铝硅合金微胶囊的制备与热学性能研究

Preparation and thermal properties of Al-Si alloy microcapsules

以不同硅含量的铝硅合金微粉为原料,采用加压水蒸气腐蚀结合高温焙烧方法,制备了铝硅合金微胶囊,研究了硅含量和焙烧温度对微胶囊微观结构和热学性能的影响,并探讨了微胶囊壳层的形成机制。结果表明,亚共晶铝硅(Al-10Si)和共晶铝硅(Al-12Si)合金形成Al-Si@Al 2O 3微胶囊的焙烧温度为1100℃;过共晶铝硅(Al-30Si)合金形成Al-Si@Al 2O 3-AlOOH微胶囊焙烧温度为800℃;随着硅含量的增加,铝硅合金原料及所制微胶囊的储热密度均逐渐降低;另外,3种不同硅含量微胶囊的相变潜热保持率均大于65%,经50次热循环后,亚共晶和共晶铝硅合金微胶囊相变潜热保持率大于91%,过共晶铝硅合金微胶囊相变潜热保持率为86.4%。由此可见,采用加压水蒸气腐蚀结合高温焙烧法所制得的亚共晶铝硅(Al-10Si)合金微胶囊相变潜热值高,热循环稳定性好,更适宜作为工业用高温相变储热材料。

In this paper,Al-Si alloy powders with different Si contents were used to prepare Al-Si alloy microcapsules through pressurized water vapor corrosion combined with calcination method.The effects of calcination temperature and Si content on the microstructure and thermal properties of the as-prepared microcapsules were studied,and the formation mechanism of the shell of microcapsules was discussed.The results show that,the calcination temperature of the hypoeutectic(Al-10Si)and eutectic(Al-12Si)Al-Si alloys that form Al-Si@Al 2O 3 microcapsules is 1100℃,while the calcination temperature of the hypereutectic(Al-30Si)Al-Si alloy that forms the Al-Si@Al 2O 3-AlOOH microcapsules is 800℃.The phase change latent heat values of Al-Si alloy and the as-prepared microcapsules decrease with the increase of Si content.Moreover,the retention rates of phase change latent heat of microcapsules with different Si contents are greater than 65%;after 50 thermal cycles,the retention rates of phase change latent heat of the microcapsules made from hypoeutectic and eutectic Al-Si alloys are greater than 91%,while that of the microcapsules made from hypereutectic Al-Si alloy is 86.4%.It can be seen that by applying pressurized water vapor corrosion combined with high-temperature calcination approach,the microcapsules made from the hypoeutectic Al-Si alloy(Al-10Si)are more suitable for the industrial application of the high-temperature phase change heat storage materials,owing to the high latent heat and good thermal cycle stability.