Electrodes of improved service life

A method of preparing an electrode from a substrate metal, which method initially comprises providing a roughened surface by one or more steps of:

• (a) intergranular etching of said substrate metal, which etching provides three-dimensional grains with deep grain boundaries;
• or
• (b) grit blasting of the metal substrate surface with sharp grit to provide a three-dimensional surface;
• with the resulting roughened surface having a profilometer-measured average surface roughness of at least about 250 microinches and an average surface peaks per inch of at least about 40, with said peaks per inch being basis an upper threshold limit of 400 microinches and a lower threshold limit of 300 microinches;
• there thus being subsequently established after either of steps (a) and (b), a ceramic oxide barrier layer on said roughened surface, which barrier layer is provided by one or more steps of:
• (1) heating said roughened surface in an oxygen-containing atmosphere to an elevated temperature in excess of about 450.degree. C. for a time of at least about 15 minutes;
• or
• (2) applying a metal oxide precursor substituent, with or without doping agent, to said roughened surface, said metal oxide precursor substituent providing a metal oxide on heating, followed by thermally treating said substituent at an elevated temperature sufficient to convert metal oxide precursor to metal oxide;
• or
• (3) establishing on said roughened surface a suboxide layer by chemical vapor deposition of a volatile starting material, with or without doping compounds, which is transported via an inert gas carrier to the surface that is heated to a temperature of at least about 250.degree. C.;
• or
• (4) melt spraying ceramic oxide particles onto said roughened surface;
• with there being maintained for said barrier-layer-containing surface said profilometer-measured average surface roughness of at least about 250 microinches and an average surface peaks per inch of at least about 40, the resulting barrier-layer-containing surface being subsequently treated by:
• applying to said barrier-layer-containing surface an electrocatalytic coating, with said method of preparing said electrode.