S. Wannaparhun et al /Applied Surface Science 185(2002)183-196 60% mullite and 40% a-Al2O3 by mole percent is ulated based on the Al2O3-SiOz phase diagram, h reflects the volumetric com 3.3.2.XPSS(2p3) In Fig. 1la, the presence of Al(2s),'s second satellite along with Si(2p) spectrum makes this feature very useful for monitoring the surface chemical alteration of the fiber The satellite feature is similar to that of the as-received alumina matrix. The Si(2p) signal is mainly from the aluminosilicate in the fiber. Never theless, the Si(2p)signal could be obtained from the alumina matrix in the composite. Herein, a small contribution of the Si(2p)signal from the alumina matrix is negligible. A deconvoluted peak at 101. 8 eV 525 is obtained (Table 1). The discrepancy in the BE of the deconvoluted peak (101.8 ev)from the literature (102.6eV[5l))is noted. Comparing the surface Si/Al Fig9.Deconvoluted O(ls)XPS spectrum of the as-received: (a) ratio of the as-received fiber with that of the as- umina matrix: (b) mullite (1: aluminum oxide; 2: aluminosili- received alumina matrix, the fiber Si/Al ratio(0.32) B E.(ev) Fig 10. XPS Al(2p) spectrum: (a)the calculated spectrum of the composite(F: fiber and M: matrix);(b)the as-received composit60% mullite and 40% a-Al2O3 by mole percent is calculated based on the Al2O3–SiO2 phase diagram, which reflects the volumetric composition of the fiber. 3.3.2. XPS Si(2p3 ) In Fig. 11a, the presence of Al(2s)’s second satellite along with Si(2p3 ) spectrum makes this feature very useful for monitoring the surface chemical alteration of the fiber. The satellite feature is similar to that of the as-received alumina matrix. The Si(2p3 ) signal is mainly from the aluminosilicate in the fiber. Never￾theless, the Si(2p3 ) signal could be obtained from the alumina matrix in the composite. Herein, a small contribution of the Si(2p3 ) signal from the alumina matrix is negligible. A deconvoluted peak at 101.8 eV is obtained (Table 1). The discrepancy in the BE of the deconvoluted peak (101.8 eV) from the literature (102.6 eV [51]) is noted. Comparing the surface Si/Al ratio of the as-received fiber with that of the as￾received alumina matrix, the fiber Si/Al ratio (0.32) Fig. 9. Deconvoluted O(1s) XPS spectrum of the as-received: (a) alumina matrix; (b) mullite (1: aluminum oxide; 2: aluminosili￾cate). Fig. 10. XPS Al(2p) spectrum: (a) the calculated spectrum of the composite (F: fiber and M: matrix); (b) the as-received composite. 190 S. Wannaparhun et al. / Applied Surface Science 185 (2002) 183–196