The objective of this program is to ;mprove the structura of cerainics by 0 processing. The over-all. temperature range of interesnt is IR-00 to above 3000 F.:n the high portion of the range, 3000 F and above, com,-sitions 0oft pure aluina, plus 0 to 2% additions of HgO were studied between 2822 and 31L80 F, at 1 to 7 hour soaking periods and in atmospheres of hydrogen, helium and vacuunm, This work was reported in the previous Final Report; however, the analysis of remalts is reported herein. Petrogiaphic, x-ray, d.c. cinductivity, electron tranamisgion and elb,.tron probe methods wsre used and the results are reporved, The second tMperature range, 2600-3000 F, was studied utilizing the presintered approach to the prereacted raw materials technique and the results were reported -i n earlier reports. The low range, 1800 to 2600 0 F, was studied usi 1 ng the devitrification approach to the prereacted materials technique. The are a of crystallizationi of cordierite in the I'g0'Al~,0 -SiO system was evaluated as a single glass system. A two-glass system, in wfii~h ong glass devitrifies cordierite and the second supplies the bonding system, was studied. Bonding glass compositions were evaluated in the RO'Al 0 *SiO system, in which the RO members are alkaline earth oxides., Composites WUr madi at 10,'-20 and 30% bonding glass. Processing, structures and properties are reported.