I would advise PVD sputtering or PE-CVD, these methods would enable a coating that is bonded to the surface. However, the level of adhesion may not be appropriate for your specific application. What is the purpose of the coating? 

Thanks James N. Barry

Dear Dr. Anaee:

Some set of factors can affect the structure or nature of deposits.

In this sense, a list of them can be taking in account, as follow in a spontaneous order:

i) Vibrations or similar phenomena at electrode of deposit

ii) Low level of tension between electrodes

iii) High current level

iV) Dissociation of liquid of dispersion, at surface of electrode, in which deposition will be formed

v) Barbotine far from a stabilized dispersion

vi) Low level of comminution of powder or very high particle size or very high size of agglomerates

vii) Distance of work between electrodes is very large

viii) Inversion of tension polarity between electrodes

ix) Low level of charge at surface of particle oxides

x) Strong turbulence of barbotine at around position of electrode of deposit

xi) Several item pertinent to the steal surface including passived shell

xii) Electrodes geometry

xii) Selection of the fluid, as an example water undergoes easy dissociation reaching deposit disruption, when particle charge is small and further electric field is necessary.

xiii) High concentration level of barbotine, the fraction of solids is excessive in the fluid

Kind regards

Marcos Nobre

Dear Dr. Anaee:

Please, seems that most usual in English is to use the word slip instead barbotine (French). In brazilian Portuguese can be used the word barbotina (also Spanish); sorry.

In time, I would like to comment that the selection of electrophoretic methods seems be adequated to attain further surface protection, when severe mechanical solicitation can be expected. Also considering the intrinsic high hardness and refractory character that a high thickness deposit can be allow.

In this sense, some changing of the enamel technology can be further considered when hibridized with functional addition of particles of materials with high hardness as zirconia and synthetic corundum (Al2O3.Cr). But, typically limitation of thickness of the deposit emerges due "glass nature".

Kind regards

Marcos Nobre