Experimental study on the cycling stability and corrosive property of Al-Si alloys as phase change materials in high-temperature heat storage

Cycling stability and corrosive property of Al-Si alloys with different silicon mass ratios are experimentally investigated for high-temperature latent heat storage purpose, respectively. Melting temperatures, latent heat, thermal diffusivities of Al-Si alloys after 0, 50 and 100 melting-solidification cycles are measured and their thermal conductivities are calculated. Microstructures of Al-Si alloys after 0, 50 and 100 melting-solidification cycles are observed and the relations between thermophysical parameters and microstructures are discussed. Six kinds of common engineering ceramics are adopted to examine the corrosive property of molten Al-Si alloys. The microstructures and element distributions at the interfaces are detected. It is concluded that the microstructures of Al-Si alloys all changes after cycles; the melting temperatures of Al-Si alloys remain relatively stable after cycles, but the variation of latent heat is only found small for AlSi12 alloy and AlSi20 alloy; due to the microstructure variation, the heat transfer performance of Al-Si alloys changes significantly after cycles except AlSi12 alloy; Al2O3 ceramics and AIN ceramics show excellent corrosion resistance in molten Al-Si alloys; the corrosion resistance of SiC ceramics increases with the silicon mass ratio of Al-Si alloys; corrosion exists between Si3N4/BN/ZrO2 and Al-Si alloys, which however remains to be studied further.