Interactions between AlN and SiAlON Ceramics

2008 ◽  
Vol 403 ◽  
pp. 97-98
Author(s):  
A. Kalemtas ◽  
Nurcan Calis Acikbas ◽  
Ferhat Kara ◽  
Hasan Mandal ◽  
Kristoffer Krnel ◽  
...  

In the present study, interactions between AlN and SiAlON laminated couples were investigated after gas pressure (GPS) and spark plasma sintering (SPS) by scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDX) with the aim to produce laminated composites. In the laminated couples sintered by GPS, a significant reaction zone (~100-150 μm), containing a high aspect ratio of elongated polytypoid grains, was observed at the interface. However, in the case of laminated couples sintered by SPS, a considerably thin reaction region (~2-3 μm) was observed, elongated polytypoid grain formations were also detected.

2012 ◽  
Vol 727-728 ◽  
pp. 982-987
Author(s):  
E. de Carvalho ◽  
Marcelo Bertolete ◽  
Izabel Fernanda Machado ◽  
E.N.S. Muccillo

Polycrystalline CaCu3Ti4O12 ceramics were prepared by solid state reactions by spark plasma sintering (SPS) technique. In this study, the effects of the dwell temperature on structural, microstructural and dielectric properties of CaCu3Ti4O12 ceramics have been investigated. Powder mixtures were calcined at 900°C for 18 h before SPS consolidation. The dwell temperatures were 850, 900, 915 and 930°C. Sintered pellets were characterized by X-ray diffraction, scanning electron microscopy and impedance spectroscopy. X-ray diffraction patterns show evidences of a single-phase perovskite-type structure. The calculated lattice parameter is 7.40 Å. The hydrostatic density increases slightly with increasing dwell temperature. Scanning electron microscopy observations revealed a heterogeneous microstructure for all samples. The dielectric loss remains constant over a wide temperature range. The obtained permittivity is approximately 103 at 1 kHz. The increase of the dwell temperature is found to produce a brittle ceramic.


2004 ◽  
Vol 18 (01) ◽  
pp. 87-93 ◽  
Author(s):  
ZHIMIN WANG ◽  
YIDONG WU ◽  
YUANJIN HE

Crystals of MnSi 1.73 were prepared by Spark Plasma Sintering (SPS) technique, analyzed by X-ray diffraction (XRD), and invested by metalogragh and scanning electron microscopy (SEM). The growth processes of the samples were studied. It was found that the Mn–Si powders partly formed MnSi 1.73 crystals at 912–937 K under the mechanical pressure of 20 MPa in low vacuum (about 5.0 Pa), and fully formed MnSi 1.73 crystals after sintered at 1173 K for 15 minutes under 40 MPa.


2012 ◽  
Vol 500 ◽  
pp. 29-33
Author(s):  
Bao Rang Li ◽  
Xin Ming Xi ◽  
Yang Bai

The nano-TiO2powders with the average particle size of about 40nm were used as starting materials. The compacted powders were firstly performed in Spark-plasma-sintering (SPS) at a high temperature and then sintered in air for hours at a relatively low temperature. The obtained samples were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed an obvious reduction in grain size was achieved by taking advantage of modified two step sintering (MTSS). The value of the relative grain growth d/do for the samples prepared by MTSS was less than 3.


2011 ◽  
Vol 04 (04) ◽  
pp. 365-368 ◽  
Author(s):  
LENKA MALINOVÁ ◽  
VÁCLAVA BENEŠOVÁ ◽  
DANIELA LUBASOVÁ ◽  
LENKA MARTINOVÁ ◽  
JAN RODA ◽  
...  

The formation of novel high aspect ratio nanofibers from polyesteramides based on ε-caprolactam and ε-caprolactone is reported. Nanofibers were prepared by the electrospinning method from polymer solution. Scanning electron microscopy images of nanofiber layers revealed that the diameter of fibers depended on the nature of the solvent or the mixture of solvents used and especially on the composition of polyesteramides.


