Study On Preparation And Properties Of Al/Al₂O₃-MgO-SiO₂ Composite High Temperature Phase Change Thermal Storage Material

In recent years,the contradiction between energy supply and demand has become increasingly prominent with the rapid development of China's industry.It is particularly important to develop and utilize renewable energy technologies.Among many energy storage technologies,phase change heat storage technology is a new and effective technology to alleviate energy supply and demand,and is an important means of heat recovery and reuse system.At present,phase change heat storage materials are widely used in solar energy storage,industrial waste heat recovery,building temperature control and electronic device temperature control and other fields.In this paper,the composite high temperature phase change heat storage material with temperature above 500? was studied experimentally.The composite high temperature phase change heat storage material was prepared by using aluminum as phase change material,ceramic powder mixed with white mud,bauxite and magnesia powder as matrix material,and unidirectional moulding combined with mixed sintering.Phase change materials have excellent heat storage and high temperature resistance.In this paper,the selection of raw materials,composition ratio,forming method and parameters,sintering method and sintering parameters of high temperature phase change heat storage materials are studied.The chemical stability of components of high temperature sintered samples is analyzed by XRD,and the thermal properties of samples are analyzed by DSC.The results show that when the content of aluminium powder is 70%,the contentof white mud is 5%,the content of bauxite is 20%,the content of magnesia powder is5%,the holding time is 20 minutes,the sample mass is 10 g,the pressing pressure is 7MPa,the sintering temperature is 950 ?,and the holding time is 120 minutes,the composite high temperature phase change heat storage material has excellent mechanical properties,thermal physical properties and thermal stability.XRD analysis showed that the samples had good stability before and after sintering and no new phase was formed;metallographic microscopy and SEM microanalysis showed that the materials were evenly distributed and the matrix materials were wrapped up to make the phase change materials have good formability and sintering properties;the latent heat of phase change of the samples with 70% Al content reached 105.66 J/g and the heat storage density was 300.81 J/g.There are two obvious endothermic peaks at 574 and 643 ?.The heat storage density of the material reaches 300.81 J/g.After30 thermal cycles,the weight loss rate of the sample is less than 3%,the phase composition and phase transition temperature are basically unchanged,and the latent heat of phase transformation decreases by 6.72 J/g.Thermal cycle test and thermogravimetric analysis results show that the composite high temperature phase change heat storage material has good thermal stability and excellent heat storage capacity,no deformation and cracking of the sample,and stable physical performance.