以黃藤製作SiC/鋁矽合金複合材料之研究

Fabrication of SiC/aluminum-silicon alloy composite from rattan bio-charcoal

羅小雯(Xiao-Wen Lo)

指導教授 ： 林永仁

大同大學/工程學院/材料工程學系所/碩士(2007年)

摘要

本研究的主旨是利用黃藤製備陶瓷/金屬複合材料。首先將黃藤在Ar氣氛中經過碳化處理後，形成藤木炭，再將適量矽粉及鋁合金塊材與藤木炭一起放置在氧化鋁坩鍋裡，在高溫和保護氣體下，一次處理即合成碳化矽/鋁矽合金複合材料。 實驗結果發現，在反應溫度1500℃，可成功製備具黃藤結構之碳化矽。而此多孔性碳化矽是由直徑250μm、6-20μm、3μm等三種不同大小的連通孔洞所構成的。在1500℃持溫16小時合成的多孔性碳化矽，具有低密度(體密度為1.51g/cm3)，高孔隙率(開放性孔隙率為44±1％)，其比表面積為5.5m2/g，抗壓強度為44±2MPa，抗彎強度為13±5MPa。 溫度在1300℃~1500℃，初始鋁與矽的比例為Al-10at%Si、Al-20at%Si和Al-30at%Si的液相滲透試片，各有不同的液相滲透現象。越高溫及含矽量越少的試片越容易產生碳化鋁，實驗結果顯示最佳的滲透溫度為1400℃，成分為 Al-20at%Si。由試片密度結果顯示，在常壓液相滲透過程中，滲透量大致上會隨著滲透時間的增長而增加，但滲透時間3小時後，試片趨近於飽和。在滲透時間為5小時，其試片的體密度可達2.27 g/cm3，開放性孔隙率為19±1％，抗壓強度為316±5MPa，抗彎強度為138±5MPa，而觀察複合材料的破斷面是以沿晶破壞為主。

關鍵字

黃藤 ； SiC/鋁矽合金

並列摘要

The purpose of this research is to fabricate ceramic/metal composite material from rattan. Rattan was first carbonized in Ar to form charcoal. Then proper amount of Si powder and pieces of aluminum alloy were put into the alumina crucibles with the charcoal. After heat-treatment in Ar and at high temperature, composites of silicon carbide/aluminum-silicon alloy could be obtained. The results of the experiments showed that silicon carbide with the structure of rattan could be produced after reaction at 1500. The porous ℃silicon carbide preserved the structure of the rattan and was made up of three kinds of interconnected holes with the diameters of 250µm, 6-20µm, and 3µm, respectively. The porous silicon carbide after heat-treatment at 1500 for 16℃ hours had bulk density 1.51g/cm3, open porosity 44±1%, specific surface area 5.5 m2/g, compressive strength 44±2MPa, and flexural strength 13±5 MPa. As for the fabrication of SiC/Al-Si composites, the heat-treatment temperatures ranged from 1300~1500.℃℃ The initial proportion of 2024 aluminum alloy and silicon ranged from Al-10at%Si to Al-30at%Si. During the high temperature reaction, Si reacted to form SiC and Si-Al alloy melted to infiltrate into the porous SiC. However, at higher temperature and less silicon concentration, aluminum carbide would form. The result of this research indicated that the proper conditions for SiC/Al-Si composite fabrication without noticeable aluminum carbide was 1400and Al℃-20at%Si. Under such conditions and heat-treatment for 5 hours, the bulk density of the sample was 2.27 g/cm3, the open porosity was 19±1%, the compressive strength was 316±5MPa and the flexural strength was 138±5MPa. Furthermore, it was also noted that intergranular fracture was the main feature of the composite material during fracture.

並列關鍵字

rattan ； SiC/aluminum-silicon

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