Oxygen plasma immersion ion implantation （PIII） has been conducted on AZ31B magnesium alloy using different bias voltages. The modified layer is mainly composed of MgO and some MgAl2O4. Results form Rutherford backscattering spectrometry （RBS） and X-ray photoelectron spectroscopy （XPS） indicate that the bias voltage has a significant impact on the structure of the films. The oxygen implant fluences and the thickness of the implanted layer increase with higher bias voltages. A high bias voltage such as 60 kV leads to an unexpected increments in the oxygen-rich layer＇s thickness compared to those of the samples implanted at 20 kV and 40 kV. The hardness is hardly enhanced by oxygen PIII. The corrosion resistance of magnesium alloy may be improved by a proper implantation voltage.
模具表面改性日益受到人们重视。本文采用二维Particle-in-cell/Monte Carlo Collision模型对等离子体浸没离子注入处理凹模型腔内表面的鞘层动力学及均匀性进行了研究。考察了电压脉宽对鞘层中电势分布、离子的运动状态以及型腔内表面离子注入剂量、能量和角度的空间分布的影响。结果表明随着电压脉宽的增加,凹模型腔内表面的注入剂量不均匀性增加,同时注入到内表面的高能离子数目也增加。脉冲宽度变化对注入角度影响不大,离子以接近垂直的入射角度注入到型腔底部,而在侧壁上离子注入角度接近45°。当脉冲宽度较大时,发现少部分注入到侧壁上的离子以一定角度从下往上注入到样品表面,这是由于碰撞效应造成的。从能量和剂量的角度,存在一个合适的脉冲宽度,过大的脉宽会引起剂量不均匀性增加,同时离子注入能量也会下降。
