An electrochemical method has been developed for production of nanocrystalline tungsten bronzes having a hexagonal structure in polytungstate melts. The necessary electrolysis parameters have been determined for making tungsten oxide bronzes having nanocrystalline needle structures with needles of less than 100 nm in thickness.

It has been established that there are two types of nanocrystalline needles, namely, with a sharp tip and in the form of round rods.

Both nonoriented and oriented (all the nanocrystalline needles have the <0001> orientation) deposits can be obtained.

Nanocrystalline coatings were deposited on metal substrates.

Nanocrystalline tungsten oxide bronzes possess such valuable properties as high corrosionresistance; different nature of electrical conduction, which depends on bronze composition; selectivity to certain types of cations in aqueous solutions; a wide range of color change; and a high catalytic activity.

ADVANTAGES

• No complicated equipment required.

• Time for obtaining nanocrystalline deposits is fractions of a second, which is considerably less as compared to the hours-long processes of other known methods.

Nanocrystalline coatings on metal substrates: а) a flm on a platinum foil; б) a 10-micron layer of bronze on a tungsten plate. Each microcrystal is an oriented nanocrystalline structure.

Two types of nanocrystalline needles:

 a) with a sharp tip;

б) in the form of round rods.