Laser Cutting of Plasma-Sprayed Refractory Aluminum Oxide Products

The possibility of laser cutting plasma-sprayed refractory products made of aluminum oxide is investigated. An industrial laser complex KS-5VDM1-3 Navigator (VNITEP, Russia), equipped with an LS-3 ytterbium fiber laser with a power of 3 kW, is used in order to develop cutting conditions. It is established that immediately after completion of the plasma spraying process, article material phase composition is a collection of various modifications of aluminum oxide, and subsequent material heating leads to a series of polymorphic transformations accompanied by changes in item material volume and density. The process is complete when all aluminum oxide polymorphic modifications are transferred into the only stable phase α-Al 2 O 3 (corundum). It is shown that laser cutting of plasma-sprayed aluminum oxide products is only possible when transition of all its phase modifications to corundum is completed. In the opposite case, a sharp change in product material volume, due to polymorphic transformations occurring under conditions of a high temperature gradient that occurs during laser cutting, leads to product destruction. A plasma-sprayed article, whose material is entirely the α-modification of aluminum oxide (corundum), withstands high temperature gradients and is easily laser cut without destruction. Cutting technology of plasma-sprayed refractory products made of aluminum oxide is assimilated at the Scientific and Educational Center for the Implementation of Laser Technologies at Vladimir State University.