Effect of ZrB₂ content on phase assemblage and mechanical properties of Si₃N₄–ZrB₂ ceramics prepared at low temperature

Abstract

Based on the previous work on Si3N4–ZrB2 [Wu et al. J Eur Ceram Soc;2017,37:4217], the influence of ZrB2 addition on the phase and microstructure evolution of Si3N4–ZrB2 composites was emphatically investigated, and the mechanical properties were compared with pure Si3N4 ceramics. It was revealed that the ratio of β‐ to (α+β)‐Si3N4 significantly increased from 14.3% in pure Si3N4 ceramics to 39.8% in Si3N4 with 15 vol% ZrB2 addition, indicating that the introduction of ZrB2 promoted α‐ to β‐Si3N4 phase transformation. As a consequence, the microstructure of the composite showed the bimodal distribution, containing both elongated and equiaxed Si3N4 grains. For the pure Si3N4, Vickers hardness, fracture toughness and flexural strength was 22.8 GPa, 7.6 MPa m1/2, and 334.5 MPa, respectively. In contrast, the composite of Si3N4–30 vol% ZrB2 simultaneously possessed an excellent combination of mechanical properties: 19.5 GPa in hardness, 9.8 MPa m1/2 in toughness and 702.0 MPa in strength. Present study suggested that Si3N4‐based ceramics with high hardness, high toughness, and high strength could be obtained by the combination of appropriate ZrB2 content and low hot‐pressing temperature.

Temperature‐dependent mechanical and oxidation behavior of in situ formed ZrN/ZrO2‐containing Si3N4‐based composite

“…17,18 Among many additives, zirconium-based compounds (e.g., ZrB 2 , ZrC, ZrN, and ZrO 2 ) are regarded as ideal candidates with remarkable mechanical and high-temperature stability. [19][20][21] Guo et al 22 prepared a ZrB 2 -containing Si 3 N 4 -based composite at a low temperature of 1500 • C. It was found that the addition of ZrB 2 promoted the phase transition of Si 3 N 4 from α to β, and the obtained composite exhibited improved fracture toughness and bending strength of 9.8 MPa⋅m 1/2 and 702.0 MPa, respectively. Sayyadi-Shahraki et al 23 Although promising, the methods involving processing and preparation of ceramic composites still face practical difficulties, which weaken the final properties of the ceramic composite.…”

“…Among many additives, zirconium‐based compounds (e.g., ZrB 2 , ZrC, ZrN, and ZrO 2 ) are regarded as ideal candidates with remarkable mechanical and high‐temperature stability 19–21 . Guo et al 22 . prepared a ZrB 2 ‐containing Si 3 N 4 ‐based composite at a low temperature of 1500°C.…”

Cutting performance and wear characteristics of Si3N4–SiCw–HfB2 ceramic cutting tools in turning of ductile cast iron

“…On the other hand, it was reported that the incorporation of transition metal borides could lower the densification temperature and enhance fracture toughness while maintaining high hardness. [25][26][27] The transition metal cations of M 4+ and B 2− in the boride (e.g., ZrB 2 , 25 TiB 2 , 26 and HfB 2 27 ) can react with Si 3 N 4 , SiO 2 , and sintering aids to form liquid phase, reducing the viscosity of the liquid phase, resulting in low-temperature sintering and promoting α-Si 3 N 4 to β-Si 3 N 4 phase transformation. 28 Among these borides, HfB 2 exhibited the significant promotion effect on the lowtemperature densification and phase transformation of Si 3 N 4 ceramics.…”

“…Presently, Si 3 N 4 –SiC w ceramics still faced challenges such as high densification temperature and low hardness. On the other hand, it was reported that the incorporation of transition metal borides could lower the densification temperature and enhance fracture toughness while maintaining high hardness 25–27 . The transition metal cations of M 4+ and B 2− in the boride (e.g., ZrB 2 , 25 TiB 2 , 26 and HfB 2 27 ) can react with Si 3 N 4 , SiO 2 , and sintering aids to form liquid phase, reducing the viscosity of the liquid phase, resulting in low‐temperature sintering and promoting α‐Si 3 N 4 to β‐Si 3 N 4 phase transformation 28 .…”

Digital Light Processing 3D Printing of Surface-oxidized Si3N4 Coated by Silane Coupling Agent

“…Silicon nitride (Si 3 N 4 ) ceramic, one of the best comprehensive performance structural ceramics, have been widely used in high-temperature process industry, such as military, aerospace and civil engineering industries, due to its excellent hardness, high bending strength, good chemical stability and superior hightemperature resistance [1,2]. Traditional manufacturing methods to obtain customer-designed and complex-shaped Si 3 N 4 parts always rely on slip casting and dry-pressing molding.…”