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通过钛酸酯偶联剂处理氮化铝(AlN)粉末,采用机械分散和超声波分散相结合的方法,制得环氧树脂/AlN复合材料。实验表明,钛酸酯偶联剂能有效地改善AlN粉末的表面性能,偶联剂质量分数为6%时,改性效果最好;AlN填料质量分数为10% ̄20%时,复合材料的冲击韧性较好。冲击断口形貌分析表明,河流状裂纹越窄,数量和分支越多,扩展路径越长,冲击韧性越好,A l N填料改性效果也越好。 相似文献
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研究了壳聚糖纺丝原液在真空脱泡和静置脱泡条件下的表观牯度和特性粘数的变化规律,讨论了尿素、醋酸钠等添加剂对纺丝原液性能的影响,在模拟纺丝设备上进行了纺丝,对纤维力学性能进行了初步分析.结果表明:真空脱泡条件下,壳聚糖纺丝原液粘度随脱泡时间的增加呈先下降后上升的趋势;在静置脱泡条件下,原液粘度呈下降趋势,随着时间的增加,其粘度下降趋缓;在壳聚糖纺丝原液中加入醋酸钠可提高原液的粘度,加速冻胶的形成;加入尿素,纺丝原液粘度下降,纺丝原液中的醋酸钠与壳聚糖摩尔比为0.2~0.4时,纤维力学性能较好. 相似文献
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研究影响气压烧结α/β-sialon复相材料相组成、显微结构及力学性能的基本因素.采用三阶段气压烧结α/β-sialon工艺,能有效控制气相分解产物生成,消除样品鼓泡现象,而有利于致密化.研究了Si3N4粒度及相组成、AlN粒度对气压烧结α/β-sialon的烧结、相组成、显微结构及力学性能产生的不同程度影响.细Si3N4原料因氧含量增加,使相组成向β相方向偏移;较细的AlN原料有利于烧结致密化和材料性能的提高,但要防止样品鼓泡现象;较粗的AlN原料因为增加瞬时过饱和度而使材料中出现明显晶粒异常长大现象,而使显微结构部分晶粒粗化.埋粉中添加适量AlN可以有效地消除样品鼓泡,但埋粉中AlN添加量过多,样品失重增大,微气孔增加. 相似文献
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《Ceramics International》2022,48(8):10438-10446
Ceramic-polymer composites with good thermal conductivity, low dielectric constant and low dielectric loss have significant applicability in microelectronics and wireless communication systems. However, traditional thermal conductivity ceramic-polymer composites – realized simply through the random dispersion of spherical or near-spherical ceramic powder fillers – cannot have both high thermal conductivity and good electrical insulation, which greatly hinders their practical application. In this study, we first used metallic Al powder corroded by ultrasonic cavitation as the aluminium source, and then prepared spherical aluminium nitride (AlN) powders with many nano petals grown on the surface using the melamine-assisted nitriding method; subsequently, the ice-template method was utilized to construct a three-dimensional (3D) AlN framework with vertical columnar holes, and finally, nanoflower-like AlN-epoxy (EP) composites were prepared by vacuum infiltration. The unique nano petal structures on the surface of AlN powder and the welding between AlN nano-petals during vacuum sintering increased the contact area between nanoflower-like AlN powders and lowered their contact thermal resistance. Moreover, the construction of vertical AlN channels was conducive to the formtion of thermally conductive pathways in AlN-epoxy composites. As a result, we obtained ceramic-polymer composites with improved thermal conductivity, among which the composites with 20 vol% nanoflower-like AlN powder had the highest thermal conductivity – 2.26 W/m·K – compared to a pure matrix, which is equivalent to an enhancement of 830%. 相似文献
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Mechanical,thermal, and dielectric properties of aluminum nitride/glass fiber/epoxy resin composites
The treated hybrid fillers of aluminum nitride/glass fibers (AlN/GF) were performed to prepare the AlN/GF/epoxy composites by casting method. Results showed that the flexural and impact strength of the composites were increased firstly, but decreased with the excessive addition of AlN. The mechanical properties were optimal with 5 wt% treated AlN. The thermal conductivities of the composites were improved with the increasing content of AlN, and the thermal conductive coefficient λ was 1.412 W/mK with 70 wt% treated AlN, about seven times higher than that of pure epoxy resin. The dielectric constant and dielectric loss of the composites were increased with the increasing content of AlN. For a given AlN/GF hybrid fillers loading, the surface treatment of AlN/GF hybrid fillers exhibited a positive effect on the mechanical properties and thermal conductivities of the composites. POLYM. COMPOS., 35:381–385, 2014. © 2013 Society of Plastics Engineers 相似文献
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《Ceramics International》2022,48(21):32001-32008
With rapid technological advancements, efficient thermal management is becoming increasingly important to sustain the stable operation of electronic devices. In this study, aluminum nitride (AlN) fillers with various acrylate monomers were subjected to two types of silane surface treatments to prepare composites with a high loading of AlN filler (65 wt%). The acrylates—isobornyl acrylate (IBOA), 1,4-butanediol diacrylate (BDDA), and trimethylolpropane triacrylate (TMPTA)—were mixed with bisphenol A ethoxylate dimethacrylate (Bis-EMA) as an oligomer, and phenylbis (2,4,6-trimethylbenzoyl)phosphine oxide (BAPO) as a photo-initiator in different proportions to obtain resin matrices. Pristine AlN and AlN functionalized with APTES and MPS were used as fillers. The effect of the acrylate functional group in silanes on the thermal and mechanical properties of the acrylate resin was explored. The thermal conductivities of the IBOA/AlN/APTES and IBOA/AlN/TMPTA composites with a high loading of the filler functionalized with APTES and MPS were 1.34 and 1.57 W/(m?K), respectively, 4.15 and 5.28 times higher than that of the composite with neat resin. The enhanced filler–matrix compatibility increased the tensile strength of the composites. The findings highlighted that silane functionalization of AlN can enhance the thermal conductivity and mechanical properties of the composite. 相似文献
