Joints between sintered silicon carbide （SSiC） were produced using a polysiloxane silicon resin YR3370 （GE Toshiba Silicones） as joining material. Samples were heat treated in a 99.99% nitrogen flux at temperature...Joints between sintered silicon carbide （SSiC） were produced using a polysiloxane silicon resin YR3370 （GE Toshiba Silicones） as joining material. Samples were heat treated in a 99.99% nitrogen flux at temperatures ranging from 1 100 ℃ to 1 300 ℃. Three point bending strength of the joint reached the maximum of 179 MPa as joined at 1 200℃. The joining layer is continuous, homogeneous and densified and has a thickness of 2 μm -5μm. The joining mechanism is that the amorphous silicon oxycarbide （SixOyCz） ceramic pyrolyzed from silicon resin YR3370 acts as an inorganic adhesive to SSiC substrate, which means the formation of the continuous Si-C bond structure between SixOyCz structure and SSiC substrate. Life prediction of the ceramic joint can be realized through the measurement of the critical time of the joint after the cyclic loading test.展开更多
Porous C/C-SiC composites were prepared through a two-step chemical vapor infiltration process,and a multi-interlayer joint of Li20-MgO-Al2O3-SiO2（LMAS） was applied to join C/C-SiC composites and lithium aluminum si...Porous C/C-SiC composites were prepared through a two-step chemical vapor infiltration process,and a multi-interlayer joint of Li20-MgO-Al2O3-SiO2（LMAS） was applied to join C/C-SiC composites and lithium aluminum silicate（LAS） glass ceramics by means of a vacuum hot-pressing technique.Plenty of SiC whiskers were generated in the pores of low-density C/C composites during chemical vapor deposition process,which is essentia! to form a zigzag interface structure between C/C-SiC substrate and the LMAS interlayer.The average shear strength of the LMAS joint was improved from 12.17 to 19.91 MPa after changing the composites from high-density C/C composites（1.75 g/cm3） with a CVD-SiC coating to the C/C-SiC composites with a low density（1.48 g/cm3）.The improvement of the joint strength is mainly attributed to the formation of the inlay structure at the SiC-C/C and SiC-LMAS interfaces.展开更多
Using newly developed Cu58Ni12Ti30 alloy as brazing filler metal, this paper has carried out the joining wxperiments of Si3N4 and the joint shength tests at room temperature.The joint brazed at 1,293K for 10 min exhib...Using newly developed Cu58Ni12Ti30 alloy as brazing filler metal, this paper has carried out the joining wxperiments of Si3N4 and the joint shength tests at room temperature.The joint brazed at 1,293K for 10 min exhibited the maximum strength value of 157.2 MPa.The microstructures of the joint cross-section were observed and the elements area distributions on the interface were examined by means of scanning electron microscope with X-ray wave-dispersion spectrometer.The phases formed in the joint were determined by X-ray diffraction analysis method.The results showed that during the brazing process the active element Ti diffused to the interfaces and reacted with Si3N4,resulted in forming the reaction products TiN NiTiSi, and Ti4Si3(or TiSi)on the interfaces.Some effects on the trend to produce these compounds were attempted to explain from α thermodynalic point of view.展开更多
Alumina specimens were joined together with thin aluminium interlayer at 750 and 900°C under different applied pressures and holding time in air. Flexural strength of the joints was then measured using a standard...Alumina specimens were joined together with thin aluminium interlayer at 750 and 900°C under different applied pressures and holding time in air. Flexural strength of the joints was then measured using a standard four-point bend test method. Characterization of the interface was carried out to correlate the increase in flexural strength with the applied pressure, holding temperature and time. The study showed that the strength of joint is affected by all three parameters, i.e., processing temperature, holding time as well as applied pressure.展开更多
基金National Key Fundamental R&D Plan (2004CB217808)National Natural Science Foundation of China (20271037)
文摘Joints between sintered silicon carbide （SSiC） were produced using a polysiloxane silicon resin YR3370 （GE Toshiba Silicones） as joining material. Samples were heat treated in a 99.99% nitrogen flux at temperatures ranging from 1 100 ℃ to 1 300 ℃. Three point bending strength of the joint reached the maximum of 179 MPa as joined at 1 200℃. The joining layer is continuous, homogeneous and densified and has a thickness of 2 μm -5μm. The joining mechanism is that the amorphous silicon oxycarbide （SixOyCz） ceramic pyrolyzed from silicon resin YR3370 acts as an inorganic adhesive to SSiC substrate, which means the formation of the continuous Si-C bond structure between SixOyCz structure and SSiC substrate. Life prediction of the ceramic joint can be realized through the measurement of the critical time of the joint after the cyclic loading test.
基金funding supported from the National Natural Science Foundation of China(Grant Nos.51221001 and 51222207)the "111" Project(Grant No.B08040)the Foundation of the National Excellent Doctoral Dissertation of China(No.201036)
文摘Porous C/C-SiC composites were prepared through a two-step chemical vapor infiltration process,and a multi-interlayer joint of Li20-MgO-Al2O3-SiO2（LMAS） was applied to join C/C-SiC composites and lithium aluminum silicate（LAS） glass ceramics by means of a vacuum hot-pressing technique.Plenty of SiC whiskers were generated in the pores of low-density C/C composites during chemical vapor deposition process,which is essentia! to form a zigzag interface structure between C/C-SiC substrate and the LMAS interlayer.The average shear strength of the LMAS joint was improved from 12.17 to 19.91 MPa after changing the composites from high-density C/C composites（1.75 g/cm3） with a CVD-SiC coating to the C/C-SiC composites with a low density（1.48 g/cm3）.The improvement of the joint strength is mainly attributed to the formation of the inlay structure at the SiC-C/C and SiC-LMAS interfaces.
文摘Using newly developed Cu58Ni12Ti30 alloy as brazing filler metal, this paper has carried out the joining wxperiments of Si3N4 and the joint shength tests at room temperature.The joint brazed at 1,293K for 10 min exhibited the maximum strength value of 157.2 MPa.The microstructures of the joint cross-section were observed and the elements area distributions on the interface were examined by means of scanning electron microscope with X-ray wave-dispersion spectrometer.The phases formed in the joint were determined by X-ray diffraction analysis method.The results showed that during the brazing process the active element Ti diffused to the interfaces and reacted with Si3N4,resulted in forming the reaction products TiN NiTiSi, and Ti4Si3(or TiSi)on the interfaces.Some effects on the trend to produce these compounds were attempted to explain from α thermodynalic point of view.
文摘Alumina specimens were joined together with thin aluminium interlayer at 750 and 900°C under different applied pressures and holding time in air. Flexural strength of the joints was then measured using a standard four-point bend test method. Characterization of the interface was carried out to correlate the increase in flexural strength with the applied pressure, holding temperature and time. The study showed that the strength of joint is affected by all three parameters, i.e., processing temperature, holding time as well as applied pressure.
