (1400 °C) with sintering time in the final stage of the sintering process. Using a straightforward sample preparation technique, AFM proved to be a powerful tool for direct analysis of ceramic powder particles on the nanometric scale and sintered ceramics at different sintering stages.

scholarly journals Effect of Milling Conditions on the Microstructural Design in Aluminum Based Alloy Fabricated by SPS

Metals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1164
Author(s):  
Anton Smirnov ◽  
Ekaterina Kuznetsova ◽  
Yuri Pristinskiy ◽  
Pavel Podrabinnik ◽  
Alexander Mironov ◽  
...  
Keyword(s):  
Milling Time ◽  
Milling Process ◽  
Mechanically Alloyed ◽  
Microstructural Characteristics ◽  
X Ray ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Powder Particles ◽  
Microstructural Design ◽  
First Time

In this work, aluminum-based alloys were mechanically alloyed by various doping elements followed by spark plasma sintering. Three different mixing methods were studied. First, all elemental powders were mixed for 24 h. In the second and the third method, powders were divided into three groups, and each group was milled separately for different times. Then the obtained mixtures were grouped together and again milled for 12 and 24 h, for the M2 and M3 mixtures, respectively. The influence of milling parameters on the microstructural features of sintered samples was determined using a scanning electron microscope (SEM) equipped with an energy-dispersive X-ray spectroscopy system. The correlation observed between the milling time and microstructural evolution of the powder particles during the milling process was to determine the optimal process parameters. For the first time, the present research has demonstrated the effectiveness of the milling process for the preparation of tailored mixtures of metallic powders, enabling microstructural characteristics that could be favorable for the formation of secondary structures on the tribosurfaces.

WC/Ti Composite Material Enriched with CBN Particles Produced by Pulse Plasma Sintering (PPS)

2011 ◽  
Vol 484 ◽  
pp. 130-134 ◽  
Author(s):  
Marcin Rosiński ◽  
Andrzej Michalski ◽  
Magdalena Płocińska ◽  
Jerzy Szawłowski
Keyword(s):  
Sintered Material ◽  
Cubic Boron Nitride ◽  
Pulse Plasma ◽  
Sintering Process ◽  
Surrounding Matrix ◽  
Plasma Sintering ◽  
The Matrix ◽  
Binding Forces ◽  
Straight Lines ◽  
Pulse Plasma Sintering

Tungsten carbide (WC) and WCCo powders added with 30 vol.% cubic boron nitride (cBN) and 5 and 12 wt% of Ti were sintered by the pulse plasma sintering (PPS) technique. The sintering process was conducted under a load of 75 MPa at a pressure of 5.10- 5 mbar and a temperature of 1100-1500°C for 5min. The phase composition, density, hardness and microstructure of the sintered material thus obtained were examined. In the cBN-WCTi5wt% composite with an addition of 6wt% Co, the cBN particles are well bound with the matrix. The transcrystalline fractures of the cBN particles also indicate that the binding forces between these particles and the WCCoTi matrix exceed the matrix cohesion. The interfaces between the cBN grains and the surrounding matrix are almost straight lines, and no reactions between the cBN grains and the matrix were revealed in SEM observations.

scholarly journals Densification Kinetics of Multi-Doped Zirconia Ceramic Body with Organic Coating Powders

2018 ◽  
Author(s):  
Y.G. Hoo ◽  
Yusheng Shi ◽  
Wenzhong Lu
Keyword(s):  
Solid Oxide Fuel Cells ◽  
Ceramic Body ◽  
Equivalent Strain ◽  
Organic Coating ◽  
Zirconia Ceramic ◽  
Sintering Process ◽  
Zirconia Ceramics ◽  
Initial Stage ◽  
First Time ◽  
Kinetics Of

Abstract: This work for the first time investigated the densification of multi-doping zirconia ceramic body with organic coating powders for solid electrolyte of solid oxide fuel cells via online imaging technology. The densification results show the initial stage plays a key role in the sintering. It can be found the covered organic PVA (polyvinyl acetate) supplies a potential kinetics to the initial densification during sintering. As a result, a kinetic function of densification in the initial stage was suggested. Furthermore, a novel sintering model with six sub-stages is developed for polycrystalline zirconia ceramics. The findings would be a valuable reference for predicting final temperature of sintering, the equivalent strain during the sintering process, as well as optimizing the densification behavior.

scholarly journals Mechanical Properties of WC-Si3N4 Composites With Ultrafine Porous Boron Nitride Nanofiber Additive