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Shoichi Kume Ikuko Yamada Koji Watari Isao Harada Kenshi Mitsuishi 《Journal of the American Ceramic Society》2009,92(S1):S153-S156
To increase the thermal conductivity of polymer/ceramic composites, aluminum nitride (AlN) granules were added as a ceramic filler. Granules, sintered at 1850°C for 24 h, showed a very high conductivity of 266±26 W (m·°C)−1 , as measured by a thermal microscope equipped with thermoreflectant and periodic heating techniques. This conductivity exceeds 80% of the theoretical value of AlN. Ceramic fillers consisting of the obtained AlN granules and commercially available hexagonal boron nitride particles (h-BN) powder plus polyimide resins were mixed and then molded at 100 MPa and 420°C in a vacuum. The resultant composite showed a high conductivity of 9.3 W (m·°C)−1 . This study demonstrates that a high-thermal-conductivity filler effectively enhances the conductivity of polymer/ceramic composites. 相似文献
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The effects of boron nitride (BN) and aluminum nitride fillers on polyamide 6 (PA6) hybrid polymer composites were investigated. In particular, the thermal and electrical conductivity, thermal transition, thermal degradation, mechanical and morphological properties and chemical bonds characteristic of the materials with crystal structure of BN and aluminum nitride (AlN) filled PA6 prepared at different concentrations were characterized. Thermal conductivity of hybrid systems revealed a 1.6-fold gain compared to neat PA6. The highest thermal conductivity value was obtained for the composite containing 50 vol% additives (1.040 W/m K). A slight improvement in electrical conductive properties of composites appears and the highest value was obtained for the 50 vol% filled composite with only an increase by 3%. The microstructure of these composites revealed a homogeneous dispersion of AlN and BN additives in PA6 matrix. For all composites, one visible melting peak around 220°C related to the α-form crystals of PA6 was detected in correlation with the X-ray diffraction results. An improved thermal stability was obtained for 10 vol% AlN/BN filled PA6 composite (from 405.41°C to 409.68°C). The tensile strength results of all composites were found to be approximately 22% lower than pure PA6. 相似文献
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Three composites based on cyanate (CE) resin, aluminum nitride (AlN), surface‐treated aluminum nitride [AlN(KH560)], and silicon dioxide (SiO2) for microelectronic packaging, coded as AlN/CE, AlN(KH560)‐SiO2(KH560)/CE, and AlN‐SiO2/CE composite, respectively, were developed for the first time. The thermal conductivity and dielectric constant of all composites were investigated in detail. Results show that properties of fillers in composites have great influence on the thermal conductivity and dielectric constant of composites. Surface treatment of fillers is beneficial to increase the thermal conductivity or reduce dielectric constant of the composites. Comparing with binary composite, when the filler content is high, ternary composites possess lower thermal conductivity and dielectric constant. The reasons leading to these outcomes are discussed intensively. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers 相似文献
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The effects of ultrasonic irradiation on the rheology, structure, and properties of PP/inorganic filler composites were studied. Scanning electron microscopy showed that ultrasound increased the orientation degrees of acicular fillers to the flow direction. WAXD indicated that ultrasound vibration induced sheet fillers orient with its surface perpendicular to the direction of the ultrasound vibration. The orderly rearrangements of fillers in the polymer melt induced by ultrasound vibration can reduce the steric hindrances in the flow field and increase the flowability of the PP/inorganic filler composites. The effect of ultrasound on reducing the apparent viscosities is very prominent, especially at lower shear rate. Ultrasound has an even more marked effect on reducing the apparent viscosities of composites containing fillers of larger size. With ultrasound vibration, the mechanical properties of the composites are also improved because of the orientation and uniform dispersion of fillers in the matrix. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1553–1560, 2005 相似文献
