膨胀石墨压块的制备及其导热性能研究
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摘要
为探索和优化微波法制备膨胀石墨及石墨压块成型工艺,利用激光粒度仪、扫描电镜对膨胀石墨及其压块的形貌、孔隙结构等微观结构进行表征,并进行正交试验分析研究了微波功率、微波时间、膨胀石墨粒径、压块成型压力、单次膨胀量等因素对压块导热性能的影响。结果表明,微波功率和微波时间对压块导热性能有显著影响,功率过低和时间过短会导致石墨膨胀不充分,而功率过高和时间过长则会导致石墨蠕虫被过度灼烧而断裂,膨胀石墨粒径、压块成型压力、单次膨胀量对压块导热率无显著影响。依据实验和分析,以压块导热系数为目标确定了膨胀石墨压块最优制备条件:微波功率为700 W、微波时间为70 s、膨胀石墨粒径为80～100目、单次膨胀量为6. 0 g、压块成型压力为200 MPa,该条件下压块导热系数达到5. 78 W/(m·K)。
To explore the manufacturing process of expanded graphite compacts,their morphology and structure were characterized using laser particle size analyzer and scanning electron microscopy. The effects of the microwave power,radiant time,the particle size of expanded graphite,the manfacturing pressure of compacting and sample amount on the thermal conductivity properties of the obtained compacts were studied based on the orthogonal test method. The results show that the microwave power and radiant time have significant effects as low microwave power and short radiant time for microwave expansion will lead to insufficient expansion,while as high power and long time will lead to excessive burning and fracture of graphite worm. On the other hand,the size of expanded graphite,the manfacturing pressure of compacting and the sample amount have no significant effect. Based on the experiments and analysis,the optimum preparation conditions of expanded graphite compacts with highest thermal conductivity are as follows: the microwave power of 700 W,the radiant time of 70 s,the diameter of expanded graphite of 80-100 mesh,the sample amount of 6. 0 g,the manfacturing pressure of 200 MPa,therefore resulting in the thermal conductivity of the compact reaches 5. 78 W/( m·K).
To explore the manufacturing process of expanded graphite compacts,their morphology and structure were characterized using laser particle size analyzer and scanning electron microscopy. The effects of the microwave power,radiant time,the particle size of expanded graphite,the manfacturing pressure of compacting and sample amount on the thermal conductivity properties of the obtained compacts were studied based on the orthogonal test method. The results show that the microwave power and radiant time have significant effects as low microwave power and short radiant time for microwave expansion will lead to insufficient expansion,while as high power and long time will lead to excessive burning and fracture of graphite worm. On the other hand,the size of expanded graphite,the manfacturing pressure of compacting and the sample amount have no significant effect. Based on the experiments and analysis,the optimum preparation conditions of expanded graphite compacts with highest thermal conductivity are as follows: the microwave power of 700 W,the radiant time of 70 s,the diameter of expanded graphite of 80-100 mesh,the sample amount of 6. 0 g,the manfacturing pressure of 200 MPa,therefore resulting in the thermal conductivity of the compact reaches 5. 78 W/( m·K).
引文
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[2]罗立群,刘斌,安峰文.膨胀石墨孔隙结构及表征方法研究进展[J].化工进展,2017,36(2):611-617.
[3]Sari A,Karaipekli A.Thermal conductivity and latent heat thermal energy storage characteristics of paraffin[J].Applied Thermal Engineering,2007,27:1271-1277.
[4]Kim K J,Montoya B,Razani A,et al.Metal hydride compacts of improved thermal conductivity[J].International Journal of Hydrogen Energy,2001,26(6):609-613.
[5]Chaise A,De Rango P,Marty P,et al.Enhancement of hydrogen sorption in magnesium hydride using expanded natural graphite[J].International Journal of Hydrogen Energy,2009,34(20):8589-8596.
[6]田波,金哲权,王丽伟,等.吸附剂基质膨胀石墨的渗透率与导热系数研究[J].工程热物理学报,2011,32(10):1722-1726.
[7]路阳,彭国伟,王智平,等.膨胀石墨的制备和影响其膨胀体积的因[J].材料导报,2011,25(13):20-23.
[8]徐珊,曹宝月,牛成吉.无硫膨胀石墨的制备及性能表征[J].硅酸盐通报,2017,36(3):1020-1024.
[9]刘国钦,赖奇,李玉峰.石墨粒度对膨胀石墨孔隙结构的影响[J].四川大学学报(自然科学版),2007(1):147-150.
[10]李月峰,张东.膨胀石墨/Li Cl-NaCl复合相变材料导热系数各向异性[J].功能材料,2013(16):122-128.