TY - JOUR
T1 - Reactive hot pressing of ZrB2-based composites with changes in ZrO2/SiC ratio and sintering conditions. Part I
T2 - Densification behavior
AU - Vafa, Nasser Pourmohammadie
AU - Shahedi Asl, Mehdi
AU - Jaberi Zamharir, Mehran
AU - Ghassemi Kakroudi, Mahdi
N1 - Publisher Copyright:
© 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.
PY - 2015/8/1
Y1 - 2015/8/1
N2 - ZrB2-SiC-ZrO2 composites were hot pressed in order to investigate the effects of adding nano-sized ZrO2 particles as well as the hot pressing parameters on the densification behavior of ZrB2-SiC composites. An L9 orthogonal array of the Taguchi method was employed to study the significance of each parameter such as the sintering temperature, time, the applied external pressure, and ZrO2/SiC volume ratio on the densification process. The statistical analyses revealed that among the mentioned parameters, the hot pressing temperature had a great influence over the densification. By being hot pressed at 1850 °C for 90 min under 16 MPa, fully dense ZrB2-based composites were obtained. The relative density of the composites decreased at first and then enhanced as a function of ZrO2/SiC ratio. Microstructural investigation of the fracture surfaces of the composites, which was carried out using the SEM analysis, showed the formation of new phases on the surfaces of SiC grains. The EDS and XRD analyses identified the ZrC as the newly formed interfacial phase due to the reaction between nano-ZrO2 and SiC. The ZrC acted as an adhesive interphase between the ZrB2/SiC grains, which could assist the sintering process.
AB - ZrB2-SiC-ZrO2 composites were hot pressed in order to investigate the effects of adding nano-sized ZrO2 particles as well as the hot pressing parameters on the densification behavior of ZrB2-SiC composites. An L9 orthogonal array of the Taguchi method was employed to study the significance of each parameter such as the sintering temperature, time, the applied external pressure, and ZrO2/SiC volume ratio on the densification process. The statistical analyses revealed that among the mentioned parameters, the hot pressing temperature had a great influence over the densification. By being hot pressed at 1850 °C for 90 min under 16 MPa, fully dense ZrB2-based composites were obtained. The relative density of the composites decreased at first and then enhanced as a function of ZrO2/SiC ratio. Microstructural investigation of the fracture surfaces of the composites, which was carried out using the SEM analysis, showed the formation of new phases on the surfaces of SiC grains. The EDS and XRD analyses identified the ZrC as the newly formed interfacial phase due to the reaction between nano-ZrO2 and SiC. The ZrC acted as an adhesive interphase between the ZrB2/SiC grains, which could assist the sintering process.
KW - Densification behavior
KW - Nano-sized zirconia
KW - Reactive hot pressing
KW - Silicon carbide
KW - Zirconium diboride
UR - http://www.scopus.com/inward/record.url?scp=84929265414&partnerID=8YFLogxK
U2 - 10.1016/j.ceramint.2015.03.033
DO - 10.1016/j.ceramint.2015.03.033
M3 - Article
AN - SCOPUS:84929265414
SN - 0272-8842
VL - 41
SP - 8388
EP - 8396
JO - Ceramics International
JF - Ceramics International
IS - 7
ER -