(US4618404-A)      Halogen is generated in a process in which aq. halide is electrolysed in a cell which includes a cathode with an inert metal substrate. The cathode also has an external or superficial coating consisting of an external or superficial material comprising an inert electroconductive Pt gp metal ceramic and an intermediate coating or interlay comprising an inert metal matrix contg. dispersed particles of ceramic which is compatible with the coating.    Pref. the precoating contains particles of valve metal oxide and the matrix is Fe, Ni, Ag, Cu, Co or Cr(alloy).    ADVANTAGE -   High stability is obtd. (7pp)r    (US4648946-A)      An inert metal substrate is coated with an adherent electrocatalytic ceramic material by initially forming an anchoring precoating of ceramic particles dispersed in an inert metallic matrix. The ceramic is compatible with the ceramic of the coating layer and the precoating is formed by galvanic electrodeposition. The matrix metal and particles from the plating both contain ions of the matrix metal and the ceramic material particles are held in suspension.    The precoating is coated with a precursor(s) of the electrocatalytic ceramic, in the form of a soln. or dispersion in a solvent. The solvent is removed and heat applied to decompose the precursor(s).    Pref. metal matrices for the precoating include Fe or Ni. Pref. ceramics for the precoating include Ti-, or Zr-oxide. Pref. electrocatalytic ceramics include Rn- or Ir oxide.    USE/ADVANTAGE -   Alkali metal halide electrolysis electrode, which has stable characteristic is obtd. (7pp)g    (US4668370-A)      Electrode for use in chemical reactions, pref. for electrolysis of metal halides, partic. NaCl, comprises an electrically conductive inert metal substrate and electrocatalytic coating. The coating comprises an anchoring pre-coating on to at least part of the surface of the substrate, including particles of ceramic, i.e. oxide or mixed oxide of e.g. Ti, Zr, dispersed in inert metal matrix; ceramic superficial coating consisting of electrocatalytic ceramic, i.e. oxide or mixed oxide of e.g. Ru, Pt, Co. The precoating ceramic is compatible or isomorphous with the superficial coating ceramic. Precoating is formed by electrodeposition from a plating bath contg. metal ions and ceramic particles.. Soln. contg. precursor cpds. of electrocatalytic ceramic is applied, solvent is removed, and electrode is heated to convert precursor into ceramic.    ADVANTAGE -   Stable, durable and efficient, reducing energy requirements.