Study On Preparation And Properties Of Al-Si/Al₂O₃High Temperature Phase Change Heat Storage Materials

Heat storage materials including sensible heat storage material、phase change heatstorage material、chemical reaction heat storage material. The principle of phasechange heat storage is using phase change materials absorb and release heat tostore heat when the phase transition occurs. It has the advantages of high heat storagedensity per unit weight（volume），narrow range in temperature variation around thephase change point for heat absorption and release. Phase change materials,especially high temperature phase change materials have strong corrosion which limittheir application. One of the main directions of preparing a high temperature phasechange material is to make phase change material complex in a common matrix withthe feature of good corrosion resistance.In the paper, a new type metal/ceramic （Al-Si/Al₂O₃）composite heat storagematerial is fabricated successfully by mixing and sintering method. The fabricationtechnology of Al-Si/Al₂O₃composite heat storage material and the effect of thetechnology parameters including raw material percentage, forming pressure, holdingtime, sintering temperature and the time of heat preservation. The effects of additives,the compression speed, mold release pressure and body density uniformity in themolding process on the subsequent sintering process were also researched. Themicrostructure and TG-DSC curve of the composite material were researched by usingmetallurgical microscope and differential scanning calorimeter.The themro-cycling stability of composite heat storage material were Studied by differential scanningcalorimeter.The results showed that the phase of composite material distribute equably,endothermic peak appeared in the DSC curve. The composite material whichcontaining40%of Al-Si alloy have the best heat storage performance. It has phasechange latent heat of69.08J/g, heat-storage density of206.8J/g （ΔT=100℃）,thermal conductivity of79.41W/（m·K）. After300thermal cycling test withrapid heating and cooling, the composite material weight loss rate is about0.97%,phase change latent heat value decreased about4.23%, the performance of compositematerial decreased very low. The material have excellent thermal shock resistance.