铜/金刚石复合材料热导率正交实验研究

采用高温高压法制备了铜/金刚石复合材料.通过正交实验法研究了复合材料中金刚石粒度的不同尺寸和对应的体积比、铜和金刚石的体积比及保压保温时间等各种因素对复合材料热导率的影响.结果表明:铜和金刚石的体积比因素对热导率的影响最大,而金刚石不同粒度的体积比影响最小.获得了基于提高复合材料热导率的最佳制备工艺条件是,配料中金刚石粒度尺寸为75μm和250 μm,金刚石大小粒度的配料体积比为1∶4,铜和金刚石的配料体积比为7∶3和保压保温时间为2h,该工艺条件下制备的复合材料热导率为238.18 W/(m·K).     

高温高压烧结金刚石-铜复合材料的研究

采用高温高压烧结工艺制备了金刚石体积分数为80%的金刚石-铜复合材料。研究了金刚石颗粒大小、烧结温度、烧结时间等因素对复合材料成分、界面状态和热导率的影响。结果表明:金刚石颗粒直径为80μm时,在高温高压条件下可获得热导率高达639 W.m-1.K-1的金刚石-铜复合材料。当金刚石体积分数一定时,存在一临界粒径,随金刚石颗粒直径增大复合材料热导率先增大后减小。恰当的烧结温度和时间有助于获得黏结良好的界面和高热导率。     

金刚石/铜复合材料热导率研究

采用高温高压法制备出金刚石/铜复合材料,并对复合材料的显微组织及性能进行了研究.结果表明,采用高温高压法制备的金刚石/铜复合材料,组织致密;复合材料的热导率随金刚石含量的增加而下降,这主要是由于界面热阻对复合材料热导率的影响.     

高导热金刚石/铜复合材料的导热研究进展

金刚石/铜复合材料具有密度低、热导率高及热膨胀系数可调等优点,且与新一代芯片具有良好的热匹配性能,因此其在高热流密度电子封装领域具有非常广泛的应用前景。然而由于金刚石与铜界面润湿性差,界面热阻高,导致材料热导率比铜还低,限制了其应用。为了改善其界面润湿性,国内外通过在金刚石表面金属化或对铜基体预合金化等手段来修饰复合材料界面,以提高金刚石/铜复合材料的热导率。本文综述了表面改性、导热模型相关的界面理论以及有限元模拟的研究进展,讨论了制备工艺、导热模型和未来发展的关键方向,总结了金刚石添加量、颗粒尺寸等制备参数对其微观组织结构和导热性能的影响规律。     

镀钨金刚石/铜复合材料的制备及导热性能（英文）

使用热扩散法在金刚石表面镀钨,并采用不同工艺参数制备镀钨金刚石/铜复合材料,观察不同样品的微观形貌,并使用激光闪射法测量样品的热导率,探索制备高热导率金刚石/铜复合材料的最佳工艺参数。研究结果表明,在金刚石表面镀钨可以改善界面结合,当镀覆时间为60 min时,镀层完整、均匀、平整,样品的热导率达到486 W/(m·K)。镀层的完整性和均匀性比镀层厚度更为重要。进一步对镀钨金刚石进行退火处理后,镀层与金刚石之间的冶金结合增强,制备得到的复合材料的热导率提高到559 W/(m·K)。     

超高压熔渗烧结法制备金刚石/铜复合材料

采用超高压熔渗法制备金刚石/铜复合材料,研究了烧结温度、烧结压力及保温时间等因素对复合材料成分、界面状态和热导率的影响,利用XRD、SEM对金刚石/铜复合材料的相组成和微观形貌进行分析。结果表明:复合材料的相对密度随着烧结温度、烧结压力及金刚石颗粒粒径的增大而增加,且熔渗合金的复合材料的热导率高于熔渗铜的复合材料的热导率。当金刚石粒径为200μm,熔渗烧结温度在1300℃,压力为5 GPa,保温5 min时,得到最高的热导率,为870 W/(m·K)。     

表面镀钨层对金刚石/铜复合材料热导率的影响

采用真空微蒸发-扩散镀技术,在金刚石表面镀覆不同厚度的钨层,并结合真空熔渗法制备金刚石铜复合材料。通过X射线衍射分析镀覆层相结构,采用扫描电镜观察镀覆层表面微观形貌和复合材料中金刚石与铜界面结合形貌,分析金刚石表面镀钨层组织、结构及厚度对金刚石/铜复合材料热导率的影响。结果表明:金刚石表面镀覆钨能改善与基体的润湿性;随着镀覆层均匀性和厚度增加,复合材料热导率先增加后减小;完整均匀的镀覆层可以获得较高界面热导。     

