电沉积Co-W合金薄膜的性能研究(英文)

Characterization of Electrodeposited Co-W Alloy Thin Films

柠檬酸盐存在的酸性镀液中(pH=4.0),通过改变[WO42-]/[Co2+]比值电沉积制备了Co-W合金薄膜。使用XRD对薄膜的微结构和相组成进行了分析,结果表明沉积态时,Co-W合金薄膜具有晶态结构;随着薄膜中Co、W含量的不同,薄膜从富Co的面心立方相向Co+Co7W6+Co3W共存相转变。采用FE-SEM对薄膜表面形貌和组成分析表明:Co-W合金薄膜中Co含量较高,随着镀液中[WO42-]/[Co2+]比值的增加,薄膜中W含量会增加,膜面逐渐变得致密;当镀液中[WO42-]/[Co2+]=0.5时,薄膜中W含量达到最大值,同时膜面上出现大量气孔。通过VSM对薄膜磁性能进行了测试,结果显示Co-W合金薄膜的易磁化轴平行于膜面。

The electrodeposition of the binary Co-W alloy films was investigated with different ratios of [WO42]/[Co2＋] in the citrate electrolyte at pH 4.0. X-ray diffraction （XRD） was employed to study the microstructure and phase composition of Co-W alloy thin films. The results showed that as-deposited Co-W alloy films were of crystalline, which converted from a Co-rich face-centred cubic （fee） phase to Co＋Co7W6＋Co3W coexisting when Co and W contents changed in the films. Compositional and morphological analysis of Co-W alloy films were obtained by the field-emission scanning electron-microscope （FE-SEM） equipped with EDX, indicating that Co-W alloy films were rich in cobalt. Moreover, tungsten contents increased with the ratios of [WO42]/[Co2＋] in solutions. The magnetic properties of Co-W alloy films were characterized using a vibrating sample magnetometer （VSM）. The hysteresis loops suggested that the easily magnetized axis of Co-W alloy thin films was parallel to the surface of the films. A saturation magnetization of 131 A.m2·kg^-1 and a coercivity of 3280 A·m-1 were obtained when the current density was 1.0 A·dm2 and [WO42]/[Co2＋] was 0.15.