الفهرس 
IntouctionOnly 14 pages are availabe for public view
 |  | from | 147 |  |  |
| | | from | 147 | | |
Abstract
The aim of our work is producing fusible solder alloys with better properties for industrial applications (such as lead free solders, fusible alloys for soldering microelectronics and computers) by preparing tin- bismuth alloy at different concentrations then selecting the best tin- bismuth alloy then adding different alloying elements (such as silver or cadmium or selenium) to it to improve its physical properties. To get this aim we do that:- Melt spinning technique was used to prepare tin- bismuth alloys at different concentrations then study and analyze structure, electrical resistivity, melting point, elastic modulus, Vickers hardness number, internal friction and corrosion rate in different chemical solutions of these alloys using different experimental techniques such as (x-ray diffraction to study structure, double bridge method to measure electrical resistivity, dynamic resonance technique to measure elastic modulus, internal friction and Vickers microhardness tester, FM-7, to measure Vickers hardness number). From this study, it’s obvious that:- 1- Tin- bismuth rapidly solidified alloys consist of two phases (body-centered tetragonal tin phase and rhombohedral bismuth phase). 2- The electrical resistivity, internal friction and corrosion rate values of Sn- Bi alloys are increased but the elastic modulus and melting point values are decreased by increasing Bi content in it. 3- The Sn70Bi30 has best physical properties as a soft lead free solder alloy as shown in table (1). Adding silver or cadmium to Sn70Bi30 alloy caused a change in its matrix structural which affects on all measured physical properties. Melting point, pasty range and elastic modulus values of Sn70Bi30 alloy are decreased but electrical resistivity and internal friction values are increased by adding silver or cadmium to it as shown in table (2). Also adding selenium as a rare earth element to Sn70Bi30 alloy caused a change in its matrix structural which affects all measured physical properties. Electrical resistivity and internal friction values of Sn70Bi30 are increased with slightly increase in melting point of Sn70Bi30 but pasty range and elastic modulus values are decreased by adding selenium to it as seen in table (2). From our results:- 1- It can reduce the melting point of Sn70Bi30 alloy to 138 or 121.35C by adding silver or cadmium to it. 2- It can reduce the pasty range of Sn70Bi30 alloy to 6 or 5 C by adding silver or cadmium to it. 3- It can produce alloy, (Sn- Bi- Ag or Sn- Bi- Cd), with best physical properties for industrial applications and be friendly to the environment.