IN-SITU METHOD FOR SYNCHROTRON INVESTIGATIONS OF MULTILAYER COATINGS IN THE PROCESS OF THERMAL EXPOSURE Russian patent published in 2023 - IPC G01L1/25 G01N23/20 

FIELD: multilayer coatings.

SUBSTANCE: synchrotron studies of multilayer coatings in the process of thermal exposure. The essence of the invention lies in installation of a sample having a multilayer coating on the surface on a heated holder in an air atmosphere; exposing the said sample to effect of monochromatic synchrotron radiation in the X-ray range by method of asymmetric shooting, in the range of angles 2, selected depending on the material of the multilayer coating; heating the said sample at a given rate of temperature increase, providing an exposure time sufficient for phased plotting of an x-ray pattern of a sample with a multilayer coating with use of synchrotron radiation in the heating temperature range determined by the actual conditions of the coating technology, and simultaneous registration and recording of x-ray patterns at steps providing sufficient accuracy of identifying phase transitions and structural changes that occur when the coating is heated in the above temperature range; approximation of the obtained X-ray pattern profiles with the determining characteristics of the reflections of the present phases, such as interplanar distances of the reflections (d) and the width of the reflections at half-height FWHM and identification of all phases of the multilayer coating within the X-ray patterns selected from the entire array of the obtained X-ray patterns after a visual assessment of the temperature of the onset of phase transformations; calculation of the crystal lattice parameter (a) for any phase of the cubic system present in the multilayer coating and the coefficient of thermal expansion (TCEC) for each phase of the exposure temperature at which the sample with the multilayer coating is located at each stage of the heating temperature range; plotting the dependence of the crystal lattice parameter (a) for each phase of the multilayer coating from the exposure temperature at which the sample with the multilayer coating is located at each stage of the heating temperature range, the dependence of the change in the crystal lattice parameter (a) and a graphical definition of the coefficient of thermal expansion (LCTE) from the latter; plotting the dependence of the reflection width at half-height FWHM for the present coating phases on the exposure temperature.

EFFECT: providing the possibility of determining changes in the process of heating the characteristics of multilayer coatings, such as a change in the crystal lattice parameter of each of the coating components separately, the possibility of determining the coefficient of thermal expansion of the coating components and qualitatively determining microstresses.

5 cl, 7 dwg