CERAMICS INTERNATIONAL, cilt.39, sa.8, ss.8589-8595, 2013 (SCI-Expanded)
Effect of potassium carbonate addition on the carbothermic formation of hexagonal boron nitride (hBN) was investigated by keeping the K2CO3 added B2O3+C mixtures in nitrogen atmosphere at 1400 degrees C for 40-160 min. K2CO3 amount was varied in the range of 10-60 wt% of the B2O3+C mixture. Products were subjected to XRD and quantitative analyses, SEM and TEM observations, and particle size measurement. Amount of hBN increased considerably with K2CO3 addition; also particle size and crystallinity improved. Catalytic role of K2CO3 was suggested as forming a potassium borate melt in which hBN particles form, in addition to carbothermic formation reaction. Effect of K2CO3 on increasing the hBN amount decreased when it was used over 40%. This was attributed to the rapid evaporation of the formed potassium borate liquid. (C) 2013 Elsevier Ltd and Techna Group S.r.l. All rights reserved.