plating, anodizing, & finishing Q&As since 1989
HF/HFSA chemistry For Aluminium
October 14, 2012
Q. Hello everybody, hi Ted.
Is anybody there who can help me in micromile or details?
I am working as a production instructor in an anodise shop for anodising alloys.
I want to use 4%v to 5%v hydrofluoric acid or hydrofluosilicic acid in bath for aluminium reflecting image surface at room temperature for the first time. So my question is what is this 4%v to 5%v of HF/HFSA? Is it dilute HF/HFSA ? If yes then at that dilute condition is it harmful or dangerous for human at short or long time contact? Means skin burn or irritation etc?
Exactly what chemical reaction occurs by dipping aluminium in HF/HFSA 5%v bath. HF/HFSA bath containing some additives like wetting agent/gum. Is there any toxic or hazardous fume produce during this process? Because I know that concentrated HF/HFSA is a dangerous acid. Is there a temperature increase in this process? I know about metric units so tell me 1 oz/gal is how much gm/litre? Please guide me. Any other guideline on this discussion by anyone is acceptable to me. Thanks in advance. I am waiting for quick response.
- Surat, Gujrat, India
A. Hi Manjol,
Hydrofluoric acid should be considered hazardous at pretty much any concentration and should be handled appropriately. You need to look at the Material Safety Data Sheet (MSDS) and use the engineering controls and Personal Protective Equipment (PPE) described. Never skimp on safety!
5% v/v HF is diluted HF, 1 part acid to 19 parts water, but it normally means 5% of a particular starting concentration (usually either 40% or 60%, you will need to check this out).
1 oz/US gal is about 7.5 g/l (should be close enough for calculating bath make up as there will be a range of concentration.
Aerospace - Yeovil, Somerset, UK