Experimental setup. (a) The sample placed in the “RITM-SP” unit for surface alloying. (b) The scheme for vibroacoustic signals recording: 1–a sample; 2–wire waveguide; 3–a receiving plate; 4–a KD-35 accelerometer with a magnet (ViCont, Moscow, Russia); 5–PM-3 preamplifier Izmeritel, Rostov, Russia); 6–VSV-003 amplifier (ViCont, Moscow, Russia); 7–E440 ADC (L-Card, Moscow, Russia); 8–registering computer.