Development of Surface Treatment Method for Ultra-Fine Powder Particles for Elastic Emission Machining (EEM)

为了适应不同材料的EEM(弹性发射加工)，需要制备出具有足够表面特性的粉末。并在尺寸恒定的细小粉末颗粒上对任何材料进行包覆。具体来说，我们采用了低温等离子体化学气相沉积技术，避免了粉末颗粒的粘结。(1)1989年，研制了用于粉末表面改性的等离子体化学气相沉积装置。我们确认已经确定了所需的绩效。分析了等离子体CVD腔内气体流动对粉末颗粒运动的影响，实现了对粉末颗粒直径的分级。在所构建的仪器中，可以对粒径在0.03微米和1微米之间的粒子进行分级。(3)我们通常使用SiO_2粒子，但从分散性的角度考虑，我们决定使用胶乳(聚苯乙烯粉末)。胶乳的熔点低于SiO_2，不能在等离子体中包覆。然后，我们对表面处理设备进行了改进，使其能够取出等离子体。然后，将Al_2O_3包覆在乳胶粒子上，并对其进行了电磁兼容实验。发现加工速度与纯Al_2O_3颗粒的加工速度有相同的趋势。

To adapt EEM (Elastic Emission Machining) for various materials, it is necessary to make powder with adequate surface character. And coating any materials on small powder particles which sizes are constant was carried out. Concretely, we use Plasma Chemical Vapor Deposition which process can be done under low temperature so that cohesion of powder particles can be avoided.The following results are obtained.(1) In 1989, Plasma CVD apparatus for powder surface improvement was constructed. And we confirmed that required performance had been established. After that, we made the powder feed instrument and feed efficiency was improved sharply.(2) The powder particles movement by gas flow in the Plasma CVD chamber was analyzed and it was realized that classification of the diameters of powder particles can be done. In the constructed instrument, classification of particle which size is within 0.03 mum and 1 mum can be held.(3) We usually used SiO_2 particle, but from the view point of dispersibility we decided to use Latex (polystyrene powder). The melting point of Latex is lower than SiO_2, so we cannot take coating process in plasma. Then we improved the surface processing apparatus to be able to take out of plasma. After that, we coated Al_2O_3 on Latex particle and EEM experiment with those Latex was carried out. Then we realized that machining velocity has the same tendency with pure Al_2O_3 particle.