J Mater Sci(2007)42:763-771 contra-rotating at 120 r.P. m. After that polishing was were considered but the most suitable condition was done using a TEXMET platen with a wheel using 1 um found to be as follows: 5 kV ion beam energy 0.4A diamond slurry. Final polishing was carried out with current at 30, 25 and 16 impingement angle for 30 h. colloidal silica. Each section takes 10 min and the After milling the foils were then taken from the io polishing pressure was set to 1n per sample and beam thinner and placed directly into the electron maintained at that level during preparation. The microscope for examination. The analytical electron samples were then finished by washing with water for microscopy was carried out using a Philips EM 400 and 1 min and dried. After preparation of the specimens, CM 20 operated at 120 kV and 200 kv, respectively they were mounted on to an aluminium stub and Both were equipped with an Energy dispersive spec- initially coated with carbon or gold in order to prevent troscopy(EDS)system, and the investigation was charging in the microscope. An Edwards coating conducted using bright field, lattice imaging diffraction system E 306A was used for coating. A conducting and micro diffraction techniques silver paste was used with the carbon-coated samples painted on the edge of the sample connecting it with Thermal diffusivity measurement the stub to improve electrical contact. The surface of the heat-treated samples were examined using Philips Thermal diffusivity measurements were carried out 525 scanning electron microscopes(SEM) operating at using the laser flash method originally described by 20 kV with scanning facility operating with a computer Parker et al. [25]. The thermal diffusivity equipment programme-connected microscope used at UMIST has been previously described by Taylor [ 26] Transmission electron microscopy The specimens used in the measurements were in the form of 10 mm- plates with a thickness of appro Discs of the same diameter as the electron microscope mately 2 mm. The specimens were cut from the specimen holder (3 mm in diameter and 2 mm thick) composite plate by using a slow speed diamond saw. were cut from the heat-treated specimens. The spec- In order to ensure optimum absorption of the laser flash imens were prepared for transmission electron micros- at the sample front surface and maximum emissivity for copy(tEm) by a combination of mechanical polishing monitoring the transient temperature at the opposite and ion beam thinning techniques. The specimens were face of the sample, the both faces of the sample were initially ground on 1200 grit wet Sic abrasive until the coated with a colloidal graphite film. Measurements thickness of the specimen was reduced to -150 m. were performed from 100C up to 1,000C with the Further grinding was carried out until the specimen 100C interval. At least three measurements were thickness was 70 um. The foils were then transferred to taken at each measured temperature and averaged a Gatan ion beam thinner. Several milling conditions value was taken for plotting of the graphs Fig. 1 X-ray diffraction spectrum of as-received terial of bMaS/SiC CN Co: Cordierite B: Barium osumilite S: SiC fibre 8 400 300 8 1001B o"T"Jo""4o""5o""6("6contra-rotating at 120 r.p.m. After that polishing was done using a TEXMET platen with a wheel using 1 lm diamond slurry. Final polishing was carried out with colloidal silica. Each section takes 10 min and the polishing pressure was set to 1 N per sample and maintained at that level during preparation. The samples were then finished by washing with water for 1 min and dried. After preparation of the specimens, they were mounted on to an aluminium stub and initially coated with carbon or gold in order to prevent charging in the microscope. An Edwards coating system E 306A was used for coating. A conducting silver paste was used with the carbon-coated samples painted on the edge of the sample connecting it with the stub to improve electrical contact. The surface of the heat-treated samples were examined using Philips 525 scanning electron microscopes (SEM) operating at 20 kV with scanning facility operating with a computer programme-connected microscope. Transmission electron microscopy Discs of the same diameter as the electron microscope specimen holder (3 mm in diameter and 2 mm thick) were cut from the heat-treated specimens. The spec￾imens were prepared for transmission electron micros￾copy (TEM) by a combination of mechanical polishing and ion beam thinning techniques. The specimens were initially ground on 1200 grit wet SiC abrasive until the thickness of the specimen was reduced to ~150 m. Further grinding was carried out until the specimen thickness was 70 lm. The foils were then transferred to a Gatan ion beam thinner. Several milling conditions were considered but the most suitable condition was found to be as follows; 5 kV ion beam energy 0.4 A current at 30, 25 and 16 impingement angle for 30 h. After milling, the foils were then taken from the ion beam thinner and placed directly into the electron microscope for examination. The analytical electron microscopy was carried out using a Philips EM 400 and CM 20 operated at 120 kV and 200 kV, respectively. Both were equipped with an Energy dispersive spec￾troscopy (EDS) system, and the investigation was conducted using bright field, lattice imaging diffraction and micro diffraction techniques. Thermal diffusivity measurement Thermal diffusivity measurements were carried out using the laser flash method originally described by Parker et al. [25]. The thermal diffusivity equipment used at UMIST has been previously described by Taylor [26]. The specimens used in the measurements were in the form of 10 mm2 plates with a thickness of approxi￾mately 2 mm. The specimens were cut from the composite plate by using a slow speed diamond saw. In order to ensure optimum absorption of the laser flash at the sample front surface and maximum emissivity for monitoring the transient temperature at the opposite face of the sample, the both faces of the sample were coated with a colloidal graphite film. Measurements were performed from 100 C up to 1,000 C with the 100 C interval. At least three measurements were taken at each measured temperature and averaged value was taken for plotting of the graphs. Fig. 1 X-ray diffraction spectrum of as-received material of BMAS/SiC CMC 123 J Mater Sci (2007) 42:763–771 765