1. Explain why Pb-Sn alloys are used for soldering.
2. Refractories used in steel making include silica brick that contain very small levels of alumina (Al2O3). The eutectic temperature in this system is about 1587°C. Silica melts at about 1725°C. Explain what will happen to the load bearing capacity of the bricks if a small amount of alumina gets incorporated into the silica bricks.