C3H8O3在ZAlSi12Cu2Mg1微弧氧化膜形成中作用机理的研究

在含Na2SiO38g/L、NaOH 2g/L、Na2WO42g/L、Na2EDTA 2g/L的电解液和正/负向电压取480/130V的条件下,通过改变C3H8O3的含量,对ZAlSi12Cu2Mg1进行微弧氧化处理。研究结果发现,添加C3H8O3可明显地细化电解液中的胶粒,改善微弧氧化膜的致密性和平整性,增加膜层厚度,提高膜层硬度。当C3H8O3的含量由0mL/L增加到10mL/L时,胶粒的平均粒径从10530.6nm几乎线性减小到2615.8nm,膜层氧化物颗粒尺寸变小,致密层所占比例增加,膜层厚度从63μm增加到156μm,膜层硬度提高到894HV;而含量超过10mL/L时,临界起弧正向电压升高至408V。电解液中加入C3H8O3,膜层中除了莫来石相,还出现了α-Al2O3、γ-Al2O3、WO3和SiO2相。

Study on the function mechanism of C3 H8 O3 on ceramic coating formed of ZA1Si12Cu2Mg1 by MAO

In the present study,the micro-arc oxidation coatings of ZAlSi12Cu2Mg1 are obtained at 480V forward voltage,130V reverse voltage and a electrolyte containing 8g/L Na2SiO3,2g/L NaOH,2g/L Na2WO4 and 2g/L Na2EDTA.The influences of content of Glycerin on the arc starting voltage,thicknesses and microhardness of coatings,phase distribution and morphology of coatings were analyzed respectively.The results show that less rough and higher microhardness coatings are formed from an electrolyte with addition of C3H8O3.With the content of C3H8O3 ascending from 0 to 10mL/L,the mean diameter of colloidal particle descends from 10530.6 to 2615.8nm,the thickness of coatings rises gradually from 63 to 156μm,the dimension of the ceramic grains and the proportion of compact layer increase,and the microhardness of coatings reach HV894.But as the content of C3H8O3 excess 10mL/L,arc starting voltage ascends 408V.The result indicates by XRD that the coatings formed from an electrolyte with addition of C3H8O3 were composed of mullite,α-Al2O3,γ-Al2O3,WO3 and SiO2.