Nanoparticles fabrication in high-enthalpy plasma flow and covering them on a surface

Abstract

The paper describes a new plasma method for applying nanostructured coatings from various chemicalelements and compounds. A specially designed pulsed source of high-enthalpy plasma flow containingchemical elements from which the coating is formed is used as a tool – a disk magnetohydrodynamicaccelerator (MHD accelerator). A mixture of an inert transport gas and gaseous precursors is suppliedto the accelerator inlet through a supersonic nozzle. In the channel of the MHD accelerator, a volumedischarge is initiated in a transverse magnetic field, and the plasma flow acquires a velocity of severalkm/s. The flow generated by the accelerator flows into a vacuum volume and, expanding, cools down,which leads to the chemical transformation of precursors and the condensation of target products inthe form of nanosized particles. The particles move at a paccelerated flow velocity, collide with thetreated surface and form a nanostructured coating on it. An amorphous smooth coating is formed ona substrate installed in the zone closest to the accelerator, where condensation has not yet occurred.The plasma flow pulse time is 48 ms, the coating growth rate is about 3 mkm/s. The main purposeof the work was to demonstrate the possibility of applying nanoparticles to the surface with highadhesion and productivity. A new solution to the problem of synthesizing nanoparticles in a supersonicexpanding jet and applying a structured coating was proposed.