Si含量对Al-xSi合金表面PEO陶瓷层形成过程及性能的影响

Effect of Si content on the formation process and properties of PEO ceramic coating on the surface of Al-xSi alloy

摘要:

研究了Si含量对铸造Al-xSi合金表面PEO陶瓷层形成过程及隔热性能和硬度的影响。采用SEM、XRD和EDS对陶瓷层微观结构和物相进行了分析,并运用自制的隔热温差测量装置和显维维氏硬度仪对其隔热性能及硬度进行了测试。结果表明：在等离子体电解氧化初期,硅原子以及第二相Al₃CuNi都会阻碍微弧放电,抑制铝氧化膜的形成,降低膜层的致密性；随着基体中硅含量的升高,Al-xSi合金内初生硅、共晶硅含量增多,出现硅颗粒的堆积现象,等离子体放电越困难,涂层的生长速率降低,陶瓷层中二氧化硅及含硅杂质的含量随之升高,隔热温度也随之升高,硬度下降。

Abstract:

The influence of Si content on the formation process and properties of PEO ceramic coating on the surface of Al Si alloy was studied. SEM, XRD and EDS were used to analyze the microstructure and phase of the ceramic layer, and the heat insulation performance and the hardness of the were tested by using the thermal insulation temperature measuring device and the 500MVDTM digital display. The results showed that in the early plasma electrolytic oxidation, silicon atom and a second phase Al3CuNi will hinder micro-arc discharge, inhibiting the formation of an aluminum oxide film, reducing the density of the film; with the matrix increased silicon content, primary silicon and eutectic silicon content increases in Al-xSi alloy, the phenomenon that silicon particles stacked appears, the more difficult plasma discharge, the growth rate of the coating is reduced, the content of silicon dioxide and silicon impurities in the ceramic layer will be increased, heat temperature also will increase, hardness decrease .