Y. Li et al. /Materials Research bulletin 37(2002)1401-1409 (a) mixed powders (b)reduced powders (c)hot-pfessed body Fig. 2. XRD patterns of the Al2O3/30 vol. BN (a)mixed powders; (b)reduced powders and (c)hot- pressed body(●)aAl2O3;(口)tBN;(■)hBN:(◇) boric acid;(△)urea;(o) Sialon;(V) Al18B4O33L/ / N$7 % ) (/0 #' 3 & & + #' & & & & #' - & &, #' - + #' -+ #' -+ #' &+ #' + #' 1+ #' *@< / *<)< )* * + ! , - .//0 1