Method of making nitride and oxide electrodes on a solid electrolyte

A method of forming an oxide film electrode on a surface of a solid electrolyte substrate, comprising the steps of:

• suspending a metallic powder in a liquid having a binder dissolved therein;
• forming a coating of the liquid suspension on the surface of the electrolyte, the liquid and binder being evaporable without substantial carbonization as it is heated past a first elevated temperature;
• heating the coating in a hydrogen atmosphere to a selected second elevated temperature in a range from 800.degree. C. to 1100.degree. C. and higher than the first elevated temperature for converting the coating to a bonded film and for increasing bondability of the film to the electrolyte without the electrolyte losing ion conducting properties;
• subjecting the film in the hydrogen atmosphere to the selected second elevated temperature for a first time period to effect a required degree of bonding of the film to the electrolyte;
• and
• subjecting the film at the expiration of the first time period to an oxygen atmosphere for a second time period effective to convert the bonded film to an oxide film.