As the price of Titanium has decreased and become more easily available it has become a sensible choice as a substrate for a Lead Dioxide anode.
Ti is from a group of metals known as Valve metals. The group includes Ta, Nb and Hf. Theses other members may be used as a substrate but they are more expensive and harder to find.
Ti is available on ebay. Search for Titanium sheet or plate or rod. (Search for Titanblech in the German ebay). Grade 1, 2, 3 or 4 are best to use for anodes as the more common 6/4 alloy (6% Al, 4% V) may not be suitable due to the alloying elements. (It may be OK). In the patents etc, when the grade is mentioned it is usually grade one. It is easy to drill and etch. Grade four is difficult to drill and will not etch with HCl, you will need HF acid. Hot Oxalic acid and hot Sulphuric acid can be used to etch Ti. There is some info on Titanium Grades here.

Lead Dioxide plated onto bare Ti will not work because a layer of non-conducting Ti Oxide will always build up between the Ti and the Lead Dioxide. Lead Dioxide oxidizes the Ti. You must have a precoat between the Ti and the Lead Dioxide.

• Industry has used Pt or Pt Oxide as the precoat. This may be too expensive for the home producer. An article, Performance characteristics of a new type of Lead Dioxide coated Titanium Anode, Journal of Applied Electrochemistry. Volume 25, Number 9 / September, 1995, describes an interface coat using Ti, Ta and Pt compounds.

• Another interface layers that has been mentioned is Ebonex, a trade name for Ti4O7. Ebonex can be made from Ti + Hydrogen gas in an oven. See US 2957787, 'Making TiO2 Conductive'. An Ebonex Electrode is described in JOURNAL OF APPLIED ELECTROCHEMISTRY 22 (1992) 200-203.

• A coating of Cobalt Oxide or Manganese Dioxide may also suffice as a precoat between Ti and LD.

• A very cheap interface layer consists of Doped Tin Oxide (SnO2) . Antimony, Molybdenum, Fluorine and Pt (and more) have been used as the dopant. See link below.

• US Patent 4444642 uses MMO as an interface layer. Old pool chlorinator cells, corrosion anodes, or regular MMO coated Ti mesh etc could be used as the substrate. See link below.

Do not use Fluorine additive in Chlorate or Perchlorate cells when using Ti substrate LD Anodes as it may cause cracking of LD and erosion of Ti substrate.

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