PREPARATION OF WHISKER PENETRATED CERAMICS BY INTERNAL PRECIPITATION OF HOLLANDITE WITHIN A TIELITE MATRIX

Composite ceramics consisting of tielite (Al2TiO5) as the prevailing p hase and potassium hollandite (K2Al2Ti6O16) have been prepared by inte rnal precipitation from amorphous solids having the appropriate compos itions. The formation of the two crystalline phases from a starting ma terial made via a sol-gel process, through reaction sintering, or thro ugh a glass ceramic process has been studied by X-ray diffraction, Al- 27 MAS NMR spectroscopy, DTA-TG and SEM-EDX. It has been shown that th e hollandite phase crystallises as whiskers within the tielite matrix. The approach reported presents an alternative route for the productio n of whisker reinforced materials.