Method (18, 19, 20, 21) for the quality control of a component (4, 4a, 4b, 4c, 4d, i, j, k), wherein the component (4, 4a, 4b, 4c, 4d, i, j, k) is heated (19) by an energy source (5, 5c, 5d), the intensity of which is periodically modulated (18) at at least one frequency 107 , and wherein the amplitude A and/or the phase φ of a heat wave (81) which is modulated at the same frequency ω and is emitted by the component (4, 4a, 4b, 4c, 4d, i, j, k) is/are recorded (20), wherein the particle sized of the material, from which the component (4, 4a, 4b, 4c, 4d, i, j, k) is constructed, and/or the adhesion properties F of a functional layer (42) applied to the component (4, 4a, 4b, 4c, 4d, i, j, k) are evaluated (21) from the amplitude A and/or from the phase φ. Apparatus (100) for carrying out the method.
