This additive is a brown liquid, by means of which, the precipitation or agglomeration of bath solution can be prevented, resulting in the increase of the Al solubility in the bath to around 120g/l without any precipitates and improving of the Al profile surface quality and reducing the loss of the Al and soda during etching. No specific environment protection requirement for its usage.

1. Bath Composition (For make-up):

BY-C21
NaOH
Water

20-30g/L
35-40g/L
balance

2. Processing Parameters:

Temperature
Time
Free NaOH

40-65℃
1-25min
35-70g/L

3. Bath Maintenance:

(1) Analyze the content of free soda and Al+3 daily. The free soda should be kept in the range of 35-40g/L at make-up bath and increase the soda concentration and temperature properly as the increasing of the Al+3 concentration in the bath. The addition ratio between BY-C21 and solid soda is 1:6.
(2) After addition of this additive, the bath solution is grayish black in color, provided all processing conditions are normal. Upon the bath solution's turning grayish white, it implies insufficiency for the additive content or soda concentration and compensation should be taken in time.
(3) During stop-work, this bath should be kept around 40℃. Or increase the contents of NaOH and additive so that is helpful to prevent the agglomeration in the bath.