Reliability Level of Pb-Sb-Cu Alloy Electrical Resistance Dependence on Its Melting Temperature and Copper Input Concentration

Abstract

This paper assesses the reliability level of Pb-Sb-Cu alloy electrical resistance dependence on its melting temperature and copper input concentration. The alloy was cast by pouring a stirred mixture of heated Pb-Sb alloy and powdered copper into a sand mould and then furnace cooled. Results of electrical test carried out indicate that the electrical resistance of the Pb-Sb-Cu alloy decreases with increase in the melting temperature of the Pb-Sb-Cu alloy. This invariably implied decrease in the electrical resistivity of the alloy. Increased copper addition (0.99-8.26 wt%) to the base alloy (Pb-Sb) also correspondingly decreased the electrical resistance. The experimental results were complement by results generated using a derived model. The validity of the two-factorial derived model expressed as: ξ = - 0.1248ɤ - 0.0398ϑ + 66.615 was rooted on the expression ξ - 66.615 = - 0.1248ɤ - 0.0398ϑ where both sides of the expression are correspondingly approximately equal. Statistical analysis of the experiment, derived model & regression model-predicted results shows that the standard errors incurred in predicting the Pb-Sb-Cu alloy electrical resistance for each value of the melting temperature and copper input were 0.1247, 0.1722 & 3.517 x 10-5 % and 0.4276, 0.1797 & 0.3593 % respectively. Evaluations indicate that Pb-Sb-Cu alloy electrical resistance per unit rise in the melting temperature and copper mass-input as obtained from experiment, derived model & regression model-predicted results were 0.2507, 0.2309 & 0.2496 Ω /°C and 0.094, 0.0866 & 0.0936 Ω / g respectively. Deviational analysis indicated that the maximum deviation of derived model-predicted electrical resistance from the experimental results was less than 3%. This translated into over 97% operational confidence and reliability level for the derived model and over 0.97 reliability coefficient for the Pb-Sb-Cu alloy electrical resistance dependence on the alloy melting temperature and copper input concentration.