2021 ◽  
Vol 8 ◽  
Author(s):  
Ting Cao ◽  
Xiaoqiang Li ◽  
Jingmao Li ◽  
Yang Huang ◽  
Shengguan Qu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Liquid Phase ◽  
Boron Nitride ◽  
Probable Mechanism ◽  
Sintering Process ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Catastrophic Fracture ◽  
First Time

WC-10 wt.% Si3N4 composites toughened with ultrafine porous boron nitride nanofiber (0, 0.01, 0.05, 0.1, and 0.15 wt.%) were prepared for the first time by spark plasma sintering. Compared with the WC-Si3N4 composite sintered in the same condition, the obtained WC-10 wt.% Si3N4 composites with ultrafine porous boron nitride were found to possess better hardness and fracture toughness. In addition, the Si3N4 phase in the UPBNNF toughened composites did not exhibit traditional catastrophic fracture as indicated in most investigations. In this study, the phenomena are discussed, and a probable mechanism is elucidated. It is deduced that the approach could be extended to materials with a feature of internal liquid phase during the sintering process and could improve hardness and fracture toughness.

Fabrication and Mechanical Properties of ultra fine WC-6wt.%Co by Spark Plasma Sintering Process

2011 ◽  
Vol 49 (01) ◽  
pp. 40-45 ◽  
Author(s):  
Hyun-Kuk Park ◽  
Seung-Min Lee ◽  
Hee-Jun Youn ◽  
Ki-Sang Bang ◽  
Ik-Hyun Oh
Keyword(s):  
Mechanical Properties ◽  
Spark Plasma Sintering ◽  
Sintering Process ◽  
Plasma Sintering ◽  
Spark Plasma

Zeolites Fit For A Crown: Probing Host-Guest Interactions with Thermogravimetric Methods

2018 ◽  
Author(s):  
Asel Sartbaeva ◽  
Paul R. Raithby ◽  
Remi Castaing ◽  
Antony Nearchou
Keyword(s):  
Mass Spectrometry ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Petrochemical Industry ◽  
Rational Use ◽  
New Methodologies ◽  
First Time ◽  
Kinetics Of

Through a combination of thermogravimetry, mass spectrometry and differential thermal analysis, we demonstrate for the first time that all four zeolites show experimental differences in their host-guest interactions with 18C6. In addition, we have estimated the kinetics of 18C6 decomposition, which is a technique that has not been applied to zeolites previously. Using these findings as a toolkit, a more rational use of OSDAs can be utilised to prepare designer zeolites. Furthermore, the new methodologies presented herein can be applied to current zeolites, such as MFI-type zeolites used in the petrochemical industry.

scholarly journals Oxidation behavior of non-stoichiometric (Zr,Hf,Ti)Cx carbide solid solution powders in air

2021 ◽  
Author(s):  
Huilin Lun ◽  
Yi Zeng ◽  
Xiang Xiong ◽  
Ziming Ye ◽  
Zhongwei Zhang ◽  
...  
Keyword(s):  
Solid Solution ◽  
Oxidation Resistance ◽  
Oxidation Behavior ◽  
Group Iv ◽  
Hypersonic Vehicles ◽  
Metal Carbides ◽  
Initial Oxidation ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Kinetics Of

AbstractMulti-component solid solutions with non-stoichiometric compositions are characteristics of ultra-high temperature carbides as promising materials for hypersonic vehicles. However, for group IV transition-metal carbides, the oxidation behavior of multi-component non-stoichiometric (Zr,Hf,Ti)Cx carbide solid solution has not been clarified yet. The present work fabricated four kinds of (Zr,Hf,Ti)Cx carbide solid solution powders by free-pressureless spark plasma sintering to investigate the oxidation behavior of (Zr,Hf,Ti)Cx in air. The effects of metallic atom composition on oxidation resistance were examined. The results indicate that the oxidation kinetics of (Zr,Hf,Ti)Cx are composition dependent. A high Hf content in (Zr,Hf,Ti)Cx was beneficial to form an amorphous Zr-Hf-Ti-C-O oxycarbide layer as an oxygen barrier to enhance the initial oxidation resistance. Meanwhile, an equiatomic ratio of metallic atoms reduced the growth rate of (Zr,Hf,Ti)O2 oxide, increasing its phase stability at high temperatures, which improved the oxidation activation energy of (Zr, Hf, Ti)Cx.

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