TY - JOUR
T1 - A novel ZrB2–C3N4 composite with improved mechanical properties
AU - Ahmadi, Zohre
AU - Zakeri, Mohammad
AU - Habibi-Yangjeh, Aziz
AU - Shahedi Asl, Mehdi
N1 - Publisher Copyright:
© 2019 Elsevier Ltd and Techna Group S.r.l.
PY - 2019/12/1
Y1 - 2019/12/1
N2 - In this research, a novel application for graphitic carbon nitride as the sintering aid and reinforcement was investigated. In this regard, g-C3N4 doped ZrB2-based ultrahigh temperature ceramic was fabricated by route of spark plasma sintering at 1850 °C under an applied pressure of 40 MPa for 6 min. Microstructure development, sinterability, and mechanical properties were studied and compared to the additive-free ZrB2. The sinterability was remarkably enhanced, and a fully-dense ceramic was obtained by addition of 5 wt% g-C3N4, in comparison with the monolithic ZrB2 with a relative density of 76.5%. The elimination of oxide surface impurities of ZrB2 (B2O3 and ZrO2) through chemical reactions with g-C3N4 and the formation of in-situ phases like ZrC and BN were confirmed by microstructural and phase analyses. Mechanical properties were enhanced with a small amount of g-C3N4 additive due to the densification improvement and prevention of grain growth. The values of hardness, indentation fracture toughness and flexural strength increased from 10.1 GPa, 1.9 MPa m½ and 187.6 MPa for monolithic ZrB2 to 16.2 GPa, 5.4 MPa m½ and 516.4 MPa for g-C3N4 doped ZrB2 ceramic.
AB - In this research, a novel application for graphitic carbon nitride as the sintering aid and reinforcement was investigated. In this regard, g-C3N4 doped ZrB2-based ultrahigh temperature ceramic was fabricated by route of spark plasma sintering at 1850 °C under an applied pressure of 40 MPa for 6 min. Microstructure development, sinterability, and mechanical properties were studied and compared to the additive-free ZrB2. The sinterability was remarkably enhanced, and a fully-dense ceramic was obtained by addition of 5 wt% g-C3N4, in comparison with the monolithic ZrB2 with a relative density of 76.5%. The elimination of oxide surface impurities of ZrB2 (B2O3 and ZrO2) through chemical reactions with g-C3N4 and the formation of in-situ phases like ZrC and BN were confirmed by microstructural and phase analyses. Mechanical properties were enhanced with a small amount of g-C3N4 additive due to the densification improvement and prevention of grain growth. The values of hardness, indentation fracture toughness and flexural strength increased from 10.1 GPa, 1.9 MPa m½ and 187.6 MPa for monolithic ZrB2 to 16.2 GPa, 5.4 MPa m½ and 516.4 MPa for g-C3N4 doped ZrB2 ceramic.
KW - Graphitic CN
KW - Mechanical properties
KW - Microstructure
KW - Spark plasma sintering
KW - ZrB
UR - http://www.scopus.com/inward/record.url?scp=85069054355&partnerID=8YFLogxK
U2 - 10.1016/j.ceramint.2019.07.144
DO - 10.1016/j.ceramint.2019.07.144
M3 - Article
AN - SCOPUS:85069054355
SN - 0272-8842
VL - 45
SP - 21512
EP - 21519
JO - Ceramics International
JF - Ceramics International
IS - 17
ER -