镀层厚度对镀钛金刚石/铝复合材料热导率的影响  

Effect of coating thickness on thermal conductivity of Ti-coated diamond/Al composites

作　　者：陈代刚[1] 于家康[1] 于威[1] 袁曼[1] 

机构地区：[1]西北工业大学凝固技术国家重点实验室,西安710072

出　　处：《中国有色金属学报》2013年第3期802-808,共7页The Chinese Journal of Nonferrous Metals

基　　金：国家自然科学基金资助项目(60776019)

摘　　要：通过在金刚石表面镀钛来改善金刚石和铝基体之间的弱界面结合,并用气压浸渗法制备体积分数为60%的镀钛金刚石/铝复合材料。研究镀钛后金刚石颗粒的物相组成、不同镀层厚度和不同颗粒尺寸下复合材料的热导率;用H-J和DEM模型预测复合材料的热导率,并将预测结果与实验值进行对比。结果表明,镀钛后金刚石颗粒的物相由金刚石、碳化钛和钛三相组成;随着镀层厚度的增加,界面传热系数减小,复合材料的热导率减小;颗粒的尺寸越小,这种变化趋势越明显;相对于H-J模型,DEM模型更能准确地预测镀钛金刚石增强的复合材料的热导率;通过计算得出镀钛金刚石/铝复合材料的临界镀层厚度为1.5μm,当超过此临界镀层厚度时,镀层反而不利于复合材料热导率的提高。Titanium coating on diamond surface was adopted to improve the weak interface bonding between diamond and aluminum matrix. The Ti-coated diamond/A1 composites were fabricated by gas pressure infiltration with a 60% volume fraction of diamond. The phase composition of diamond after coating titanium and the thermal conductivity （TC） of Ti-coated diamond/A1 composites under different coating thicknesses and different particle sizes were also studied. The predicted results of the H-J and DEM models were compared with the experimental values. The results show that, the diamond particles are composed of three phases： diamond, TiC and Ti; along with the increase of the coating thickness, interface heat transfer coefficient and TC of composites decrease, the smaller the particle, the more obvious the tendency. Compared with the H-J model, the DEM model gives more accurate predictions for Ti-coated diamond/A1 composites. The critical coating thickness was calculated to be 1.5 prn for diamond/A1 composites. When the coating thickness exceeds this critical value, the coating is detrimental to improving the TC.

关 键 词：镀钛金刚石 铝复合材料 镀层厚度 热导率 界面传热系数 气压浸渗 

分 类 号：TB333[一般工业技术—材料科学与工程]