Electrothermal technology of coating

Abstract

A technique of microparticle acceleration by the shock-compressed gas region (SCGR) of the pulsed gas-plasma flow is used at the Moscow Engineering Physics Institute for the purpose of obtaining coatings out of powder materials by means of electrothermal launchers. As a result, microparticles are accelerated up to high velocities, the required temperature regime of the process being preserved. For SCGR formation, a new launcher structure has been developed. It has an additional cylindrical cavity, which is mounted in the initial part of the barrel behind the discharge gap and is connected with neighboring parts by conic transitions. The large space extension of the so-formed SCGR makes it possible to accelerate microparticles up to very high velocity (up to 2 km/s) and substantially widen the range of their dimensions (up to 50 /spl mu/m) and densities (up to 10/spl times/10/sup 3/ kg/m/sup 3/). Experimental tests and theoretical analysis on the basis of one- and two-dimensional models have shown that a dynamic effect existed which resulted in SCGR additional acceleration in the barrel. That effect increases the microparticle acceleration efficiency.