Fabrication and microstructures of functional gradient SiBCN–Nb composite by hot pressing

et al. 2020

J Adv Ceram

Self Cite

The in situ nano Ta4HfC5 reinforced SiBCN-Ta4HfC5 composite ceramics were prepared by a combination of two-step mechanical alloying and reactive hot-pressing sintering. The microstructural evolution and mechanical properties of the resulting SiBCN-Ta4HfC5 were studied. After the first-step milling of 30 h, the raw materials of TaC and HfC underwent crushing, cold sintering, and short-range interdiffusion to finally obtain the high pure nano Ta4HfC5. A hybrid structure of amorphous SiBCN and nano Ta4HfC5 was obtained by adopting a second-step ball-milling. After reactive hot-pressing sintering, amorphous SiBCN has crystallized to 3C-SiC, 6H-SiC, and turbostratic BN(C) phases and Ta4HfC5 retained the form of the nanostructure. With the in situ generations of 2.5 wt% Ta4HfC5, Ta4HfC5 is preferentially distributed within the turbostratic BN(C); however, as Ta4HfC5 content further raised to 10 wt%, it mainly distributed in the grain-boundary of BN(C) and SiC. The introduction of Ta4HfC5 nanocrystals can effectively improve the flexural strength and fracture toughness of SiBCN ceramics, reaching to 344.1 MPa and 4.52 MPa·m1/2, respectively. This work has solved the problems of uneven distribution of ultra-high temperature phases in the ceramic matrix, which is beneficial to the real applications of SiBCN ceramics.

Section: Introduction mentioning

confidence: 99%

Microstructural evolution and mechanical properties of in situ nano Ta4HfC5 reinforced SiBCN composite ceramics

et al. 2020

J Adv Ceram

Self Cite

“…As documented, the introduction of ultra-high temperature ceramics (UHTCs) into SiBCN ceramic matrix, is considered to be an effective strategy to improve the mechanical performance of SiBCN ceramics [15][16][17][18] . In previous attempts, the microstructural evolution and thermal stability of the porous PDCs ZrB 2 -SiBCN and HfN-SiBCN composite ceramics have been investigated [19][20] .…”

Section: Introductionmentioning

confidence: 99%

Microstructural evolution and mechanical properties of in situ nano Ta4HfC5 reinforced SiBCN composite ceramics

et al. 2020

Preprint

Self Cite

In this paper, the in situ nano Ta 4 HfC 5 reinforced SiBCN-Ta 4 HfC 5 composite ceramics were prepared by a combination of two-step mechanical alloying and reactive hot-pressing sintering. The microstructural evolution and mechanical properties of the SiBCN-Ha 4 HfC 5 were studied. After the first-step milling of 30 h, the raw materials of TaC and HfC undergone crushing, cold sintering and short-range interdiffusion to finally obtain the high pure nano Ta 4 HfC 5 . A hybrid structure of amorphous SiBCN and nano Ta 4 HfC 5 was obtained by adopting a second-step ball-milling. After reactive hot-pressing sintering, amorphous SiBCN has crystallized to nano SiC and turbostratic BN(C) phases while Ta 4 HfC 5 retained the form of nano structure. With the in situ generation of 2.5 wt% Ta 4 HfC 5 , Ta 4 HfC 5 is preferentially distributed within the turbostratic BN(C); however, as Ta 4 HfC 5 content further raised to 10 wt%, it mainly distributed in the grain-boundary of BN(C) and SiC. The introduction of Ta 4 HfC 5 nanocrystals can effectively improve the flexural strength and fracture toughness of SiBCN ceramics, reaching to 344.1 MPa and 4.52 MPa•m 1/2 , respectively.

“…As documented, the introduction of ultra-high temperature ceramics (UHTCs) into SiBCN ceramic matrix, is believed to be an effective strategy to improve the mechanical performance of SiBCN ceramics [11][12][13][14] .…”

Section: Introductionmentioning

confidence: 99%

Microstructural evolution and mechanical properties of in situ nano Ta4HfC5 reinforced SiBCN composite ceramics

et al. 2020

Preprint

Self Cite

In this paper, the in situ nano Ta4HfC5 reinforced SiBCN-Ta4HfC5 composite ceramics were prepared by a combination of two-step mechanical alloying and reactive hot-pressing sintering. The microstructural evolution and mechanical properties of the resulting SiBCN-Ta4HfC5 were studied. After the first-step milling of 30 h, the raw materials of TaC and HfC undergone crushing, cold sintering and short-range interdiffusion to finally obtain the high pure nano Ta4HfC5. A hybrid structure of amorphous SiBCN and nano Ta4HfC5 was obtained by adopting a second-step ball-milling. After reactive hot-pressing sintering, amorphous SiBCN has crystallized to nano SiC and turbostratic BN(C) phases while Ta4HfC5 retained the form of nano structure. With the in situ generation of 2.5 wt% Ta4HfC5, Ta4HfC5 is preferentially distributed within the turbostratic BN(C); however, as Ta4HfC5 content further raised to 10 wt%, it mainly distributed in the grain-boundary of BN(C) and SiC. The introduction of Ta4HfC5 nanocrystals can effectively improve the flexural strength and fracture toughness of SiBCN ceramics, reaching to 344.1 MPa and 4.52 MPam1/2, respectively. This work has solved the problems of uneven distribution of ultra-high temperature phase in ceramic matrix, which is beneficial to the real applications of SiBCN ceramics.