鈦添加量及燒結時間對無壓液相燒結鑽石銅基複合材料之界面微結構及熱性質的影響

Effect of Titanium Addition and Varying Sintering Time on the Interface Structure and Thermal Properties of Diamond/Cu Composites Fabricated by Pressureless Liquid Phase Sintering

鍾志育(Chih-Yu Chung)

指導教授 ： 林樹均

國立清華大學/工學院/材料科學工程學系/博士(2014年)

摘要

本實驗使用無壓液相燒結法製備鑽石銅基複合材料。由於金屬銅在鑽石表面上的潤濕性不佳，因此選擇添加活性元素至基材中，希望藉此改善界面間的潤濕性，進而得到具有良好的熱傳導性質的複合材料。而經由實驗結果得知，以鈦元素的添加具有最好的提升界面潤濕的效果。更進一步研究鑽石體積分率變化、鈦添加量多寡，以及燒結時間對於整體複合材料熱性質的影響，並且在改變燒結時間的實驗中，利用 SEM 以及 TEM 的觀測，分析鑽石與基材間的界面成長方式，以建立界面成長的機制。由界面微結構分析指出，界面層主要是由碳化鈦所組成，且界面的厚度會隨燒結時間及鈦含量的增加而變厚，對於複材的熱傳導性質有著決定性的影響。所製備出的複合材料，在鑽石體積分率 50%、鈦添加量 0.6 at% 的條件下，其熱傳導係數可高達 620 W/mK，熱膨脹係數為 6.9 ppm/K；而在鑽石顆粒雙粒徑的添加系統中，鑽石總體積分率 60% 的複材，其熱傳導值更可高達 683 W/mK。經由理論計算，本實驗製備的複合材料熱傳導值可高達理論值的 77 ~ 86%，熱膨脹係數則介於 Kerner upper line 與 Kener lower line 之間，代表此製成製備的複合材料性質良好，幾乎可與理論值吻合。另外，由於此製程為一無壓燒結製程，無須加壓設備，將可大幅降低設備成本，並且製程簡便，可用於大量生產，使此鑽石/銅基複合材料在電子構裝散熱材的應用上更具潛力。

關鍵字

複合材料 ； 熱傳導係數 ； 熱膨脹係數 ； 液相燒結法

並列摘要

In this study, minor-addition elements such as Si, Co, Cr, W, Mo and Ti were added into matrix to improve the wettability between the diamonds and Cu matrix. The pressureless liquid phase sintering technique adopted in this study provides a low-cost method for producing diamond/Cu composites with high potential for industrial mass-production. Thermal properties of the diamond/Cu-Ti composites fabricated by pressureless liquid phase sintering at 1373 K with variations in Ti contents and in sintering times were thoroughly investigated. SEM and TEM analyses were
utilized to study the growth mechanism of the TiC at the interface between diamonds and Cu matrix. A probable mechanism of the interface structure formation was proposed. The composites exhibited thermal conductivity as high as 620 W/m•K for 50 vol% diamond/Cu-0.6 at% Ti composite with diamond particle size of 300 µm. This value comes up to 85% of the thermal conductivity calculated by Hasselman and Johnson (H-J) theoretical analysis. Under these conditions a suitable coefficient of thermal expansion of 6.9 ppm/K was obtained.

並列關鍵字

Composite ； Thermal conductivity ； Coefficient of thermal expansion ； Liquid phase sintering

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