ALONTM Optical Ceramic is a durable window material for UV, Visible and Mid IR window and dome applications. The mechanical, thermal, and optical properties of ALON products produced commercially by Surmet Corporation have been measured and this new data will be presented. Comparisons to previously measured data will be made.
Optical quality, low scatter ALON having high strength that is nearly double previously reported has been made. Average strength values of 700 MPa at 21°C and 631 MPa at 500°C have been measured for ALON specimens prepared by precision surface finishing techniques. Polished optical domes tested have survived severe thermal shock tests. These strength levels are comparable to those for single crystal sapphire. Strength, thermal conductivity, thermal expansion, refractive index, emissivity and absorption coefficient will be presented. The possible mechanisms for the increased strength will be discussed.
Missile domes made from Sapphire or other ceramic materials must be attached to metallic structures with different Coefficients of Thermal Expansion (CTE's) without blocking aperture or causing optical deformation due to mounting. High speed, high temperature environments are demanding requiring a strong, robust mount while maintaining optical location and figure. Brazing using compliant, CTE matched materials and active braze alloys have been highly successful in solving these problems for missiles. Descriptions of several different design approaches will be discussed and the advantages of each presented.