Study of the reactions between boron carbonitride and refractory metals and compounds
We investigated the contact interaction between boron carbonitride and tungsten, zirconium carbide, niobium carbide and lanthanum hexaboride in vacuum of 0.133–0.0133 N/m2 within the temperature range of 1000–2100°C.
The presence of contact reaction between the boron carbonitride and tungsten at a temperature above 1800°C was established. The phases formed on the tungsten were identified as W2B,α-WB,β-WB. Furthermore, the presence of free carbon in the reaction products was established.
A contact reaction between boron carbonitride and zirconium and niobium carbide and also lanthanum hexaboride was not observed up to 2100°C.
It was found in the study of the interaction between boron carbonitride and the above-listed materials and also in control tests when it was heated in vacuum that boron carbonitride changes in composition, which is expressed in a color change (the boron carbonitride darkens) and properties (the electrical resistance decreases). A partial decomposition of the component phases of the carbonitride obviously takes place; the free carbon content increases so that the resistance of the material decreases.
KeywordsZirconium Carbide Tungsten Niobium Lanthanum
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