Method for depositing a coating by DLI-MOCVD with direct recycling of the precursor compound

Process for the deposition on a substrate of a protective coating composed of one or more layers, at least one being a protective layer comprising a transition metal M in the form of at least one protective material selected from the group consisting of a carbide, an alloy and a metal in native or virtually pure form, the deposition process being a process for the chemical vapor deposition of an organometallic compound by direct liquid injection (DLI-MOCVD) which comprises the following steps:

• a) having available, in a feed tank, a mother solution containing:
• a hydrocarbon solvent devoid of oxygen atom,
• said organometallic compound composed of a precursor of bis(arene) type having a decomposition temperature of between 300° C. and 600° C. and comprising the transition metal M, and
• if appropriate, a carbon-incorporation inhibitor;
• b) vaporizing said mother solution in an evaporator and then introducing said vaporized mother solution into a chemical vapor deposition reactor in which said substrate to be covered is found;
• c) depositing the protective layer on said substrate in the chamber of the reactor, the atmosphere of which is at a deposition temperature of between 300° C. and 600° C. under reduced deposition pressure, the deposition of the protective layer on said substrate comprising consumption of the precursor which comprises the production of a gaseous effluent comprising aromatic byproducts of the precursor;
• d) collecting, at an outlet of the reactor, a fraction of the gaseous effluent comprising the unconsumed precursor, the solvent and the aromatic byproducts of the precursor, the collecting step comprising an operation of selective condensation of said fraction of the gaseous effluent so as to condense the unconsumed precursor, the unconsumed solvent and the aromatic byproducts of the precursor, wherein the unconsumed precursor, the unconsumed solvent and the aromatic byproducts of the precursor together form, under standard conditions, a daughter solution;
• and
• e) pouring the daughter solution thus obtained into the feed tank in order to obtain a new mother solution capable of being used in step a).