scholarly journals Influence of the Uniaxial Hot-Pressing Sintering Condition on Bi4Ge3O12 Ceramic Scintillators

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Ivus L. O. Matos ◽  
Adriano B. Andrade ◽  
Zélia S. Macedo ◽  
Mário E. G. Valerio

The production of high-density bismuth germanate (Bi3Ge4O12) ceramic scintillators by uniaxial hot pressing was investigated as a function of different applied pressure conditions. The X-ray diffraction showed that the sintering process was able to eliminate the undesirable secondary phase present in the nonsintered samples. The height changes from samples with higher applied pressure rate and applied pressure duration lead to a better relative density value, >95% for samples sintered under a pressure of 0.14 and 0.18 MPa. The radioluminescence results showed that all samples have the characteristic emission spectra of Bi3Ge4O12 and that the hot-pressed samples have higher radioluminescence emission efficiency.

2017 ◽  
Vol 726 ◽  
pp. 316-320 ◽  
Author(s):  
Jie Gao ◽  
You Jun Lu ◽  
Jun Feng Hou ◽  
Zhen Xia Yuan ◽  
Wen Luo ◽  
...  

The Mo powder and Nb powder was used as raw material, the Mo-10Nb alloy target was prepared by different sintering condition (non-pressure sintering and hot pressing sintering). The density, phase composition, microstructure and elemental distribution of Mo-10Nb alloy targets were determined by X-ray diffraction and scanning electron microscopy. The results showed that prepared by hot pressing Mo-10Nb alloy target density of 9.618 g/cm3, grain size 20 ~ 30μm, Mo and Nb element distribution.


2013 ◽  
Vol 745-746 ◽  
pp. 700-705
Author(s):  
Huang Liu ◽  
Guo Qiang Luo ◽  
Pin Gan Chen ◽  
Qiang Shen ◽  
Lian Meng Zhang

SiC/Cu composites exhibit low density, low coefficient of thermal expansion and excellent mechanical properties. In this study, Zn of 2 wt. % was added as the sintering activator, and the high volume faction (60%) SiC/Cu composites was fabricated by hot pressing sintering technology. The phase composition and morphology of as-prepare samples were characterized by X-ray diffraction (XRD) system and scanning electron microscopy (SEM) equipped with an energy-dispersive spectroscopy (EDS) system. The as-prepared SiC/Cu composites were dense and uniform as well as void free. The results show that SiC/Cu composites can reach excellent mechanical properties of SiC/Cu composites. With the increase of sintering temperature, Vickers hardness and the bending strength of the samples increased obviously and the as-prepared SiC/Cu composites achieved a maximum Vickers hardness and bending strength respectively of 195MPa and 140MPa.


2013 ◽  
Vol 483 ◽  
pp. 65-70 ◽  
Author(s):  
Jun Zhou ◽  
Fu Qing Zhang ◽  
Li Hong Xia

The chalcopyrite-type of CuIn0.7Ga0.3Se2 nanoparticle was successfully prepared by mechanical alloying method (MA). The phase of the obtained powder was analyzed by x-ray diffraction (XRD), and its microstructure was analyzed by scanning electron microscope (SEM) and transmission election microscope (TEM). Subsequently, the sintering process of CIGS quarternary target was investigated. The result suggests that only CuIn0.7Ga0.3Se2 phase exist in the powder with the rotation speed of 350 r/min and 2 hours mixing time by planetary ball milling. The particles were seriously agglomerated and the size of agglomerates was about 100 nm. Finally the as-made CIGS nanoparticles were used to fabricate CIGS target through both pressureless sintering and hot pressing methods. The hot pressing was fairly effective to increase the density of CIGS target. This fabricated target can be used for magnetron-sputtering deposition of CIGS absorbers.


2021 ◽  
Vol 8 ◽  
Author(s):  
Rakhi Madhuri ◽  
Santha Narayana Iyer ◽  
Subodh Ganesanpotti

Cold sintering process (CSP) was successfully employed to fabricate (1 − x) NaCa2Mg2V3O12-xNaCl [abbreviated as (1 − x) NCMVO-xNaCl] microwave dielectric ceramics. (1 − x)NCMVO-xNaCl ceramics prepared at 200°C and at a pressure of 450 MPa had a high relative density of 80–94%. X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), and Raman spectroscopy showed that both NCMVO and NaCl phases co-exist in all composite ceramics without forming any secondary phase. Further, dependence of microstructure and dielectric properties on cold sintering temperature and duration were investigated in detail and their optimized values to obtain maximum density of ceramic composites were 200°C and 50 min, respectively. (1 − x)NCMVO-xNaCl (x = 0.4–0.7) composites have relative permittivity (εr) in the range of 6.9–7.4, and a reasonably high microwave quality factor (Q × f) of 5,000 to 13,830 GHz.


2018 ◽  
Vol 24 (4) ◽  
pp. 273 ◽  
Author(s):  
Khanh Quoc Dang ◽  
Quang Anh Hoang ◽  
Hiep Van Tran ◽  
Minh Cong Nguyen ◽  
Hao Van Pham ◽  
...  

In the present work, FeMn13-40 wt.% TiC composite was fabricated by Pulsed Electric Current Sintering (PECS) process at different temperatures between 990 and 1020<sup>o</sup>C under a pressure of 60 MPa with a holding time of 5 min in the vacuum. Phases identification was done using the X-ray diffraction. The relative density, microstructure and hardness of the samples were characterized. The results showed that the relative density of FeMn13-TiC composite increased with the increase of sintering temperature. The highest relative density (96.19%) and the hardness (70.54 HRC) of the sample were achieved by PECS process, namely sintering at the temperature of 1020<sup>o</sup>C under the applied pressure of 60 MPa for 5 min.


