A Study of Thermal Properties of Au25Pd75 Alloy Using X-Ray Diffraction

Resumo

Abstract—The structure and thermal properties of Au₂₅Pd₇₅ alloy were studied using X-ray diffraction (XRD) technique. The change in lattice parameter a(T) was measured as a function of temperature using the Bragg line displacement method. The diffraction data obtained in the temperature range of 308–1158 K was utilized to determine the thermal parameters like the characteristic Debye temperature Θ_D, mean square amplitude of vibration \(\overline {{{u}^{2}}(T)} \), and the coefficient of thermal expansion α(T). The results show that the alloy forms a single phase solid solution having a face centered cubic structure (A1-type) in said temperature range. Further, it is found that the addition of gold to palladium leads to an increase in the value of lattice parameter and reduction in the value of Debye temperature, mean square amplitude of vibration, and the coefficient of thermal expansion. The mean square amplitude of vibration was found to obey the classical Grüneisen relationship, as is seen in the case of most of cubic alloys.