Open AccessPreparation of Transparent MgAl2O4 Spinel by Pulsed Electric Current Sintering Using Two-step Heating Method
Author(s) -
Yen Ngoc Nguyen,
Hai Minh Le,
Tu Anh Dao,
Hung N. Tran,
Tùng Lâm Nguyễn,
Thang Hong Le,
Khanh Quoc Dang
Publication year - 2021
Publication title -
acta metallurgica slovaca
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.277
H-Index - 13
eISSN - 1338-1156
pISSN - 1335-1532
DOI - 10.36547/ams.27.4.1212
Subject(s) - sintering , materials science , spinel , dwell time , ceramic , transmittance , vickers hardness test , combustion , one step , two step , composite material , metallurgy , chemical engineering , microstructure , optoelectronics , chemistry , combinatorial chemistry , engineering , medicine , clinical psychology , organic chemistry
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.