Technique of deposition of coatings by pyrolysis gas composition of precursor (s)

The invention relates to a dispensing nozzle (1) of stream (s) of precursor gas or precursor gas mixture to the surface of a glass substrate (2) in motion, for the gas (s) formed upon contact thereof a coating by a reaction of the pyrolysis type / decomposition. It is equipped with a feeding system comprising a so-called main gas supply of the nozzle body using a common gas supply means for each of the currents to be generated. The diet also includes a supply said auxiliary gas, autonomous from the main power supply and which is intended to locally modify the chemical composition of the main currents generated by said feed.