Effect of two-step heating on transparency of MgAl2O4 ceramics fabricated by pulsed electric current sintering process

2021 ◽  
Vol 95 ◽  
pp. 11-17
Author(s):  
Khanh Dang Quoc ◽  
◽  
Yen Nguyen Ngoc ◽  
Tu Dao Anh ◽  
Thang Le Hong ◽  
...  
Keyword(s):  
Grain Size ◽  
Electric Current ◽  
Ceramic Powder ◽  
Second Step ◽  
Transparent Ceramics ◽  
Sintering Process ◽  
Ceramic Samples ◽  
Pulsed Electric Current ◽  
Step Heating ◽  
One Step

In this work, MgAl2O4 transparent ceramics was fabricated from combustion-synthesized nanopowders by pulsed electric current sintering (PECS) combined with two-step sintering. Ceramic powder was densitified using two-step heating, namely the first-step temperature was 1100 oC with holding time of 60 min and the second-step temperatures in range from 1300 oC to 1450 oC with 20 min duration. The results showed that the transparent ceramic samples sintered at 1100 oC/60 min – 1400 oC/20 min had grain size of 177 ± 8 nm, relative density about 99 %, transmittance up to 80 %, and Vickers hardness of 18 GPa. These values were higher than that of samples obtained by one-step sintering at 1400 oC.

scholarly journals Preparation of Transparent MgAl2O4 Spinel by Pulsed Electric Current Sintering Using Two-step Heating Method

2021 ◽  
Vol 27 (4) ◽  
pp. 203-206
Author(s):  
Yen Ngoc Nguyen ◽  
Hai Minh Le ◽  
Tu Anh Dao ◽  
Hung Ngoc Tran ◽  
Tue Ngoc Nguyen ◽  
...  
Keyword(s):  
Electric Current ◽  
Applied Pressure ◽  
Solution Combustion Synthesis ◽  
Second Step ◽  
Infrared Range ◽  
Transparent Ceramics ◽  
Sintering Process ◽  
Solution Combustion ◽  
Pulsed Electric Current ◽  
Step Heating

Transparent MgAl2O4 ceramics were fabricated by pulsed electric current sintering (PECS) employing two-step sintering mode. First, nanoscale MgAl2O4 powders were produced by solution combustion synthesis from hydrated nitrate compounds and urea. Subsequently, the synthesized powders were sintered by PECS with a heating rate of 100oC/min under an applied pressure of 100 MPa. The sintering process was conducted according to two-step heating profile. At the first step, the temperature increased to 1050, 1100, and 1150oC, followed by a dwell time of 60 min. The second-step sintering was carried out at 1300, 1350, and 1400oC for 20 min. The transparent ceramics sintered at 1050oC/ 60 min – 1400oC/ 20 min exhibited transmittance over 80% in infrared range. In addition, transparent samples presented a Vickers hardness up to 30 GPa for sintering mode of 1150oC/ 60 min – 1400oC/ 20 min.

223 Solid Bonding of Aluminum alloy amd Mild Steel by Pulsed Electric-Current Sintering Process

2001 ◽  
Vol 2001.9 (0) ◽  
pp. 301-302
Author(s):  
Shogo TOMIDA ◽  
Takekazu NAGAE ◽  
Kazuhiro NAKATA ◽  
Shigeoki SAJI ◽  
Susumu KATO
Keyword(s):  
Aluminum Alloy ◽  
Mild Steel ◽  
Electric Current ◽  
Sintering Process ◽  
Pulsed Electric Current

Altering the Microstructure of Pearlitic Steel Using Pulsed Electric Current

2016 ◽  
Vol 1139 ◽  
pp. 3-6 ◽  
Author(s):  
Bernadette Elliott-Bowman ◽  
Alexander C. Cook ◽  
Peter Brown ◽  
David Dye ◽  
Rong Shan Qin
Keyword(s):  
Grain Size ◽  
Electric Current ◽  
Pulse Duration ◽  
Pearlitic Steel ◽  
Processing Method ◽  
Atomic Mobility ◽  
High Carbon ◽  
Pulsed Electric Current ◽  
Electropulsing Treatment ◽  
Ferrite Grain Size

Electropulsing treatment was applied to high carbon pearlitic steel to assess the effects of the treatment on microstructure and properties. Ferrite recrystallisation and cementite spheroidisation were induced in samples treated at pulse duration and frequency greater than 40μs and 50Hz, respectively. Ferrite grain size of electropulsed samples was refined compared to similarly annealed samples. The results are explained through a combination of heating and athermal dislocation and atomic mobility effects. With optimisation, electropulsing may offer an improved annealing processing method.

The Synthesis and Characteristics of Homogenously Dispersed CNT-Al2O3 Nanocomposites by the Thermal CVD Method and Pulsed Electric Current Sintering Process

2007 ◽  
Vol 121-123 ◽  
pp. 295-298 ◽  
Author(s):  
S.H. Yoo ◽  
J.K. Yang ◽  
Sung Tag Oh ◽  
Kae Myung Kang ◽  
Sung Goon Kang ◽  
...  
Keyword(s):  
Electric Current ◽  
Selective Reduction ◽  
Chemical Vapor ◽  
Metal Catalyst ◽  
Sintering Process ◽  
Composite Powders ◽  
Reduction Processes ◽  
Pulsed Electric Current ◽  
Nanocomposite Powders ◽  
Pulse Electric

An optimum route to synthesize Al2O3-based composite powders with a homogeneous dispersion of carbon nanotubes (CNTs) was investigated. CNT/Metal/Al2O3 nanocomposite powders were fabricated by thermal chemical vapor deposition (CVD) over a metal catalyst homogeneously dispersed into an Al2O3 matrix by the means of chemical and selective reduction processes. The nanocomposite powders were densified by Pulse Electric Current Sintering (PECS). The experimental results show that the CNT/Metal/Al2O3 nanocomposites have unique electrical properties.

Fabrication of a porous material with a porosity gradient by a pulsed electric current sintering process

2003 ◽  
Vol 9 (6) ◽  
pp. 599-603 ◽  
Author(s):  
Myung-Jin Suk ◽  
Sung-II Choi ◽  
Ji-Soon Kim ◽  
Young Do Kim ◽  
Young-Soon Kwon
Keyword(s):  
Porous Material ◽  
Electric Current ◽  
Sintering Process ◽  
Pulsed Electric Current
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