Laser optical-acoustic method for estimating of volumetric porosity of aluminum alloy coatings on steel substrate

А laser optical-acoustic method for estimating of the volumetric porosity of coatings obtained by arc surfacing of an aluminum alloy on a steel substrate is proposed and experimentally implemented. The method is based on the laser thermo-optical excitation of probe ultrasonic pulses and the measurement of the spectral power of signals scattered by pores (the so-called structural noise power). А special optical-acoustic transducer with a laser source of ultrasound makes it possible to estimate porosity with one-sided access to the flat surface of a coating; the locality of testing in the coating plane is of about 2—3 mm.