(a) Cite three reasons why ferrous alloys are used so extensively. (b) Cite three characteristics of ferrous alloys that limit their utilization.

There are several reasons why ferrous alloys (which are iron-based metals) are extensively used in various applications. Some of these reasons are: 1. Abundance: Iron is the fourth most abundant element in the Earth's crust, making it relatively accessible and inexpensive to extract and process. 2. Variety of Alloys: Ferrous alloys offer a wide range of mechanical and physical properties due to different alloying elements and heat treatments. This range of properties makes them suitable for various applications such as construction, automotive, and manufacturing industries. 3. Excellent mechanical properties: Ferrous alloys typically exhibit high strength, good ductility, and resistance to fatigue. This makes them ideal for use in structures and machinery that experience significant loads and stresses.

Though ferrous alloys have many advantageous properties, there are certain limitations that affect their usage and applications. These limitations include: 1. Corrosion: Ferrous alloys, particularly iron and steel, are prone to rusting when exposed to moisture and oxygen, resulting in a degradation of their mechanical properties. This corrosion can limit the longevity of structures and components made from these materials. 2. Weight: Many ferrous alloys have a high density, making them heavier than other materials such as aluminum or magnesium alloys. This increased weight may limit their use in applications where low weight is essential, like aircraft and certain automotive applications. 3. Limited high-temperature performance: While ferrous alloys exhibit good mechanical properties at room temperature, their strength and ductility can decrease significantly at elevated temperatures. This limit may restrict their usage in applications involving high temperatures, such as in jet engines or high-temperature chemical processes.