金刚石/铝导热复合材料的显微组织与热力学性能

以高温盐浴法对金刚石表面进行镀硅处理来改善金刚石和铝基之间的界面结合,镀硅后的金刚石颗粒表面略显粗糙,表面的镀层均匀;采用真空热压烧结法制备高导热镀硅金刚石/铝复合材料,研究了烧结温度和金刚石体积分数对复合材料相对密度和热导率的影响。随着金刚石体积分数的增加,复合材料的相对密度和热导均呈现先升后降的趋势,当金刚石体积分数为45%时,复合材料的热导率达到最大,为558 W/mK。     

高温高压法制备金刚石/铜复合材料的研究

采用高温高压法制备金刚石/铜复合材料。研究金刚石体积分数、烧结压力、保温时间、烧结温度、金刚石表面金属化对金刚石/铜复合材料热导率及热膨胀系数的影响。实验表明:金刚石体积分数70%,烧结压力2 GPa,烧结时间300 s,烧结温度1200℃时,金刚石/铜复合材料热导率达426 W/（m·K）。      

W对金刚石/铜复合材料组织及性能影响

采用金刚石与W粉混合制备预制坯,然后通过无压浸渗制备金刚石/铜复合材料。采用SEM、XRD、激光热导仪等手段,分析了不同的掺杂量对金刚石/铜复合材料的组织、界面结构及热导率的影响。结果表明,随着W的加入,金刚石与铜的界面结合良好,复合材料的组织更加致密,W元素在界面处富集生成WC、W2C等碳化物。随着掺杂量的增加,复合材料的热导率先升高后下降,最高达到450 W·m~(-1)·K~(-1)。     

金刚石/铜复合材料在电子封装材料领域的研究进展

金刚石/铜复合材料作为新型电子封装材料受到了广泛的关注。综述了金刚石/铜复合材料作为电子封装材料的国内外研究现状,介绍了金刚石/铜复合材料的制备工艺,并从材料科学的原理综述了该复合材料主要性能指标（热导率）的影响因素,同时对金刚石/铜复合材料的界面问题进行了分析,最后对金刚石/铜复合材料的未来应用进行了展望。     

并联导热结构的金刚石/铜基复合材料的制备

为提高金刚石/铜基复合材料的导热性能,在芯材表面预先化学气相沉积(CVD)高质量金刚石膜,获得柱状金刚石棒,再将其垂直排列,填充铜粉后真空热压烧结,制备并联结构的金刚石/铜基复合材料。分别采用激光拉曼光谱(Raman)与扫描电子显微镜(SEM)对CVD金刚石膜的生长进行分析,并通过数值分析讨论复合材料的热性能。结果表明:金刚石/铜基复合材料结构致密,密度为9.51g/cm3;CVD金刚石膜构成连续的导热通道,产生并联式导热,复合材料的热导率为392.78 W/(m·K)。     

Effect of powder mixing process on the microstructure and thermal conductivity of Al/diamond composites fabricated by spark plasma sintering

Two powder mixing processes, mechanical mixing (MM) and mechanical alloying (MA), were used to prepare mixed Al/diamond powders, which were subsequently consolidated using spark plasma sintering (SPS) to produce bulk Al/diamond composites. The effects of the powder mixing process on the morphologies of the mixed powders, the microstructure and the thermal conductivity of the composites were investigated. The results show that the powder mixing process can significantly affect the microstructure and the thermal conductivity of the composites. Agglomerations of the particles occurred in mixed powders using MM for 30 min, which led to high pore content and weak interfacial bonding in the composites and resulted in low relative density and low thermal conductivity for the composites. Mixed powders of homogeneous distribution of diamond particles could be obtained using MA for 10 min and MM for 2 h. The composite prepared through MA indicated a high relative density but low thermal conductivity due to its defects, such as damaged particles, Fe impurity, and local interfacial debonding, which were mainly introduced in the MA process. In contrast, the composite made by MM for 2 h demonstrated high relative density and an excellent thermal conductivity of 325 W·m-1·K-1, owing to its having few defects and strong interfacial bonding.     

