A novel ceramic cemented carbide compact insert was developed using hot pressing sintering technique. The surface layers of the sandwich material were ceramic and the middle layer was cemented carbide. The factors tha...A novel ceramic cemented carbide compact insert was developed using hot pressing sintering technique. The surface layers of the sandwich material were ceramic and the middle layer was cemented carbide. The factors that affect the properties of the compact insert were analyzed. Theoretical analyses and experiments indicated that the cemented carbide with greater elastic module and thermal expansion coefficient than ceramic should be used in the sandwich material in order to get high equivalent flexure strength and the geometric parameters of the compact insert are also important to its properties.展开更多
B_(4)C-SiC-TiB_(2)ceramics were prepared by in situ reactive hot-pressing sintering with TiSi_(2)as an additive.The reaction pathways of TiSi_(2)and B_(4)C were investigated.The sintering was found to be a multistep p...B_(4)C-SiC-TiB_(2)ceramics were prepared by in situ reactive hot-pressing sintering with TiSi_(2)as an additive.The reaction pathways of TiSi_(2)and B_(4)C were investigated.The sintering was found to be a multistep process.The reaction started at approximately 1000℃,and TiB_(2)was formed first.Part of Si and C started to react at 1300℃,and the unreacted Si melted at 1400℃to form a liquid phase.TiSi_(2)predominantly affected the intermediate sintering process of B_(4)C and increased the sintering rate.Due to the unique reaction process of TiSi_(2)and B_(4)C,a large number of aggregates composed of SiC and TiB_(2)were generated.The results showed that composite ceramics with the optimal flexural strength of 807 MPa,fracture toughness of 3.2 MPa·m1/2,and hardness of 32 GPa,were obtained when the TiSi_(2)content was 10 wt%.展开更多
In this paper,Si_(3)N_(4) was used as a novel solid-state sintering additive to prepare AION transparent ceramics with high transparency and flexural strength via the pressureless pre-sintering and hot isostatic press...In this paper,Si_(3)N_(4) was used as a novel solid-state sintering additive to prepare AION transparent ceramics with high transparency and flexural strength via the pressureless pre-sintering and hot isostatic pressing(HIP)method at a relatively low HIP temperature(1800℃).The effect of Si_(3)N_(4) content on the phase,microstructure,optical property,and flexural strength was investigated.The experimental results showed that a Si element was homogenously distributed in both pre-sintered and HIPed AION ceramics.The densification enhanced,the grain grew with the increasing Si_(3)N_(4) content in the pre-sintered AION ceramics,and all the samples became pore-free after HIP,which favor transparency.The AION ceramics doped with 0.10 wt%Si_(3)N_(4) had the highest transmittance of 83.8%at 600 nm and 85.6%at 2000 nm(4 mm in thickness),with flexural strength of 404 MPa,which were higher than those of the previous reports.展开更多
文摘A novel ceramic cemented carbide compact insert was developed using hot pressing sintering technique. The surface layers of the sandwich material were ceramic and the middle layer was cemented carbide. The factors that affect the properties of the compact insert were analyzed. Theoretical analyses and experiments indicated that the cemented carbide with greater elastic module and thermal expansion coefficient than ceramic should be used in the sandwich material in order to get high equivalent flexure strength and the geometric parameters of the compact insert are also important to its properties.
基金Funded by the National Natural Science Foundation of China(No.52002299)。
文摘B_(4)C-SiC-TiB_(2)ceramics were prepared by in situ reactive hot-pressing sintering with TiSi_(2)as an additive.The reaction pathways of TiSi_(2)and B_(4)C were investigated.The sintering was found to be a multistep process.The reaction started at approximately 1000℃,and TiB_(2)was formed first.Part of Si and C started to react at 1300℃,and the unreacted Si melted at 1400℃to form a liquid phase.TiSi_(2)predominantly affected the intermediate sintering process of B_(4)C and increased the sintering rate.Due to the unique reaction process of TiSi_(2)and B_(4)C,a large number of aggregates composed of SiC and TiB_(2)were generated.The results showed that composite ceramics with the optimal flexural strength of 807 MPa,fracture toughness of 3.2 MPa·m1/2,and hardness of 32 GPa,were obtained when the TiSi_(2)content was 10 wt%.
基金supported by the Natural Science Foundation of Shanghai(Grant No.19ZR1465000)the National Natural Science Foundation of China(Grant No.51902330).
文摘In this paper,Si_(3)N_(4) was used as a novel solid-state sintering additive to prepare AION transparent ceramics with high transparency and flexural strength via the pressureless pre-sintering and hot isostatic pressing(HIP)method at a relatively low HIP temperature(1800℃).The effect of Si_(3)N_(4) content on the phase,microstructure,optical property,and flexural strength was investigated.The experimental results showed that a Si element was homogenously distributed in both pre-sintered and HIPed AION ceramics.The densification enhanced,the grain grew with the increasing Si_(3)N_(4) content in the pre-sintered AION ceramics,and all the samples became pore-free after HIP,which favor transparency.The AION ceramics doped with 0.10 wt%Si_(3)N_(4) had the highest transmittance of 83.8%at 600 nm and 85.6%at 2000 nm(4 mm in thickness),with flexural strength of 404 MPa,which were higher than those of the previous reports.
