What is the cause of loose film when the aluminum profile is black at room temperature? How to deal with it?

The reason:
1 If the degreasing and cleaning are not thorough, the black film formed after blackening will fall off if it is wiped gently;
2 activation is not good;
3 mørkningstid er for lang;
4 dilution ratio is small, the solution content is high, and the nitrite content is high;
5 solution acidity is high; &n aluminum alloy building profile insulation profile bsp;
6 copper replacement is fast, insufficient additives;
7 oil immersion time is short.

Nærme sig:
1 Strengthen pre-treatment, pay attention to degreasing and cleaning;
2 After degreasing, the parts must be fully activated, not only to neutralize the residual lye on the surface, but also to activate the metal surface and increase the bonding strength between the film and the substrate;
3 reduce the blackening time,
4 for strengt at fortynde formuleringsopløsningen i overensstemmelse med formuleringskravene
5 can be neutralized with NaOH;
6 tilsæt additiver
7 extend the oil immersion time.