Titanium corrosion 1

[deklerk]

Is commercially pure titanuim susceptible of severe general corrosion in a hot (90°C) hydrogen peroxide bearing (0.7M)solution ?
Regards

 

[TVP]

The following information is from ASM HANDBOOK Volume 13 Corrosion:

Titanium alloys are generally highly resistant to oxidizing media and oxidizing acids over a wide range of concentrations and temperatures. Although peroxides are generally oxidizing, titanium alloys can experience general corrosion in aqueous peroxide solutions, depending on concentration, temperaure, and pH. Corrosion rates are minimal in dilute near-neutral hydrogen peroxide solutions, but increase dramatically under alkaline conditions because of the formation of soluble titanium-peroxyl (complex) compounds. However, corrosion is effectively inhibited by small additions of calcium, strontium, or barium ions. Sodium silicate and sodium hexametaphosphate have also been shown to reduce corrosion rates substantially. Significant attack may occur in highly concentrated (90%) H[sub]2[/sub]O[sub]2[/sub] solutions.

The closest data I could find is this: 66 C, pH 1
5% H[sub]2[/sub]O[sub]2[/sub] - corrosion rate = 0.152 mm/yr
5% H[sub]2[/sub]O[sub]2[/sub] + 500 ppm Ca[sup]2+[/sup] - corrosion rate = nil
20% H[sub]2[/sub]O[sub]2[/sub] - corrosion rate = 0.686 mm/yr
20% H[sub]2[/sub]O[sub]2[/sub] + 500 ppm Ca[sup]2+[/sup] - corrosion rate = nil

66 C, pH = 4.3
5% H[sub]2[/sub]O[sub]2[/sub] - corrosion rate = 0.061 mm/yr

70 C, pH 11
0.75 g/L H[sub]2[/sub]O[sub]2[/sub] - corrosion rate = 0.42 mm/yr

60 C
10 g/L H[sub]2[/sub]O[sub]2[/sub] + 20 g/L NaOH - corrosion rate = 55.9 mm/yr

60 C
3.5 g/L H[sub]2[/sub]O[sub]2[/sub] + 10 g/L NaOH + 10 g/L Na[sub]2[/sub]SiO[sub]3[/sub] + 0.5 g/L Na[sub]3[/sub]PO[sub]4[/sub] - corrosion rate = nil

 

[MJCronin]

marco,

Consider:

http://www.titanium.org

http://www.timet.com

and

http://www.corrosion-doctors.org

Good Luck

MJC

 

[BarryMartin]

Pourbaix states that titanium will be corroded in very oxidizing environments such as peroxide although it is dependent on the electrode potential.

 

[ghopkins]

If you already have the material, it looks like it may hold up for awhile. If you are still looking for something that would work in place of titanium, try Teflon-FEP.

see Dupont's website at

http://www.teflon.com

What service application would the Titanium be used in? I may be able to help more depending on what exactly your needs are.

Greg

 

[bilge]

Schweitzer says that titanium is "good" (corrosion less than 20 mils per yesr) in 90% hydrogen peroxide up to a temperature of 200 F.