H2O2 corrosion protection
H2O2 corrosion protection
(OP)
Have application for an electric motor being washed down with 30% hydrogen peroxide. Need shaft material that will withstand H2O2. Shaft must be magnetic. Present shaft material is A311 steel. Need similar mechanical properties. I could also plate current shaft with ?? (motor body is aluminum)





RE: H2O2 corrosion protection
Let's see what Kenvlach says.
RE: H2O2 corrosion protection
Checked some online chemical resistance selectors for materials resistant to 30% H2O2:
http://www.coleparmer.com/techinfo/ChemComp.asp
http://www.us.piping.georgefischer.com/external/chemica...
http://www.astrocosmos.com/pdf/chart.pdf
http://www.titanmf.com/
Results: plastics like PTFE, non-magnetic metals tantalum, zirconium, niobium, titanium and the high nickel alloys.
A survey of half a dozen corrosion books was similarly fruitless: non-magnetic alloys and high Ni- and Si-cast irons.
For general resistance to peroxide in neutral or alkaline solutions: austenitic SS is Normally Excellent, Ni-Resist cast iron is Good to Excellent, and mild & low alloy steel are Good – Suitable when superior alternatives are uneconomical. – Perry’s Chemical Engineers’ Handbook, 6th & 7th Edns.
Specific resistance to 30% hydrogen peroxide: steel has a corrosion rate > 0.050 inch/year at room temperature and above. 12% Cr, 17% Cr and 316 SS’s have corrosion rates in the range 0.002 to 0.020 inch/year at 225oF for H2O2 concentrations to 50%. Nickel corrodes 0.002 to 0.020 inch/year for 100% H2O2 at room T. -- Perry’s, 6th Edn., pp. 23-29 to 23-30.
I would recommend the 400 series SS’s listed in the first paragraph. However, depending upon the A311 grade, the ferritic SS’s even in cold-drawn condition may not meet YS requirements. The martensitic SS’s in Q + T condition should exceed A311 mechanical requirements.
Cr plating (over duplex Ni, of course) of the existing alloy should also work, but would require good rinsing after each cleaning. [Actually, good rinsing should be required in any case.]
So, all things considered, end up in agreement with Metalguy’s answer.
Ken
RE: H2O2 corrosion protection
A water rinse would definitely be required after a peroxide rinse if people are going to be handling this equipment- 30% peroxide causes painful burns to skin- I've had more than a few of these in my lifetime...