S. Wannaparhun et al /Applied Surface Science 185(2002)183-196 E(ev) Fig 12. XPS O(Is)spectrum(a)the calculated spectrum of the composite(F: fiber and M: matrix);(b) the as-received composite matrix(alumina). On the other hand, the XPS signal acquired xPS data from alumina, mullite and Nex will be only obtained from the fiber if there is no tel-720 fiber was used to deconvolute the complex matrix on the surface. For both cases above, the XPs XPS spectra acquired from CMC, since this CMC signal will indicate characteristic features of the alu- composed of alumina and Nextel-720 fiber mina and the fiber and detailed XPs deconvolution (alumina mullite) only. procedure has been adopted to differentiate chemistry of the matrix, fiber and the interface based on chemical 3.4.1. The spectra from the as-received materials shifts [50]. Practically, the top surface of the CMC The XPS survey scan of the as-received composite possesses a certain degree of roughness and hence the shown in Fig. 14 reveals a combined feature of the al- XPS signal obtained from the top surface will carry satellites of Al(2s) from the matrix and the Si(2p) the information depending upon the thickness of the signal from the fiber matrix phase at the surface. If the alumina matrix area thickness is less than the depth resolution of 3.4.1.1. XPS Al(2p). The Al(2p) signal from the as- the XPS, then the XPs will contain the signal from received CMC can be divided into two parts: (a)from the region underneath the matrix, 1. e, the fiber an the alumina matrix and(b) from the Nextel-720 fiber. interface In addition, the Al(2p) signal from the fiber can be In order to investigate any chemical alteration in divided into the signal from the aluminosilicate and CMC during fabrication, two sets of XPS spectra were the alumina. a detailed XPS Al(2p) is shown in quired: (a)as-received and(b) calculated spectra Fig. 10b. The deconvoluted spectrum indicates the from the individual composite components. The peaks at 73.6 eV(88.2% area) and 74.2 eV(11.8%matrix (alumina). On the other hand, the XPS signal will be only obtained from the fiber if there is no matrix on the surface. For both cases above, the XPS signal will indicate characteristic features of the alu￾mina and the fiber and detailed XPS deconvolution procedure has been adopted to differentiate chemistry of the matrix, fiber and the interface based on chemical shifts [50]. Practically, the top surface of the CMC possesses a certain degree of roughness and hence the XPS signal obtained from the top surface will carry the information depending upon the thickness of the matrix phase at the surface. If the alumina matrix area thickness is less than the depth resolution of the XPS, then the XPS will contain the signal from the region underneath the matrix, i.e., the fiber and the interface. In order to investigate any chemical alteration in CMC during fabrication, two sets of XPS spectra were acquired: (a) as-received and (b) calculated spectra from the individual composite components. The acquired XPS data from alumina, mullite and Nex￾tel-720 fiber was used to deconvolute the complex XPS spectra acquired from CMC, since this CMC is composed of alumina and Nextel-720 fiber (alumina þ mullite) only. 3.4.1. The spectra from the as-received materials The XPS survey scan of the as-received composite shown in Fig. 14 reveals a combined feature of the Al￾satellites of Al(2s) from the matrix and the Si(2p3 ) signal from the fiber. 3.4.1.1. XPS Al(2p). The Al(2p) signal from the as￾received CMC can be divided into two parts: (a) from the alumina matrix and (b) from the Nextel-720 fiber. In addition, the Al(2p) signal from the fiber can be divided into the signal from the aluminosilicate and the alumina. A detailed XPS Al(2p) is shown in Fig. 10b. The deconvoluted spectrum indicates the peaks at 73.6 eV (88.2% area) and 74.2 eV (11.8% Fig. 12. XPS O(1s) spectrum: (a) the calculated spectrum of the composite (F: fiber and M: matrix); (b) the as-received composite. 192 S. Wannaparhun et al. / Applied Surface Science 185 (2002) 183–196