A study of the chemical reactions involved in Li-Ca-N system

Abstract The chemical reactions and phases involved in the potential flux system of Li–Ca–N for the growth of bulk GaN crystals have been investigated under varying conditions. It is found that no preferential nitrification of Li or Ca by N 2 in Li–Ca melts at 500 °C. Only the ternary compound LiCaN is identified in the Li–Ca–N system under the present experimental conditions. Static N 2 pressures are found to enhance the formation of LiCaN compared to an N 2 stream. LiCaN forms from two possible pathways: one is a modified metathesis chemical reaction represented by Li 3 N+Ca→LiCaN+2Li, and the other is a combination chemical reaction represented by Li 3 N+Ca 3 N 2 →3LiCaN. The formation of LiCaN by the metathesis reaction is thermodynamically favored over the other pathway. In addition, the formation of LiCaN might benefit from a slightly larger initial amount of Li 3 N compared with Ca or Ca 3 N 2 .