Q1: Which of the following is the most suitable abrasive for grinding high tensile strength materials ?

ANS:C - Aluminium oxide

Aluminum oxide, also known as alumina, is a widely used abrasive material in various grinding and abrasive applications. Here's an explanation of aluminum oxide:

1. Composition: Aluminum oxide (Al₂O₃) is a chemical compound composed of aluminum and oxygen. It occurs naturally as the mineral corundum, but it is also produced synthetically for industrial purposes.
2. Hardness: Aluminum oxide is known for its exceptional hardness, making it suitable for grinding and abrasive applications. It has a Mohs hardness of 9, which is just below that of diamond, making it one of the hardest materials available for abrasion.
3. Abrasive Properties: Aluminum oxide grains are often used in grinding wheels, sandpaper, and other abrasive tools. These grains have sharp edges and are capable of efficiently cutting and removing material from workpieces during grinding and finishing processes.
4. Versatility: Aluminum oxide is versatile and can be used for grinding a wide range of materials, including metals, ceramics, plastics, and composites. It is effective for both ferrous and non-ferrous materials, making it a popular choice in various industries.
5. Types: Aluminum oxide abrasives come in various forms, including fused aluminum oxide, which is produced by melting bauxite in an electric arc furnace, and sintered aluminum oxide, which is formed by heating aluminum hydroxide. These different forms offer variations in abrasive properties and performance characteristics for specific applications.
6. Applications: Aluminum oxide abrasives find applications in industries such as metalworking, woodworking, automotive, aerospace, and manufacturing. They are used for tasks such as grinding, deburring, sanding, polishing, and surface finishing.