“…The key elements are those that form volatile species, either directly or by reactions with the atmosphere (Sonntag et al, 2003). The additives typically used to promote the sintering of AlN are alkaline-earth oxides, rareearth oxides, or mixtures of oxides and carbides (Boey et al, 2001;Buhr & Muller, 1993;Hundere & Einarsrud, 1997;Kurokawa et al, 1988;Qiao et al, 2003a;Molisani et al, 2006;Terao et al, 2002;VanDamme et al, 1989;Watari et al, 1999;Wang et al, 2001;Yu et al, 2002). The sintering aids of the CaF 2 -YF 3 system are interesting due to the absence of oxygen and the low liquidus temperatures.…”