GEORGIA INST OF TECH ATLANTA ENGINEERING EXPERIMENT STATION
The objectives of this program are to develop composite materials based on slip-cast fused silica which have a higher degree of rain erosion resistance and ablation resistance than fused silica itself, and to develop a method other than slip casting for fabrication of rebonded fused silica radomes. Task I of this program studies the effects of small additions of SiC and Si3N4 on the ablation and rain erosion resistance of slip-cast fused silica. The best composites were in the range of 10 SiC and 10 Si3N4. Ablation resistance was improved with both additives, but resistance to rain erosion did not show any improvement under the test conditions used. Task II of this program evaluated isostatic pressing as an alternate radome forming method. Radome shapes were pressed however, physical properties of the pressed fused silica powders were less than those of slip-cast items. Work so far indicates that the isostatic pressing process has potential, but that further development is still needed.