For long time, Sn-Pb solder alloys have been used extensively as the main interconnection materials in the soldering. It is no doubt that Sn-Pb offers many advantages including good electrical conductivity, mechanical properties as well as low melting temperature. However, Pb is very toxic and Pb usage poses risk to human health and environments. Owing to this, the usage of Pb in the electronic industry was banned and restricted by the legislation. These factors accelerate the efforts in finding suitable replacement for solder alloy and thus lead-free solder was introduced. The major problems associated with lead-free solder is the formation of large and brittle intermetallic compound which have given a rise to the reliability issues. Micro alloying with Sb seems to be advantageous in improving the properties of existing lead-free solder alloy. Thus, this paper reviews the influence of Sb addition to the lead-free solder alloy in terms of microstructure formations and thermal properties.

This paper investigates the influence of 1%, 2% and 3% zirconia (ZrO2) nanoparticles to the melting, microstructural and mechanical properties of the Sn58Bi solder. Melting temperatures of 145.11°C, 140.89°C and 143.84°C were attained correspondingly for the 1%, 2% and 3% ZrO2 reinforced Sn58Bi solder. The microstructures especially the spacing between the lamellar structures of the Sn58Bi solder alloy was narrower for 1% ZrO2 added with Sn58Bi solder alloy. The highest and lowest hardness value of 32.28 HV and 27.62 HV was recorded for 1% and 2% ZrO2 additions respectively. Highest shear strength value was noted for the 3% ZrO2 added SnBi/Copper joint with 0.8712 kN, while the lowest value of 0.4380 kN noted for the 1% ZrO2 added SnBi/Copper joint. The presence of small-sized ZrO2 nanoparticles can be seen to be properly dispersed at the solder joint to increase the shear load at maximum joint stress.

Blast furnace and cupola furnace are furnace aggregates used for pig iron and cast iron production. Both furnace aggregates work on very similar principles: they use coke as the fuel, charge goes from the top to down, the gases flow against it, etc. Their construction is very similar (cupola furnace is usually much smaller) and the structures of pig iron and cast iron are very similar too. Small differences between cast iron and pig iron are only in carbon and silicon content. The slags from blast furnace and cupola furnace are very similar in chemical composition, but blast furnace slag has a very widespread use in civil engineering, primarily in road construction, concrete and cement production, and in other industries, but the cupola furnace slag utilization is minimal. The contribution analyzes identical and different properties of both kinds of slags, and attempts to explain the differences in their uses. They are compared by the contribution of the blast furnace slag cooled in water and on air, and cupola furnace slag cooled on air and granulated in water. Their chemical composition, basicity, hydraulicity, melting temperature and surface were compared to explain the differences in their utilization.