: The problem of creating reliable materials for the electrodes of open cycle MHD generators is still incompletely resolved. The accumulation of experimental data on the interaction of refractory electrode materials with aggressive flows is one of the pressing problems in seeking the necessary compositions, technology of separation and means of protection against electrode destruction. Carbides and borides of transition metals from groups IV-VI of the periodic system, having high melting points, high hardness, high temperature- strength, wear resistance, high thermal and electrical conductivity, are of considerable practical interest in high temperature technology, in particular when they are used as the electrode materials in MHD equipment. The work studies the behavior of niobium and titanium carbides, and zirconium boride in a flow of air plasma.

The conditions for preparation and several physical properties (microhardness, specific electrical resistance, emission capability, parameters for thermal emission) and also the phase composition of alloys of the WB — LaB6 system (the portion 1–50 mol.% LaB6) were investigated.

A technique has been developed for the preparation of W-BN system alloys with various boron nitride contents.

Investigation has been carried out of the physical properties (specific electrical resistance in the range 293–1273° K, the parameters of the thermal emission and the coefficient of radiation in the range 1200–1950° K, and microhardness) and a study has been made also of the phase composition of the alloys of the W-LaB6 system (from 1 to 50 mol. % LaB6).

A method has been developed for producing experimental specimens of heaters in the form of tubes and rods of NbC.

We have studied the conditions for the preparation of niobium carbide in a hydrogen atmosphere. We have shown that a charge where the carbon black is 97% of the calculated value should be heated at 1700° for one hour.

Conditions for the formation of niobium carbide by the reduction of riobium pentoxide with soot in a hydrogen atmosphere and in a vacuum were investigated. The optimal conditions for obtaining niobium carbide were: heating a charge containing 97% of the calculated quantity of soot at 1700 un. Concent 85% C for one hour; and heating a stoichiometric charge twice at 1700 un. Concent 85% C in vacuum for one hour with intermediate grinding and screen-sizing of the product. The maximum bound carbon content in the resulting carbide samples corresponds to the formula NbC/sub 0.98/. (P.C.H.)