Electrical and Thermal Characteristics of Pb-Free Sn-Zn Alloys for an AC-Low Voltage Fuse Element

Abstract

The temperature dependence of specific resistivity and thermal conductivity for some Sn-Zn alloys was measured to use their values in electrical and thermal calculations on the basis of Ohm's and Fourier's laws, in order to obtain the temperature-distribution in lead-free fuse elements of electric power line. The interaction between microstructures and their properties was also investigated in Sn-Zn alloys. Specific resistivity and thermal conductivity could be estimated as a function of temperature and alloy composition in the compositional ranges classified from the standpoint of continuity or non-continuity of constituent phases such as primary Zn, Sn-solid solution and eutectic in microstructures of Sn-1 to 100Zn alloys. In the proposed estimations, not only volume fraction of Zn and Sn-solid solution phases but morphologies of both phases were considered in Sn-Zn alloys.

Thermal Expansion, Electrical Resistivity, and Spreading Area of Sn-Zn-In Alloys

“…In general, regardless of differences between various sources, at 298 K, electrical resistivity of pure Sn (11.5-14 lX/cm) (Ref 11,16,17) is higher than the electrical resistivity of pure Zn (5-8 lX/cm) (Ref 11, 16). For this reason, one could assume that the electrical resistivity should decrease with the increasing concentration of the component of lower resistivity, as was shown by Matsugi et al (Ref 11).…”

Control of Electrical and Thermal Properties by 8 vol% Al₂O₃ Distribution States in Zn–50Sn for AC-Low Voltage Fuses

“…1. Zn50Sn microstructure shows the continuity for constituent phases of both primary Zn and eutectic, 15) as described in section 3. Fig.…”

“…The construction of a ZnSn sample, copper heating rod with a cartridge heater and cooling plate and detail procedure were early reported for measurement of the heat conduction. 15) The specific heat (c p ) was measured from 293 K to about 470 K at the rate of 2 K/min, using samples with the diameter of 5 mm and thickness of 2 mm in a nitrogen stream, by the differential scanning calorimetry. Density (μ) measurement using a high density liquid was performed at various temperatures in the range of 293360 K by Archimedes' method.…”

“…Q and the governing equation for boundary mesh points such as the fuse element/ connector, were described in the early report. 15) The finite difference method, FDM, was used to solve the above equations for voltage and temperature as a function of time and position.…”

“…It is considered that electrical and thermal conductivity of SnZn eutectic system alloys are difficult to be estimated using Maxwell 12) and Landauer 13) models, because those properties are directly influenced by morphology of each phase in them as described in Fan's model. 14) Also in our proposed estimations, 15) not only volume fraction of pure Zn and Sn-solid solution containing Zn of less than 1 mass% 16) but morphologies of both phases were considered in SnZn alloys, which led to excellent estimation for their electrical and thermal properties as the function of the composition and temperature. 15) For instance, both primary Zn and eutectic were observed as the continuous phases in Sn50Zn alloy, 15) which led to the same microstructural consideration between both Sn50Zn and Zn50Sn alloys with same continuous phases and their amount, according to the compositional ranges classified from the standpoint of continuity or non-continuity of constituent phases.…”