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《Ceramics International》2023,49(4):5707-5719
As one of the key components of electronic devices, thermal management materials (TMMs) with high thermal conductivity are essential to ensure their safety and long service life. For polymer-based TMMs, AlN is one of the preferred fillers, but it has some drawbacks such as high cost and easy hydrolysis. Herein, a controllable and continuously oriented three-dimensional AlN skeleton (3D-AlNNS) was in-situ transformed from a low-cost 3D Al-containing skeleton (3D-AlNS) by combining the ice-templating and nitriding reaction sintering. Subsequently, AlN/epoxy composites were obtained by a vacuum infiltration. The composite containing 39.69 vol% AlN had the highest thermal conductivity of 4.29 W m?1·K?1, which was 21.45 times higher than that of pure epoxy. The composite substrates showed excellent heat dissipation performance in practical applications due to their high thermal conductivity. The continuous directional alignment of AlN powders in the 3D skeleton and intersection of AlN whiskers between the skeleton walls produced in-situ contributed to the formation of effective multichannel heat transferring paths and improvement in thermal conductivity. This novel approach has the advantages of low-cost, short processing time, simple operation and repeatability, and provides a new idea for developing heat-conducting polymer composites, which can also be extended to the preparation of similar TMMs. 相似文献
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Sheng‐Yen Wu Yuan‐Li Huang Chen‐Chi M Ma Siu‐Ming Yuen Chih‐Chun Teng Shin‐Yi Yang Chorng H. Twu 《Polymer International》2012,61(7):1084-1093
A series of polyimide‐based nanocomposites containing polyimide‐grafted multi‐walled carbon nanotubes (PI‐g MWCNTs) and silane‐modified ceramic (aluminium nitride (AlN)) were prepared. The mechanical, thermal and electrical properties of hybrid PI‐g MWCNT/AlN/polyetherimide nanocomposites were investigated. After polyimide grafting modification, the PI‐g MWCNTs showed good dispersion and wettability in the polyetherimide matrix and imparted excellent mechanical, electrical and thermal properties. The utilization of the hybrid filler was found to be effective in increasing the thermal conductivity of the composites due to the enhanced connectivity due to the high‐aspect‐ratio MWCNT filler. The use of spherical AlN filler and PI‐g MWCNT filler resulted in composite materials with enhanced thermal conductivity and low coefficient of thermal expansion. Results indicated that the hybrid PI‐g MWCNT and AlN fillers incorporated into the polyetherimide matrix enhanced significantly the thermal stability, thermal conductivity and mechanical properties of the matrix. Copyright © 2012 Society of Chemical Industry 相似文献
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Reactive Synthesis and Phase Stability Investigations in the Aluminum Nitride–Silicon Carbide System
Ellen M. Carrillo-Heian Hongyong Xue Manshi Ohyanagi Zuhair A. Munir 《Journal of the American Ceramic Society》2000,83(5):1103-1107
The effect of AlN on the structure formation of SiC was investigated. SiC was synthesized in the presence of AlN under vacuum at 1500°C, and the result was cubic SiC. The synthesis of AlN–SiC composites through the reaction Si3 N4 + 4Al + 3C = 3SiC + 4AlN was also investigated and compared with synthesis via field-activated self-propagating combustion (FASHS). Reactants were heated in a vacuum furnace at temperatures ranging from 1130° to 1650°C. Below 1650°C, the reaction is not complete and at this temperature the product phases are AlN and cubic SiC. At 1650°C, the product contained an outer layer which contained β-SiC only and an inner region which contained AlN and cubic SiC. 2H-SiC and AlN composites synthesized via field-activated self-propagating combustion were annealed at 1700°C under vacuum. The AlN dissociated and evaporated and the 2H-SiC transformed to the cubic β phase. Reasons for the differences in products of furnace heating and FASHS are discussed. 相似文献