Hallse, R. L.
Staff scientist, General Dynamics, Pomona, Calif.
Rizley, J. H.
Section head, Materials Research and Process Engineering, General Dynamics, Pomona, Calif.
Pages: 10 Published: Jan 1965
The mechanical, physical, and electrical properties of fused silica are reviewed and compared with those of other ceramics. Particular attention is directed toward the thermal shock resistance of fused silica as compared to alumina, Pyroceram 9606, and beryllia. Techniques for fabricating specific shapes out of fused silica are discussed and the advantages of slip casting are pointed out. The strength of slip-cast fused silica is analyzed in light of typical missile and aerospace requirements. It appears that for most radome applications the strength of slip-cast fused silica is adequate. A successful method of attachment, always a problem with low expansion ceramics, is presented. The factors affecting the transmission of electomagnetic radiation through dielectrics at microwave frequencies are discussed, and the relative advantages and disadvantages of fused silica radomes are pointed out. Data are presented that show fused silica to have exceptional electrical properties for radome applications. The results of recent rain-erosion tests on slip-cast fused silica are presented. Such variables as surface condition, specimen geometry, and attachment are discussed. It appears that, by the use of proper design, rain erosion need not be a problem with fused silica. An explanation of the somewhat unusual rain erosion characteristics of slip-cast fused silica is included. Applications are cited in which the outstanding thermal shock resistance, stable electrical properties, and exceptional dimensional stability of fused silica are being utilized in aerospace applications.
Paper ID: STP47198S