TiB2-Al2O3 composite powders were produced by self-propagating high-temperature synthesis（SHS） method with reductive process from B2O3-TiO2-AI system. X-ray diffraction（XRD） and scanning electron microscopy（SEM...TiB2-Al2O3 composite powders were produced by self-propagating high-temperature synthesis（SHS） method with reductive process from B2O3-TiO2-AI system. X-ray diffraction（XRD） and scanning electron microscopy（SEM） analyses show the presence of TiB2 and Al2O3 only in the composite powders produced by SHS. The powders are uniform and free-agglomerate. Transmission electron microscopy （TEM） and high resolution electron microscopy （HREM） observation of microstructure of the composite powders indicate that the interfaces of the TiB2-Al2O3 bond well, without any interfacial reaction products. It is proposed that the good interfacial bonding of the composite powders can be resulted from the TiB2 particles crystallizing and growing on the Al2O3 particles surface with surface defects acting as nucleation centers.展开更多
To improve the properties of low-carbonization of MgO–C refractories,the introduction of composite additives is an effective strategy.Al_(2)O_(3)–SiC composite powder was prepared from clay using electromagnetic ind...To improve the properties of low-carbonization of MgO–C refractories,the introduction of composite additives is an effective strategy.Al_(2)O_(3)–SiC composite powder was prepared from clay using electromagnetic induction heating and carbon embedded methods.Further,the Al_(2)O_(3)–SiC composite powder synthesized by electromagnetic induction heating at 600 A was added into low-carbon MgO–C refractories(4 wt.%)to improve their properties.The results showed that when the addition amount of Al_(2)O_(3)–SiC composite powder is within the range of 2.5–5.0 wt.%,the properties of low-carbon MgO–C samples were significantly improved,e.g.,the apparent porosity of 7.58%–8.04%,the bulk density of 2.98–2.99 g cm-3,the cold compressive strength of 55.72–57.93 MPa,the residual strength after three air quenching at 1100°C of 74.86%–78.04%,and the decarburized layer depth after oxidized at 1400°C for 2 h of 14.03–14.87 mm.Consequently,the idea for the rapid synthesis of Al_(2)O_(3)–SiC composite powder provides an alternative low-carbon MgO–C refractories performance optimization strategy.展开更多
Warm compaction was employed to fabricate a Ti3SiC2 particulate reinforced copper matrix composite for electro-friction application. Copper matrix composite reinforced with 5wt% of copper-coated Ti3SiC2 particulates w...Warm compaction was employed to fabricate a Ti3SiC2 particulate reinforced copper matrix composite for electro-friction application. Copper matrix composite reinforced with 5wt% of copper-coated Ti3SiC2 particulates were prepared by compacting mixed powder with a pressure of 700 MPa at 145 ℃, and then sintered at 1000 ℃ under cracked ammonia atmosphere for 60 min. In order to improve the density, rolling process was applied on the sintered samples, their density, hardness, electrical conductivity, ultimate tensile strength and tribological behaviors were studied. Results showed that the rolled composite with 30% deformation has a density of 8.28 g/cm3, a hardness of 1060 MPa (HB), an ultimate tensile strength of 288 MPa, an electrical resistivity of 7.0 ×10-8 Ω·m and a friction coefficient of 0.17.展开更多
文摘TiB2-Al2O3 composite powders were produced by self-propagating high-temperature synthesis（SHS） method with reductive process from B2O3-TiO2-AI system. X-ray diffraction（XRD） and scanning electron microscopy（SEM） analyses show the presence of TiB2 and Al2O3 only in the composite powders produced by SHS. The powders are uniform and free-agglomerate. Transmission electron microscopy （TEM） and high resolution electron microscopy （HREM） observation of microstructure of the composite powders indicate that the interfaces of the TiB2-Al2O3 bond well, without any interfacial reaction products. It is proposed that the good interfacial bonding of the composite powders can be resulted from the TiB2 particles crystallizing and growing on the Al2O3 particles surface with surface defects acting as nucleation centers.
基金This work was financially supported by the National Natural Science Foundation of China(Grant Nos.U20A20239 and U1908227)the Fundamental Research Funds for the Central Universities(Grant No.N2125002)the open research fund for State Key Laboratory of Advance Refractories(Grant No.SKLAR202001).
文摘To improve the properties of low-carbonization of MgO–C refractories,the introduction of composite additives is an effective strategy.Al_(2)O_(3)–SiC composite powder was prepared from clay using electromagnetic induction heating and carbon embedded methods.Further,the Al_(2)O_(3)–SiC composite powder synthesized by electromagnetic induction heating at 600 A was added into low-carbon MgO–C refractories(4 wt.%)to improve their properties.The results showed that when the addition amount of Al_(2)O_(3)–SiC composite powder is within the range of 2.5–5.0 wt.%,the properties of low-carbon MgO–C samples were significantly improved,e.g.,the apparent porosity of 7.58%–8.04%,the bulk density of 2.98–2.99 g cm-3,the cold compressive strength of 55.72–57.93 MPa,the residual strength after three air quenching at 1100°C of 74.86%–78.04%,and the decarburized layer depth after oxidized at 1400°C for 2 h of 14.03–14.87 mm.Consequently,the idea for the rapid synthesis of Al_(2)O_(3)–SiC composite powder provides an alternative low-carbon MgO–C refractories performance optimization strategy.
基金National Natural Science Foundation of China (50774036, 51074077)Guangdong Provincial Natural Science Foundation (8151064101000029)
文摘Warm compaction was employed to fabricate a Ti3SiC2 particulate reinforced copper matrix composite for electro-friction application. Copper matrix composite reinforced with 5wt% of copper-coated Ti3SiC2 particulates were prepared by compacting mixed powder with a pressure of 700 MPa at 145 ℃, and then sintered at 1000 ℃ under cracked ammonia atmosphere for 60 min. In order to improve the density, rolling process was applied on the sintered samples, their density, hardness, electrical conductivity, ultimate tensile strength and tribological behaviors were studied. Results showed that the rolled composite with 30% deformation has a density of 8.28 g/cm3, a hardness of 1060 MPa (HB), an ultimate tensile strength of 288 MPa, an electrical resistivity of 7.0 ×10-8 Ω·m and a friction coefficient of 0.17.
