Diamond films were successfully synthesized on aluminum nitride(AlN) ceramic substrates by hot filament chemical vapor deposition(HFCVD) method. It is notices that the thermal conductivity of the diamond film/aluminum...Diamond films were successfully synthesized on aluminum nitride(AlN) ceramic substrates by hot filament chemical vapor deposition(HFCVD) method. It is notices that the thermal conductivity of the diamond film/aluminum nitride ceramic(DF/AlN) composite has reached 2.04 W/cm·K, 73%greater than that of AlN ceramic. Compared with the measurement of scanning electron microscopy(SEM) and Raman spectroscopy, the influence of diamond films on the thermal conductivity of the composites was pointed out. The adhesion and the stresses of diamond films were also studied. The unusual stability and very good adhesion of diamond films on AlN ceramic substrates obtained are attributed to the formation of aluminum carbide.展开更多
Aluminum oxide(Al_(2)O_(3))ceramics have been widely utilized as circuit substrates owing to their exceptional performance.In this study,boron nitride microribbon(BNMR)/Al_(2)O_(3)composite ceramics are prepared using...Aluminum oxide(Al_(2)O_(3))ceramics have been widely utilized as circuit substrates owing to their exceptional performance.In this study,boron nitride microribbon(BNMR)/Al_(2)O_(3)composite ceramics are prepared using spark plasma sintering(SPS).This study examines the effect of varying the amount of toughened phase BNMR on the density,mechanical properties,dielectric constant,and thermal conductivity of BNMR/Al_(2)O_(3)composite ceramics while also exploring the mechanisms behind the toughening and increased thermal conductivity of the fabricated ceramics.The results showed that for a BNMR content of 5 wt%,BNMR/Al_(2)O_(3)composite ceramics displayed more enhanced characteristics than pure Al_(2)O_(3)ceramics.In particular,the relative density,hardness,fracture toughness,and bending strength were 99.95%±0.025%,34.11±1.5 GPa,5.42±0.21 MPa·m^(1/2),and 375±2.5 MPa,respectively.These values represent increases of 0.76%,70%,35%,and 25%,respectively,compared with the corresponding values for pure Al_(2)O_(3)ceramics.Furthermore,during the SPS process,BNMRs are subjected to high temperatures and pressures,resulting in the bending and deformation of the Al_(2)O_(3)matrix;this leads to the formation of special thermal pathways within it.The dielectric constant of the composite ceramics decreased by 25.6%,whereas the thermal conductivity increased by 45.6%compared with that of the pure Al_(2)O_(3)ceramics.The results of this study provide valuable insights into ways of enhancing the performance of Al_(2)O_(3)-based ceramic substrates by incorporating novel BNMRs as a second phase.These improvements are significant for potential applications in circuit substrates and related fields that require high-performance materials with improved mechanical properties and thermal conductivities.展开更多
文摘Diamond films were successfully synthesized on aluminum nitride(AlN) ceramic substrates by hot filament chemical vapor deposition(HFCVD) method. It is notices that the thermal conductivity of the diamond film/aluminum nitride ceramic(DF/AlN) composite has reached 2.04 W/cm·K, 73%greater than that of AlN ceramic. Compared with the measurement of scanning electron microscopy(SEM) and Raman spectroscopy, the influence of diamond films on the thermal conductivity of the composites was pointed out. The adhesion and the stresses of diamond films were also studied. The unusual stability and very good adhesion of diamond films on AlN ceramic substrates obtained are attributed to the formation of aluminum carbide.
基金the financial support from National Natural Science Foundation of China(No.52262010)the Guangxi Natural Science Foundation of China(No.2023GXNSFAA026384)the Guilin Scientific Research and Technology Development Program(No.2020011203-3).
文摘Aluminum oxide(Al_(2)O_(3))ceramics have been widely utilized as circuit substrates owing to their exceptional performance.In this study,boron nitride microribbon(BNMR)/Al_(2)O_(3)composite ceramics are prepared using spark plasma sintering(SPS).This study examines the effect of varying the amount of toughened phase BNMR on the density,mechanical properties,dielectric constant,and thermal conductivity of BNMR/Al_(2)O_(3)composite ceramics while also exploring the mechanisms behind the toughening and increased thermal conductivity of the fabricated ceramics.The results showed that for a BNMR content of 5 wt%,BNMR/Al_(2)O_(3)composite ceramics displayed more enhanced characteristics than pure Al_(2)O_(3)ceramics.In particular,the relative density,hardness,fracture toughness,and bending strength were 99.95%±0.025%,34.11±1.5 GPa,5.42±0.21 MPa·m^(1/2),and 375±2.5 MPa,respectively.These values represent increases of 0.76%,70%,35%,and 25%,respectively,compared with the corresponding values for pure Al_(2)O_(3)ceramics.Furthermore,during the SPS process,BNMRs are subjected to high temperatures and pressures,resulting in the bending and deformation of the Al_(2)O_(3)matrix;this leads to the formation of special thermal pathways within it.The dielectric constant of the composite ceramics decreased by 25.6%,whereas the thermal conductivity increased by 45.6%compared with that of the pure Al_(2)O_(3)ceramics.The results of this study provide valuable insights into ways of enhancing the performance of Al_(2)O_(3)-based ceramic substrates by incorporating novel BNMRs as a second phase.These improvements are significant for potential applications in circuit substrates and related fields that require high-performance materials with improved mechanical properties and thermal conductivities.
基金Strategic Priority Research Program of the Chinese Academy of Sciences(XDB20010300,XDA21010204)Adv.Energy Sci.&Technol.Guangdong Lab(Open laboratory)。
