Patent ID: 8268410

Claim:
A method for coating articles with alternating layers in a coating system, an article to be coated being arranged in at least one reaction chamber, or a reaction chamber being formed with an article to be coated, the method comprising: evacuating at least the coating region of the reaction chamber, leading various process gases sequentially into the coating region, and igniting a pulsed plasma for deposition by means of a source of electromagnetic energy which is operated in a pulsed fashion, as a result of which a layer system with plies of different composition, the layer system having interfaces between individual plies, is deposited on the article, the introduction of the process gases into the reaction chamber being performed by means of a gas changing device, the gas changing device comprising at least one gas mixing point into which there open at least two supply lines, provided with valves, for various precursor gases, and at least one supply line for a further gas, this further gas being mixed in the gas mixing point with respectively one of the gases introduced through one of the valves and being carried away to the reaction chamber by a discharge line, the supply line for a further gas and the discharge line to the reaction chamber being connected in the connection between the two valves, and in each case a bypass line connected to a pumping device being provided in relation to each of the supply lines for various precursor gases, in each case a further valve being connected into the bypass lines, and the process gas mixture being changed by switching the valves in the bypass lines and the valves of the supply lines for various precursor gases such that the valve in the supply line of a precursor gas is closed while simultaneously the valve in the bypass line for this precursor gas is open, and conversely the valve in the supply line of the other precursor gas is open while the valve in the bypass line for this precursor gas is simultaneously closed, a ply of the alternating layer respectively being deposited by means of a pulse series of plasma pulses, the instant at the beginning of a pulse series for depositing a ply of the alternating layer system being set as a function of the switching time of the valves, and there being set between the pulse series for depositing consecutive plies, of different composition, a pause with a duration of at least 0.8×|t advance −t return | and at most 5×|t advance −t return |, t advance denoting the time duration required for the gas to reach from the gas mixing point as far as the reaction chamber, and t return denoting the time duration required to empty the process gas mixture previously located in the reaction chamber.