添加提钒尾渣对膨胀石墨/石蜡复合相变材料稳定性和导电性的影响

以不同膨胀石墨（EG-300、EG-350和EG-400）为支撑材料，石蜡（PW）为相变主材，提钒尾渣（VT）为导电强化剂，采用熔融共混法制备复合相变材料，并对复合材料的稳定性和导电性进行测试分析。结果表明，进行60次热循环，EG/PW复合材料质量损失率小于0.03%，VT/EG/PW复合材料质量损失率小于0.08%，添加VT对材料热稳定性影响较小；直线拟合表明质量损失率与循环次数存在线性关系（R²范围在0.06143~0.85924之间）；EG/PW复合相变材料的电阻率会随成型压力增加而减小，添加微米级VT之后规律一致，仅EG-300/PW电阻率随VT添加量增加而减小，添加量应该控制在2%以内，添加VT可以增强复合材料的导电性能；压力从2 MPa变到8 MPa时，电阻率下降率在49%以下，添加VT后复合材料电阻率下降率变大，添加VT可以使复合材料电阻率的压敏性提高；指数拟合显示复合相变材料电阻率与压力之间的指数相关性较高。

Influence of Vanadium Tailings on the Thermal Stability and Electrical Conductivity of Expanded Graphite/ Paraffin Composite Phase Change Materials

Paraffin （PW） is used as the main phase change material， different expanded graphites（EG-300， EG-350 and EG-400） are used as the framework，and vanadium tailings （VT） are used as electrical conductivity enhancing agents. All composite phase change materials （CPCM） are prepared by melt-blending method， and the thermal stability and electrical conductivity of CPCM are tested and analyzed. The results show that it is found that all the mass loss rate of VT/EG/PW material is below 0.08% after 60 energy storage/release cycles too， and the mass loss rate of EG/PW material is less than 0.03%. Addition of VT has little effect on the thermal stability of the material. Linear fitting shows a linear relationship between the mass loss rate and cycle times（R² between 0.06143 and 0.85924）. The resistivity of the EG/PW composite phase change materials decreases with increasing the pressure，and the law is consistent after adding micron-level TVs， only the resistivity of EG-300/PW decreases as the amount of VT increases. The addition amount should be controlled within 2%. Adding VT can enhance the conductive properties of the composite. When the pressure is changed from 2 MPa to 8 MPa， the resistivity decrease rate is less than 49%. The resistivity decrease rate of the composite material becomes larger， after adding VT. Adding VT can increase the pressure sensitivity of the resistivity of the composite. Exponential fitting shows high exponential correlation between the resistivity and the pressure of CPCM.