Thermodynamic modelling of wetting in a B_4C/Ni-Cr-Si system

摘要

Wetting of ceramics by liquid metals is of significant importance in many processes. In this paper, via a thermodynamic modelling of the reactions at a ceramic-metal interface, the wetting behaviour of B_4C was studied with a series of Ni-Cr-Si alloys. The thermodynamic calculations showed that the Ni-Cr-Si alloys with Ni/Cr ratio of 3.4 would react with and wet B_4C ceramics at 1220 °C under vacuum conditions. Experimental verification using the sessile-drop method was performed to confirm the validity of the calculations and the assumptions made in the wetting model. In the situation where the growth rate of the reaction product was not greater than the spreading rate of the liquid, good agreement was found between the theoretical calculations and experimental data. It was also revealed that the increase in Si content in the alloys plays a major role in the improvement of wetting of B_4C by Ni-Cr-Si alloys.