2016 ◽  
Vol 881 ◽  
pp. 307-312
Author(s):  
Luis Antonio C. Ybarra ◽  
Afonso Chimanski ◽  
Sergio Gama ◽  
Ricardo A.G. da Silva ◽  
Izabel Fernanda Machado ◽  
...  

Tungsten carbide (WC) based composites are usually produced with cobalt, but this binder has the inconvenience of shortage, unstable price and potential carcinogenicity. The objective of this study was to develop WC composite with intermetallic Fe3Al matrix. Powders of WC, iron and aluminum, with composition WC-10 wt% Fe3Al, and 0.5 wt% zinc stearate were milled in a vibration mill for 6 h and sintered in a SPS (spark plasma sintering) furnace at 1150 °C for 8 min under pressure of 30 MPa. Measured density and microstructure analysis showed that the composite had significant densification during the (low-temperature, short time) sintering, and X-ray diffraction analysis showed the formation of intermetallic Fe3Al. Analysis by Vickers indentation resulted in hardness of 11.2 GPa and fracture toughness of 24.6 MPa.m1/2, showing the feasibility of producing dense WC-Fe3Al composite with high mechanical properties using the SPS technique.


2015 ◽  
Vol 1 (1) ◽  
Author(s):  
M. Araújo ◽  
M. Miola ◽  
A. Venturello ◽  
G. Baldi ◽  
J. Perez ◽  
...  

AbstractIn this work, sintered pellets of a silica-based bioactive glass were dip-coated with a biocompatible natural-derived polymer in order to investigate the influence of the organic coating on the glass bioactivity. After the sintering process optimization, uncoated and coated pellets have been characterized by means of scanning electron microscopy with energy dispersive spectroscopy (SEM, EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and pH measurements, after the immersion in a simulated body fluid (SBF). An increased apatite forming ability and a better control of the pH during soaking of the samples in SBF were observed in the presence of the biopolymer. This result opens a new insight on the simple fabrication of highly bioactive hybrid inorganic-organic materials for medical applications.


2011 ◽  
Vol 268-270 ◽  
pp. 356-359 ◽  
Author(s):  
Wen Song Lin ◽  
C. H. Wen ◽  
Liang He

Mn, Fe doped ZnO powders (Zn0.95-xMnxFe0.05O2, x≤0.05) were synthesized by an ameliorated sol-gel method, using Zn(CH3COO)2, Mn(CH3COO)2and FeCl2as the raw materials, with the addition of vitamin C as a kind of chemical reducer. The resulting powder was subsequently compacted under pressure of 10 MPa at the temperature of 873K in vacuum. The crystal structure and magnetic properties of Zn0.95-xMnxFe0.05O2powder and bulk samples have been investigated by X-ray diffraction (XRD) and vibrating sample magnetometer (VSM). X-ray photoelectron spectroscopy (XPS) was used to study chemical valence of manganese, iron and zinc in the samples. The x-ray diffraction (XRD) results showed that Zn0.95-xMnxFe0.05O (x≤0.05) samples were single phase with the ZnO-like wurtzite structure. No secondary phase was found in the XRD spectrum. X-ray photoelectron spectroscopy (XPS) showed that Fe and Mn existed in Zn0.95-xMnxFe0.05O2samples in Fe2+and Mn2+states. The results of VSM experiment proved the room temperature ferromagnetic properties (RTFP) of Mn, Fe co-doped ZnO samples.


2021 ◽  
Vol 54 (1) ◽  
pp. 371-375
Author(s):  
Paul Monceyron Røren ◽  
Kristoffer W. B. Hunvik ◽  
Vegard Josvanger ◽  
Ole Tore Buseth ◽  
Jon Otto Fossum

A sample cell for powder X-ray diffraction studies with in situ applied pressure and control of temperature is demonstrated. The cell is based on a previously reported design and consists of a glass or quartz capillary glued into a Swagelok weld gland; this configuration can hold up to 100 bar (1 bar = 100 kPa). The cell is placed in contact with a copper plate for control of temperature between −30 and 200°C. This is achieved by Peltier elements, heat cartridges and a refrigerated circulating bath. This work mainly focuses on the temperature control system. Commissioning tests were performed in a custom-made small/wide-angle X-ray diffractometer at the Norwegian University of Science and Technology. The system is easily portable to synchrotron facilities.


2006 ◽  
Vol 530-531 ◽  
pp. 364-368
Author(s):  
G. de Vasconcelos ◽  
R. Cesar Maia ◽  
Carlos Alberto Alves Cairo ◽  
R. Riva ◽  
N.A.S. Rodrigues ◽  
...  

In this study, the results of the feasibility of sintering green compacts of metallic powder of MoSi2 by a CO2 laser beam as the heating source has been investigated. The main advantage of this technique is to promote a dense material in a reduced time when compared to the conventional sintering process. In order to sintering the MoSi2 powder, green compacts of 6mm of diameter and 1.6mm thickness were produced in a steel die in a uniaxial press at 100MPa and after, isostatic pressed at 350MPa. The micrograph of the samples exposed to the laser radiation performed by scanning electron microcopy (SEM) reveal the efficiency of the sintering process and the X-ray diffraction of the powders confirmed the presence of single phase after and before laser processing. The average microhardness of these compacts reached near to 700 Hv0.2 in the cross section to the laser irradiation, indicating the all sintering of the green compact.


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