組織和導(dǎo)熱性能的影響
(1. 合肥工業(yè)大學(xué) 材料科學(xué)與工程學(xué)院，合肥230009; 2.安徽理工大學(xué) 材料科學(xué)與工程學(xué)院，淮南232001;
3. 安徽省有色金屬材料與加工工程實驗室，合肥230009)
摘 要: 利用無壓浸滲法制備高體積分?jǐn)?shù)的SiCp/Al復(fù)合材料，采用X射線衍射(XRD)、掃描電鏡(SEM)和能譜(EDS)對預(yù)制塊和復(fù)合材料的相組成及微觀組織進(jìn)行分析，研究不同造孔劑對復(fù)合材料導(dǎo)熱性能的影響。結(jié)果表明：在900 ℃時，以Fe(NO3)3·9H2O為造孔劑制備的復(fù)合材料組織均勻，致密度好，無明顯氣孔缺陷，界面反應(yīng)產(chǎn)物為Mg2Si、MgAl2O4和Fe；以Ni(NO3)2·6H2O為造孔劑制備的復(fù)合材料致密度差，有明顯氣孔缺陷，界面反應(yīng)產(chǎn)物為Mg2Si、MgAl2O4和NiO，且熱導(dǎo)率和相對密度均低于以Fe(NO3)3·9H2O為造孔劑制備的復(fù)合材料的，其原因是Fe2O3和鋁液發(fā)生鋁熱反應(yīng)改善基體和SiC的潤濕性，從而提高復(fù)合材料的致密度。
關(guān)鍵字: 造孔劑；SiCp/Al復(fù)合材料；無壓浸滲；微觀組織；熱導(dǎo)率
（1. School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009, China;
2. School of Materials Science and Engineering, Anhui University of Science and Technology, Huainan 232001, China;
3. Nonferrous Metals Materials and Process Engineering Laboratory of Anhui Province,
Hefei University of Technology, Hefei 230009, China）
Abstract:The high volume fraction SiCp/Al composites were prepared by pressureless infiltration, and the effects of Fe(NO3)3·9H2O and Ni(NO3)2·6H2O on thermal conductivity of the composites were studied. The microstructures of the SiC porous preforms and the composites sintered at 900 ℃ were characterized by XRD, SEM and EDS. The results show that the microstructures of SiCp/Al-10Si-8Mg composite with Fe(NO3)3·9H2O as pore-forming agent are more homogeneous than those with Ni(NO3)2·6H2O pore-forming agent, and the compactness of the former is higher than that of the latter. The interfacial reactive products are Mg2Si, MgAl2O4 and Fe for the former whereas are Mg2Si, MgAl2O4 and NiO obtained for the latter. Moreover, the thermal conductivity and relative density of the composite with Ni(NO3)2·6H2O as pore-forming agent are lower than those with Fe(NO3)3·9H2O. The reason of these differences may be the thermite reaction in Fe2O3 and Al system occurred, which improves the wetting property, and therefore higher density composite can be achieved.
Key words: pore-forming agent; SiCp/Al composite; pressureless infiltration; microstructure; thermal conductivity
