Apparatus and method for thermal spraying

The invention relates to an apparatus and a method for producing a sprayed layer on the surface of a substrate, wherein an admixture material which may have started to melt or is molten, is guided onto the surface of the substrate to be coated using a gas or gas mixture, as well as a relevant installation for producing the sprayed layer by means of a thermal spraying method, wherein the installation comprises means for supplying the admixture material or the gas or gas mixture. According to the invention, at least one feature of the thermal spraying process which influences the quality of the sprayed layer and which is responsible for the formation of the layer and its properties, is recorded, evaluated and assessed, checked, monitored and/or regulated. Both analogue and digital spectroscopic arrangements can be used as optical emission spectroscopic arrangements. The recording, evaluation and assessment, checking and/or monitoring using the optical emission spectroscopic arrangement can advantageously be used for online regulation and if necessary, also for optimising one or a plurality of parameters responsible for the formation of the layer and its properties.