The observation by hrtem indicated that the size of particles coated with ultrasonic radiation at room temperature in alkaline formaldehyde bath was about 50 ~ 60nm . the originally granular form of the nano - al2o3 particles has changed into spheral - like shape . the x - ray analysis showed that the plate was the alloy of co - p 对镀覆后镀液成分的分析表明，反应自发停止的原因是主要由于镀液ph值过低，不能提供反应所需要的足够oh ~ - ，同时也使甲醛还原能力下降所致。