添加稀土Nd改善金刚石/铜复合材料界面

目的添加稀土Nd改善金刚石/铜复合材料界面间的缺陷,抑制金刚石与铜之间的弱润湿性,增强复合材料的界面结合。方法采用放电等离子烧结(SPS)技术制备含有不同质量分数Nd的镀钛金刚石/铜复合材料,采用扫描电子显微镜观察界面处的微观形貌,采用X射线衍射仪和X射线能谱仪分析界面处组织,采用排水法测试复合材料的密度和致密度。结果添加稀土Nd后,金刚石-铜两相界面间促生了Cu_5Nd、NdCu_2、Cu_3Ti等相。界面间的Cu_5Nd、NdCu_2、Cu_3Ti、TiC填补了镀钛金刚石/铜复合材料界面处原有的空隙、孔洞等缺陷。未添加稀土Nd的镀钛金刚石/铜复合材料的密度为4.589 g/cm~3,致密度为81%;添加3wt%的Nd元素后,镀钛金刚石/铜复合材料的密度和致密度分别达到了5.569 g/cm~3和98%,密度较未添加Nd的复合材料提升了21%。随着Nd含量的增加,金刚石-铜界面间的缺陷逐渐减少,界面结合效果逐渐转好。结论稀土Nd极大地改善了镀钛金刚石/铜复合材料两相界面处的缺陷,很好地修饰了原本润湿性较差的金刚石-铜两相界面。添加Nd元素后,复合材料两相界面结合紧密。     

Microstructure and thermal conductivity of copper matrix composites reinforced with mixtures of diamond and SiC particles

The thermal conductivity of diamond hybrid SiC/Cu,diamond/Cu and SiC/Cu composite were calculated by using the extended differential effective medium (DEM) theoretical model in this paper.The effects of the particle volume fraction,the particle size and the volume ratio of the diamond particles to the total particles on the thermal conductivity of the composite were studied.The DEM theoretical calculation results show that,for the diamond hybrid SiC/Cu composite,when the particle volume fraction is above 46% and the volume ratio of the diamond particles to the SiC particles is above 13:12,the thermal conductivity of the composite can reach 500 W·m-1·K-1.The thermal conduc-tivity of the composite has little change when the particle size is above 200μm.The experimental results show that Ti can improve the wettability of the SiC and Cu.The thermal conductivity of the diamond hybrid SiCTi/Cu is almost two times better than that of the diamond hybrid SiC/Cu.It is feasible to predict the thermal conductivity of the composite by DEM theoretical model.     

Thermal conductivity of diamond/copper composites with a bimodal distribution of diamond particle sizes prepared by pressure infiltration method

The thermal conductivity of diamond/copper composites with bimodal particle sizes was studied.The composites were prepared through pressure infiltration of liquid copper into diamond preforms with a mixture of 40 and 100 μm-size diamonds.The permeability of the preforms with different coarse-to-fine volume ratios of diamonds was investigated.The thermal conductivity of the diamond/copper composites with bimodal size distribution was compared to the theoretical value derived from an analytical model developed by Chu.It is predicted that the diamond/copper composites could reach a higher thermal conductivity and their surface roughness could be improved by applying bimodal diamond particle sizes.     

Effect of Nanometer WC Coating on Thermal Conductivity of Diamond/6061 Composites

Diamond has poor interface tolerance with Al. To enhance interface bonding, in this study, tungsten carbide (WC) nanocoatings on the surface of diamond particles were prepared using sol-gel and in-situ reaction methods. WO₃ sol-gel with two concentrations, 0.2 mol/L, and 0.5 mol/L, was, respectively, coated on diamond particles, then sintered at 1250 °C for 2 h to produce WC nanocoatings. The concentration of 0.2 mol/L WO₃ sol-gel was not enough to cover the surface of the diamond completely, while 0.5 mol/L WO₃ sol-gel could fully cover it. Moreover, WO₃ was preferentially deposited on {100} planes of the diamond. WO₃ converted to WC in-situ nanocoatings after sintering due to the in-situ reaction of WO₃ and diamond. The diamond-reinforced Al composites with and without WC coating were fabricated by powder metallurgy. The diamond/Al composite without coating has a thermal conductivity of 584.7 W/mK, while the composite with a coating formed by 0.2 mol/L and 0.5 mol/L WO₃ sol-gel showed thermal conductivities of 626.1 W/mK and 584.2 W/mK, respectively. The moderate thickness of nanocoatings formed by 0.2 mol/L WO₃ sol-gel could enhance interface bonding, therefore improving thermal conductivity. The nanocoating produced by 0.5 mol/L WO₃ sol-gel cracked during the fabrication of the composite, leading to Al₁₂W formation and a decrease in thermal conductivity.