The effect of graphite surface modification on the thermal conductivity(TC) and bending strength of graphite flakes/Al composites(Gf/Al) prepared by gas pressure infiltration were investigated. Al3 Ni and Al4C3 phase ...The effect of graphite surface modification on the thermal conductivity(TC) and bending strength of graphite flakes/Al composites(Gf/Al) prepared by gas pressure infiltration were investigated. Al3 Ni and Al4C3 phase may form at the interface in Ni-coated Gf/Al and uncoated Gf/Al composites, respectively, while the Al-Cu compound cannot be observed in Cu-coated Gf/Al composites. The Cu and Ni coatings enhance TC and the bending strength of the composites in the meantime. TC of Cu-coated Gf/Al composites reach 515 Wm^-1·K^-1 with 75 vol% Gf, which are higher than that of Ni-coated Gf/Al. Meanwhile, due to Al3 Ni at the interface, the bending strength of Ni-coated Gf/Al composites are far more than those of the uncoated and Cu-coated Gf/Al with the same content of Gf. The results indicate that metal-coated Gf can effectively improve the interfacial bonding between Gf and Al.展开更多
Nickel-coated graphite flakes/copper（GN/Cu） composites were fabricated by spark plasma sintering with the surface of graphite flakes（GFs） being modified by Ni–P electroless plating. The effects of the phase trans...Nickel-coated graphite flakes/copper（GN/Cu） composites were fabricated by spark plasma sintering with the surface of graphite flakes（GFs） being modified by Ni–P electroless plating. The effects of the phase transition of the amorphous Ni–P plating and of Ni diffusion into the Cu matrix on the densification behavior, interfacial microstructure, and thermal conductivity（TC） of the GN/Cu composites were systematically investigated. The introduction of Ni–P electroless plating efficiently reduced the densification temperature of uncoated GF/Cu composites from 850 to 650℃ and slightly increased the TC of the X–Y basal plane of the GF/Cu composites with 20 vol%–30 vol% graphite flakes. However, when the graphite flake content was greater than 30 vol%, the TC of the GF/Cu composites decreased with the introduction of Ni–P plating as a result of the combined effect of the improved heat-transfer interface with the transition layer, P generated at the interface, and the diffusion of Ni into the matrix. Given the effect of the Ni content on the TC of the Cu matrix and on the interface thermal resistance, a modified effective medium approximation model was used to predict the TC of the prepared GF/Cu composites.展开更多
通过真空热压烧结制备出高石墨含量的鳞片石墨/铜复合材料。研究了高石墨含量对鳞片石墨/铜复合材料微观结构和性能的影响。结果表明,随着石墨体积分数的增加(72.08 vol.%~93.34 vol.%),复合材料的密度降低(4.07~2.63 g cm^-3);电导率降...通过真空热压烧结制备出高石墨含量的鳞片石墨/铜复合材料。研究了高石墨含量对鳞片石墨/铜复合材料微观结构和性能的影响。结果表明,随着石墨体积分数的增加(72.08 vol.%~93.34 vol.%),复合材料的密度降低(4.07~2.63 g cm^-3);电导率降低(14.71%~2.45%国际退火铜标准);面向热导率先增加后降低,在石墨体积分数为82.6%时,面向热导率达到最大值为663.73 W m^-1K^-1;面向热膨胀系数降低(6.6×10^-6~2.2×10^-6K^-1);抗弯强度降低(42.48~14.63 MPa),抗压强度降低(45.75~20.46 MPa)。鳞片石墨在复合材料中高度取向排列,分布均匀。并对预测复合材料的热导率模型进行修正,发现测量结果和模型预测结果相吻合。展开更多
基金Funded by the Research Fund of the State Key Laboratory of Solidification Processing(NWPU),China(No.126-QP-2015).
文摘The effect of graphite surface modification on the thermal conductivity(TC) and bending strength of graphite flakes/Al composites(Gf/Al) prepared by gas pressure infiltration were investigated. Al3 Ni and Al4C3 phase may form at the interface in Ni-coated Gf/Al and uncoated Gf/Al composites, respectively, while the Al-Cu compound cannot be observed in Cu-coated Gf/Al composites. The Cu and Ni coatings enhance TC and the bending strength of the composites in the meantime. TC of Cu-coated Gf/Al composites reach 515 Wm^-1·K^-1 with 75 vol% Gf, which are higher than that of Ni-coated Gf/Al. Meanwhile, due to Al3 Ni at the interface, the bending strength of Ni-coated Gf/Al composites are far more than those of the uncoated and Cu-coated Gf/Al with the same content of Gf. The results indicate that metal-coated Gf can effectively improve the interfacial bonding between Gf and Al.
基金financially supported by the National Natural Science Foundation of China (No. 51374028)Fundamental Research Funds for the Central Universities (FRF-GF-17-B37)
文摘Nickel-coated graphite flakes/copper（GN/Cu） composites were fabricated by spark plasma sintering with the surface of graphite flakes（GFs） being modified by Ni–P electroless plating. The effects of the phase transition of the amorphous Ni–P plating and of Ni diffusion into the Cu matrix on the densification behavior, interfacial microstructure, and thermal conductivity（TC） of the GN/Cu composites were systematically investigated. The introduction of Ni–P electroless plating efficiently reduced the densification temperature of uncoated GF/Cu composites from 850 to 650℃ and slightly increased the TC of the X–Y basal plane of the GF/Cu composites with 20 vol%–30 vol% graphite flakes. However, when the graphite flake content was greater than 30 vol%, the TC of the GF/Cu composites decreased with the introduction of Ni–P plating as a result of the combined effect of the improved heat-transfer interface with the transition layer, P generated at the interface, and the diffusion of Ni into the matrix. Given the effect of the Ni content on the TC of the Cu matrix and on the interface thermal resistance, a modified effective medium approximation model was used to predict the TC of the prepared GF/Cu composites.
文摘通过真空热压烧结制备出高石墨含量的鳞片石墨/铜复合材料。研究了高石墨含量对鳞片石墨/铜复合材料微观结构和性能的影响。结果表明,随着石墨体积分数的增加(72.08 vol.%~93.34 vol.%),复合材料的密度降低(4.07~2.63 g cm^-3);电导率降低(14.71%~2.45%国际退火铜标准);面向热导率先增加后降低,在石墨体积分数为82.6%时,面向热导率达到最大值为663.73 W m^-1K^-1;面向热膨胀系数降低(6.6×10^-6~2.2×10^-6K^-1);抗弯强度降低(42.48~14.63 MPa),抗压强度降低(45.75~20.46 MPa)。鳞片石墨在复合材料中高度取向排列,分布均匀。并对预测复合材料的热导率模型进行修正,发现测量结果和模型预测结果相吻合。
