In order to study the residual stress of Al2O3 ceramics and kovar alloy after brazing, this article conducted both X-ray diffraction and strain gauges measurement. Using Stress diffractometer and constant strength beam calibration method to examine the x-ray diffraction characteristics of these two materials. And compare measured results and theoretical results. It is shows that the Al2O3 ceramics has two obvious diffraction peaks in 140°~170°, where the diffraction peak at 2θ=153° can reflect the changes of stress more accurately then one at 2θ=146°. For kovar alloy, there is only one diffraction peak at 2θ=149° in range of 140°~170° and it has good linear relationship with stress.

The influence of 60Co gamma-ray irradiation on the chemical compositions and properties of an epoxy encapsulant was investigated. The total irradiation dose varied from 0.1 kGy to 100 kGy with a fixed dose rate of 500 Gy/h. Fourier transform infrared spectra, X-ray photoelectron spectroscopy analysis and discoloration proved the occurrence of oxidation caused by the irradiation. Tg and density remained unchanged owing to the competing effects of irradiation-induced degradation and crosslinking. The tensile strength, impact strength and electrical strength did not decrease distinctly until the irradiation dose reached above 11 kGy. Rubbery coefficient of linear thermal expansion (CTE), relative permittivity and dissipation factor, on the contrary, were more sensitive to the oxidation and increased sharply when the irradiation dose was only 0.1 kGy. Our results suggested that the evolution of CTEs and dielectric properties could affect the long-term application and reliability of the epoxy encapsulant in the irradiative environment.