2020 ◽  
Vol 27 (11) ◽  
pp. 2050004
Author(s):  
HAMID GHANBARI ADIVI ◽  
IMAN EBRAHIMZADEH ◽  
MORTEZA HADI ◽  
MORTEZA TAYEBI

The pure iron and aluminum powders were milled with 3[Formula: see text]wt.% and 7[Formula: see text]wt.% of alumina nanoparticles in planetary ball mill in order to produce iron aluminide by mechanical alloying technique. The resulting powder mixture was sintered after the formation of iron aluminide by spark plasma sintering (SPS) method to achieve specimens with the highest densification. SPS technique was utilized on specimens under the condition of 40[Formula: see text]MPa pressure at 950∘C for 5[Formula: see text]min. The microstructures were analyzed after sintering using scanning electron microscopy and EDS analysis. The results indicated that the aluminide iron phase has been produced at high purity. The sintered specimens were treated under hardness and density tests, and it was characterized that the specimen included 3[Formula: see text]wt.% of alumina nanoparticles had the highest microhardness. Likewise, it was revealed that the unreinforced sample had a maximum relative density. The wear behavior of specimens was performed at 600∘C. The results of weight loss showed after 1000[Formula: see text]m of wear test, the weight loss of unreinforced specimen was reduced up to 0.21[Formula: see text]g while the specimen with 3[Formula: see text]wt.% of alumina nanoparticle indicated the lowest weight loss about 0.02[Formula: see text]g. The worn surfaces were evaluated by scanning electron microscopy which indicated that the main wear mechanism at high temperature included adhesive wear and delamination.


2013 ◽  
Vol 310 ◽  
pp. 80-84 ◽  
Author(s):  
Bei Ping Liu ◽  
Jian Chen ◽  
Fang Bo Liu ◽  
Shi Biao Zhou ◽  
Yuan Dao Chen ◽  
...  

Calcium carbonate whiskers were successfully prepared in the MgC12-Ca(OH)2-CO2 system by a intermittent bubbling method and characterized by X-ray diffraction and scanning electron microscopy. The results demonstrated that aragonite style calcium carbonate whiskers with well morphology, large aspect ratio and smooth surface can be obtained by controlling technical conditions such as reaction temperature, concentration of Ca(OH)2 and amount of additives and under the conditions of CO2 flow velocity of 3.4ml/min/gCa(OH)2, flow of CO2 to air ratio of 1:4, stirring speed of 240 r/min.


2012 ◽  
Vol 512-515 ◽  
pp. 932-935
Author(s):  
Ying Peng ◽  
Zhi Jian Peng ◽  
Xiao Yong Ren ◽  
Hui Yong Rong ◽  
Cheng Biao Wang ◽  
...  

TiCN-based cermets with different amounts of SiC nano-whiskers were prepared by spark plasma sintering. The microstructure and mechanical properties of the as-prepared cermets were investigated. X-ray diffraction revealed that there were no SiC peaks detected, turning out some peaks of new carbide and silicate hard phases. Scanning electron microscopy indicated that there were more and more pores in the cermets with increasing amount of SiC whisker added, and the fracture mechanism of the cermets was mainly inter-granular fracture. With increasing addition amount of nano-SiC whisker, the hardness and flexural strength of the cermets increased first and decreased then, presenting the highest hardness (2170 HV) and flexural strength (750 MPa), respectively, when the addition content of nano-whiskers is 2.5 wt%.


2016 ◽  
Vol 685 ◽  
pp. 724-728
Author(s):  
Sergey P. Zhuravkov ◽  
Alexsey Pobol ◽  
Galina L. Lobanova ◽  
George Goranskyi ◽  
Filipp Saprikin

Powders of WC-6Co hard alloy were produced using spark erosion in distilled water. The properties of powders, such as specific surface area, morphology, structure and size distribution, were studied. Investigation of the powder properties was made using the methods of scanning electron microscopy, X-ray phase analysis and disk centrifuge.


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