预置硅构建金刚石/铝复合材料耐潮高导热界面及其冶金形为

Lightweight diamond/aluminum composite with a super-high thermal conductivity is the third generation electronic packaging materials. However, the brittle and easily deliquescent phase Al4C3 at the interface not only reduce the mechanical properties severely, but also restrict their long-term stability especially in wet environment condition. In this project, silicon will be preset on the surface of diamond particles through coating technology and thermal treatment. Then the diamond/aluminum composite will be prepared by means of low pressure infiltration method. On the one hand, inhibit the Al4C3 phase by aluminum silicon alloy melt which is formed during the infiltration process at the interface. On the other hand, built a stable high thermal conductance silicon carbide interface, via the genetic effect of the initial presetting silicon carbide interface, during the infiltration-solidification process. Study on the interface metallurgy behavior of the diamond/aluminum composite in preparation of infiltration process, and built a theoretical model to describe the diffusion/enrichment behavior of the silicon element at the interface. Based on the above researches, the project can demonstrate the inhibition mechanism of nucleation and growth of the Al4C3 phase as well as the mechanism of optimizing composite interface via interfacial metallurgy method. It is conductive to prolonging the service life of diamond/aluminum composite with high thermal conductivity and enriching and improving the interfacial metallurgy theory.

轻质金刚石/铝复合材料是目前广泛应用的超高导热电子封装材料之一，然而金刚石/铝界面易形成脆性易潮解Al4C3相，不仅严重降低其力学性能，而且为其在潮湿环境下的使役稳定性埋下了隐患。本项目拟采用金刚石表面包覆和后续热处理将Si和SiC预置在金刚石/铝间，经低压熔渗法制备高体积分数金刚石复合材料，一方面通过Si在界面微区熔浸形成铝硅合金熔液，抑制Al4C3相生成；另一方面通过热处理预置的SiC初始界面，实现熔渗凝固过程遗传诱导构建复合材料高导热稳定的SiC界面。研究金刚石/铝复合材料熔渗制备过程中的界面冶金过程，建立预置硅元素在界面处扩散及富集的理论模型，阐明脆性易潮解相Al4C3形核、长大的抑制机理，揭示界面冶金优化复合材料高导热性能的机制，以实现高导热金刚石/铝复合材料使役的长效化。该项目的开展为丰富和完善界面冶金理论提供范例，进而推动界面冶金学科分支的建立和发展。

轻质金刚石/铝复合材料是目前广泛应用的超高导热电子封装材料之一。然而，金刚石/铝界面易形成脆性易潮解Al4C3相，不仅严重降低其力学性能，而且为其在潮湿环境下的使役稳定性埋下了隐患。本项目采用磁控溅射法和粉末混烧法，在金刚石表面预置了硅层、铝硅双层、纳米级碳化硅层、微米级碳化硅层，建立了硅预置层制备及热处理工艺与金刚石初始及界面结构的调控机制，提出了一种金刚石表面低温合成碳化硅的新方法，发现Al4C3相作为一个中间相在低温合成碳化硅的过程中起到了至关重要的作用。将这些不同预置层被用作金刚石/铝复合材料界面层，采用熔渗法制备了高体积分数的金刚石复合材料。通过控制熔渗过程中的界面冶金反应，构建了耐铝液冲刷的稳定的SiC界面结构，有效的阻断了金刚石与铝液的直接接触。阐明了碳化硅界面层能抑制脆性易潮解相Al4C3形成的抑制机理。通过预置的纳米级和微米的SiC层，实现了熔渗凝固过程遗传诱导构建复合材料高导热的SiC界面的构建，解决金刚石/铝复合材料低热导与易潮解的难题。本项目的研究结果表明，以体积分数为55%的纳米级碳化硅包覆金刚石制备铝基复合材料，其热导率达到了666 W·m-1·K-1，经500 h的泡水处理后，其热导率仅降低了6.31%。定量分析表明复合材料界面处仅有1.23wt.%的Al4C3。选取高质量的微米级碳化硅包覆金刚石作为复合材料的增强相，复合材料的热导率可达711 W·m-1·K-1，其界面处的Al4C3含量仅有0.5wt.%。本项目揭示界面冶金优化复合材料高导热性能的机制，以实现高导热金刚石/铝复合材料使役的长效化。该项目的开展为丰富和完善界面冶金理论提供范例，进而推动界面冶金学科分支的建立和发展。本项目发表论文7篇，申请专利2项，培养研究生5名。