光学镜面离子束加工的材料去除效率

Material removal efficiency in ion beam figuring for optical component

分析了离子束加工光学镜面的材料去除效率和不同材料之间的相对去除效率与工艺参数的关系。基于Sigmund溅射理论，建立了表征去除效率的指标一法向去除速率、体积去除速率和溅射产额与束能、束流以及入射角度之间的关系模型。以石英、微晶和K4玻璃等为样件，实验分析了去除效率与工艺参数的关系，验证了模型的正确性。分析结果表明，材料去除效率随束流线性增大，与束能平方根约呈线性关系；随着入射角度先缓慢增大，约在60～80。达到最大值，然后迅速降为0。不同材料之间的相对去除效率与束流无关；与束能的关系较弱，可以忽略；随角度变化较为明显。

The removal efficiency and the relative removal efficiency between two different materials and three performance factors, normal removal rate, volume removal rate and sputtering yield, were analyzed in ion beam figuring process. With the Sigmund sputtering theory, the relation models between three factors and processing parameters, such as ion energy, ion flux and ion incident angle, were established. The experiments with samples of zerodur, SiO2 and K4 glass were carried out to an- alyze these relations and to verify the theoretical models,which indicates that the removal efficiency in- creases with the ion current linearly and shows an approximate proportion to the square root of the ion energy. It also increases with incident angle and climbs the summit at about 60-80^o. The relative re- moval efficiency is independent of ion flux, but has a little effect from beam energy, which can be ignored. However, the effect of angle on the relative removal efficiency is rather obvious.