| 摘要 |
PURPOSE:To simply and effectively remove the scale formed on the surface of excellently activated surface of Ti and V group metals and oxygen rich layer of its lower part, by dipping the above metals in the solution of nitric and fluoric acid and applying ultrasonic waves. CONSTITUTION:Scale formed on activated surface of metal of Ti group, such as Ti, Zr, Ta etc. and V group, is removed by the following method. That is, the above metal materials to be treated are dipped in the solution of nitric acid and fluoric acid composed of 46% fluoric acid (1-10vol%)+61% nitric acid (3-30 vol%)+water (the remainder) and also, ultrasonic waves are applied. On this occasion, the ultrasonic waves are applied directly on the metal materials or form the bottom part of pickling vessel. Further, frequency of the ultrasonic waves to be used is set up 15KHz or more and amplitude is set up within the range of 1-100mu respectively. |
