石墨烯/纯钛基复合材料的制备及其导电性能的研究

Preparation of graphene/titanium matrix composites and their conductive properties

运用球磨分散结合粉末冶金法成功制备了石墨烯纳米片增强纯钛复合材料.复合材料的制备过程主要包括复合粉末的制备、复合材料的压制成型以及高温烧结3个过程.使用OM、SEM、XRD和拉曼光谱等检测手段对制备的复合材料的组织、物相组成以及石墨烯片的缺陷和层数进行了分析检测.运用显微硬度计和四探针电阻仪对最终烧结成型的纯钛块体及石墨烯增强钛基复合材料的硬度和电阻率进行表征.结果表明:石墨烯片分散在复合材料的组织中,添加石墨烯片能显著影响钛基材料的性能,复合材料的硬度和电导率随石墨烯片含量的添加而增大.当石墨烯的添加量为0.3%(w)时,复合材料的硬度达到最大(429HV),与同样条件烧结的纯钛硬度相比(234HV)提高80%.其导电率是在石墨烯的添加量为0.4%时才达到最大值(432S·m^-1),与同样条件烧结的纯钛的导电率(158S·m^-1)相比提高了1.73倍.文章分析了复合材料的硬度和导电性能增强的原因.

Graphene nanoplatelets (GNPs) reinforced pure titanium matrix (GNPs/Ti) composites were prepared by ball milling dispersion and powder metallurgy methods. The preparation process of GNPs/Ti composites mainly includes the preparation of composite powders, the pressing molding of composite materials, and the high temperature sintering. The microstructure, morphology, composition of facies, defects and layers of GNPs were analyzed and detected by means of optical microscope, scanning electron microscope, X-ray diffractometer (XRD) and Raman spectrum. The hardness and resistivity of the final sintered titanium block and graphene reinforced titanium matrix composites were characterized by microhardness meter and four probe resistor meter. The results show that GNPs do exist in the composites and are stable in the titanium matrix. The addition of graphene microchips makes the hardness and conductivity of the composite material generally larger. When the addition of GNPs was 0.3 wt%, the hardness of the composite material reached maximum (429 HV), which was 80% higher than the hardness of pure titanium sintered under the same conditions (234 HV).Its conductivity reached a maximum (432 S·m^-1) when the addition of GNPs was 0.4 wt %, which was 1.73 times higher than the conductivity (158 S·m^-1) of pure titanium sintered under the same conditions. In this paper, the reasons of hardness and conductivity enhancement of composite materials are analyzed.