【作者】 王伟；

【导师】 马爱洁； 高伟；

【作者基本信息】 西安工业大学 ， 材料与化工（专业学位）， 2025， 硕士

【摘要】 金属相变材料（PCM）因其储能密度大、相变温度范围宽、循环稳定性好以及导热系数高等优点在现代科技和工业的中高温（500-700℃）热管理领域具有广泛的应用前景。然而,在实际应用中仍面临两大难题:（1）在储能相变过程中熔融态金属的高化学活性易引发氧化与腐蚀,导致设备受损以及相变材料的潜热降低;（2）在封装使用时,金属PCM固液相变会产生显著的体积膨胀（典型金属相变体积变化率为3-8%）易导致封装结构失效。针对以上现状,本研究以Al-12wt%Si合金为储热芯材,采用“双层包覆-牺牲内层”的微胶囊封装策略,在对金属芯材进行封装保护的情况下,制备具有缓冲相变体积膨胀的空腔,制备出带空腔（Void）的CaCO₃/Void/Al-12wt%Si相变微胶囊。再以氧化铝（Al₂O₃）陶瓷为支撑骨架,与相变微胶囊相结合,制备出一种兼具力学性能和热力学性能的中高温陶瓷基复合储能材料。本文的主要工作如下:（1）以Al-12wt%Si合金粉末为储热芯材,采用界面聚合法制备了聚甲基丙烯酸甲酯（PMMA）包覆的Al-12wt%Si/PMMA相变微胶囊。研究不同的工艺参数对相变微胶囊的影响,得出最佳的制备工艺。当Al-12wt%Si合金和甲基丙烯酸甲酯（MMA）的比例为1:1时,以过硫酸铵为引发剂,添加量为MMA质量的1.5%,在50℃下以350 rpm搅拌反应3小时,制备出覆盖率高,表面光滑的微胶囊。（2）基于性能最优的Al-12wt%Si/PMMA微胶囊,在其表面通过自组装工艺覆盖了CaCO₃陶瓷壳层,随后采用“双层包覆-牺牲内层”策略,对CaCO₃/PMMA/Al-12wt%Si相变微胶囊进行热处理,使PMMA层完全分解,制备出具有应力缓冲空腔的CaCO₃/Void/Al-12wt%Si相变微胶囊。研究了微胶囊的最佳制备工艺和热力学性能。结果表明,采用浓度为12 mmol/L的十二苯磺酸钠（SDBS）作为表面活性剂制备CaCO₃陶瓷壳层,热处理温度为400℃,升温速率1℃/min,保温时间1h,得到的CaCO₃/Void/Al-12wt%Si相变微胶囊具有良好的热力学性能,其熔化潜热达到393.8 J/g,过冷度降低为15.2℃,同时在150次热循环后保持热焓值几乎不下降,和经历950℃的热冲击后依旧保持完整。（3）通过混料-冷压-烧结工艺,将带空腔的CaCO₃/Void/Al-12wt%Si微胶囊与Al₂O₃陶瓷材料相结合,制备出块状陶瓷基复合相变储能材料。探究了带空腔相变微胶囊的含量对复合相变储能材料的影响。实验结果表明,带空腔相变微胶囊含量为60 wt%时具有最佳的性能,此时复合相变储能材料的结晶潜热为127.54 J/g,热导率为3.63 W/（m·K）,抗压强度为39.6 MPa,远高于国家耐火砖的使用标准（20 MPa）。此外,该材料在经历300次热循环后,结晶潜热为106.75 J/g,熔化潜热为98.38 J/g。更多还原

【Abstract】 Metallic phase change materials（PCMs）show great potential in thermal management for mid-to-high temperature applications（500–700℃）thanks to their high energy storage density,broad phase change temperature range,good cyclic stability,and high thermal conductivity.However,two major challenges remain in practical applications.First,the high chemical reactivity of molten metals during phase changes can cause oxidation and corrosion,damaging equipment and reducing the PCM’s latent heat.Second,the significant volumetric expansion（typically 3–8%）during the solid-liquid phase change of metal PCMs can lead to encapsulation structure failure.To address these issues,this study uses Al-12wt%Si alloy as the thermal energy storage core material.A"double-layer coating with a sacrificial inner layer"microencapsulation strategy is adopted.This approach not only protects the metal core but also creates a void cavity to buffer the volumetric expansion during phase changes,resulting in CaCO₃/Void/Al-12wt%Si phase change microcapsules.By combining these microcapsules with an alumina（Al₂O₃）ceramic support framework,a ceramic-based composite material for mid-to-high temperature applications is developed,which has both mechanical and thermodynamic properties.The main work of this study is as follows:（1）Using Al-12wt%Si alloy powder as the thermal energy storage core material,Al-12wt%Si/PMMA phase change microcapsules with PMMA coating were prepared via interfacial polymerization.The effects of different process parameters on phase change microcapsules were studied to determine the optimal preparation process.When Al-12wt%Si alloy and methyl methacrylate（MMA）are in a ratio of 1:1,ammonium persulfate as an initiator added at 1.5%of the mass of MMA,and the mixture is stirred at 50℃ and 350 rpm for 3 hours,the microcapsules prepared have high coverage and smooth surfaces.（2）Based)on the optimal Al-12wt%Si/PMMA microcapsules,a CaCO₃ceramic shell layer was coated on their surfaces via self-assembly.Then,using the“double-layer coating-sacrificial inner layer”strategy,the CaCO₃/PMMA/Al-12wt%Si phase change microcapsules were thermally treated to completely decompose the PMMA layer,resulting in CaCO₃/Void/Al-12wt%Si phase change microcapsules with stress-buffering cavities.The optimal preparation process and thermodynamic properties of these microcapsules were investigated.Results showed that using sodium dodecyl benzene sulfonate（SDBS）at 12mmol/L as a surfactant to prepare the CaCO₃ceramic shell layer,with a thermal treatment temperature of 400℃,a heating rate of 1℃/min,and an insulation time of 1 hour,the resulting CaCO₃/Void/Al-12wt%Si phase change microcapsules exhibited excellent thermodynamic properties,such as a melting latent heat of 393.8 J/g and a supercooling of 15.2℃.Their thermal hysteresis remained almost unchanged after 150 thermal cycles,and they maintained integrity after a thermal shock of 950℃.（3）Using a mixing-cold pressing-sintering process,block ceramic-based composite phase change energy storage materials were prepared by combining hollow CaCO₃/Void/Al-12wt%Si microcapsules with Al₂O₃ceramic materials.The effects of the content of hollow phase change microcapsules on the composite phase change energy storage materials were studied.Results showed that when the hollow phase change microcapsules content was 60 wt%,the composite phase change energy storage materials exhibited optimal properties,with a crystallization latent heat of 127.54 J/g,a thermal conductivity of 3.63W/（m·K）,and a compressive strength of 39.6 MPa,all far exceeding the national standard for fire bricks（20 MPa）.After 300 thermal cycles,the materials still had a crystallization latent heat of 106.75 J/g and a melting latent heat of 98.38 J/g.更多还原