Technology of gas-thermal deposition has to be based on precise knowledge of all the physical and chemical processes wherein particles of deposited material take part, beginning from their injection into the high-temperature jet and to the moment they are completely cooled down on the surface to be covered by a coating. This paper presents some results of investigations of heterogeneous jets loaded with powder materials at a gas-flame and plasma deposition of coatings using optical methods of recording various phase parameters, including pulse interferometry with field visualization. Paper includes a German-language abstract.