This document presents information on magnesium alloys. It discusses how magnesium alloy AZ63 contains a second phase called Mg17Al12 that can act as a corrosion barrier and protect the alloy. It also mentions that magnesium alloys have traditionally been used in aerospace due to their low density and ability to operate under demanding conditions. Some key properties of magnesium include its silvery white color, low density of 1740 kg/m3, and ability to form mechanically resistant alloys while maintaining good corrosion resistance. The document provides an overview of magnesium alloys and their properties and applications.