High-temperature friction performances of graphite blocks (GBs) and zinc phosphate impregnated graphite blocks (IGBs) were evaluated under various friction temperatures. The surface of IGB exhibited extremely lower average friction coefficient values, that was 0.007 at 400 °C and 0.008 at 450 °C, in comparison to that of GB (0.13 at 400 °C and 0.16 at 450 °C, respectively). The worn surface of IGB in the high-temperature friction test was smoother and more complete than that of GB. The wear under high temperature and load caused the transformation of zinc pyrophosphate to zinc metaphosphate and the formation of a continuous large-area boundary lubrication layer combined with graphite and metallic element on the wear surface. The superior tribology property of IGB could be attributed to the digestion of iron oxides by tribo-chemical reactions and passivation of the exposed dangling covalent bonds. Specifically, the layered structure generated on the IGB wear interface effectively decreased the adhesive forces and prevented the surface from serious damage.
Huibin Yin,Shiyuan Gao,Chengcheng Liao,Chaomei Li,Zhuodi Cai,Yongjun Xu,Jian Liu
Expanded graphite based composite phase change materials is a good candidate for latent thermal energy storage system, while suffering large volume expansion in the phase changing process. In this work, a self-assembly method is presented to build novel 3D-graphite block, and phase change composite based on the block is prepared via casting way. The new phase change material exhibits large thermal conductivity and low volume expansion. The continuous 3D-graphite network of the carbon skeleton leads to high thermal conductivity of 15.6 W m −1 ·K −1 and volume expansion lower than 1%. The SEM characterization, XRD patterns, impact strength and electrical conductivity results reveal that the 3D block has network interaction and percolating threshold. Then, a new model is proposed to predict the thermal conductivity of new composite. The new phase change material has great thermal energy charging/discharging performance, which has promising application foreground as heat capacitance in thermal energy systems.
危险品化学品经营许可证（带存储）