不同碳形態之碳/鋁複材之熱物性研究

Abstract

本論文探討之碳/鋁複合材料之目的即在開發一種高熱傳導率、低膨脹係數和低密度的碳/鋁複合材料。隨著資訊產品效能的提升，散熱難度也愈趨困難，整個電子產業對散熱的需求更形迫切。在所有先進散熱材料中，碳/鋁複合材料由於具有高熱傳導，同時具有比鋁、銅等具有較低的密度與熱膨脹係數，非常具潛力的散熱材料。 具有優越的熱傳導率，同時具有低的密度與熱膨脹係數的散熱材料，是現階段競相開發研究的方向。本文針對幾種不同高性能的碳材料，如1D碳纖維材料、發泡碳材料、鑽石顆粒材料，將鋁材利用較低成本的壓力鑄造成形方式，進行碳/鋁複材成形後的熱物理特性究。 應用壓力滲透製程開發出高體積分率(>60%)的1D碳纖維/鋁複材熱傳導率可達634 W/m•K(纖維方向)，密度在2.2 g/cm3，熱膨脹係數則在7.7μm/moC，碳纖維強化的體積分率介於60%~70%。鑽石/鋁複材熱傳導率可達770 W/m•K(纖維方向)，密度在3.1 g/cm3，熱膨脹係數則在7.2μm/moC。

The purpose of this study is to develop a high thermal dissipation density, low thermal expansion and low density composite for IC component. Along with the trends of increasing performance and reducing size of the electronic devices, thermal dissipation becomes one of the most urgent problem to be solved. This has lead to the requirement of developing a high performance material with high thermal conductivity better than conventional aluminum or copper. One of these high performance materials is a aluminum based carbon (fiber) reinforced composite. In this study, we discussed the thermal physical properties of several carbon fibers, carbon foam and diamond particles reinforced composites. The result reveals that pressure infiltration fabricated 1D carbon fiber/Al composite has a volume fraction of 60%, a thermal conductivity of 634 W/m•k in fiber direction , a density of 2.2g/cm3 and coefficient thermal expansion (CTE) of 7.74μm/m℃ in fiber direction. Diamond/Al composite has a volume fraction of 57%, a thermal conductivity of 770W/m•k in fiber direction , a density of 3.1g/cm3 and coefficient thermal expansion (CTE) of 7.2μm/m℃ .