Alloys | Chemistry for JAMB PDF Download

Introduction

• Alloys are metallic substances composed of two or more elements, with at least one being a metal.
• They are formed by mixing molten metals or by the process of solid-state diffusion.
• Alloys exhibit enhanced properties compared to pure metals, making them valuable for various applications.

Alloy Definition and Examples

Alloys are materials made by combining two or more metallic elements, where at least one element is a metal.
Examples of alloys:

• a. Bronze: Copper (Cu) + Tin (Sn)
• b. Brass: Copper (Cu) + Zinc (Zn)
• c. Stainless Steel: Iron (Fe) + Chromium (Cr) + Nickel (Ni)
• d. Duralumin: Aluminum (Al) + Copper (Cu) + Magnesium (Mg)
• e. Soft Solder: Tin (Sn) + Lead (Pb)
• f. Permallory: Nickel (Ni) + Iron (Fe)
• g. Alnico: Aluminum (Al) + Nickel (Ni) + Cobalt (Co)

Types of Steel (e.g., Stainless Steel)

Stainless Steel:

• Constituents: Iron (Fe) + Chromium (Cr) + Nickel (Ni)
• Properties and Uses:
  • High resistance to corrosion and staining, making it ideal for kitchen utensils, cutlery, and medical instruments.
  • Excellent strength and durability, widely used in construction, automotive, and aerospace industries.

Brass, Bronze, Duralumin, Soft Solder, Permallory, and Alnico

1. Brass:

• Constituents: Copper (Cu) + Zinc (Zn)
• Properties and Uses:
  • High malleability and low melting point, used in musical instruments, plumbing fittings, and decorative items.
  • Exhibits antimicrobial properties, making it suitable for doorknobs and sanitary fittings.

2. Bronze:

• Constituents: Copper (Cu) + Tin (Sn)
• Properties and Uses:
  • Greater hardness and resistance to corrosion than pure copper, used in statues, coins, and electrical connectors.
  • Excellent casting properties, widely employed in art, sculptures, and musical instruments.

3. Duralumin:

• Constituents: Aluminum (Al) + Copper (Cu) + Magnesium (Mg)
• Properties and Uses:
  • Lightweight with high strength and durability, utilized in aircraft construction, automotive parts, and structural components.

4. Soft Solder:

• Constituents: Tin (Sn) + Lead (Pb)
• Properties and Uses:
  • Low melting point, used for joining metals in electrical and plumbing applications, as well as in electronic circuit boards.

5. Permallory:

• Constituents: Nickel (Ni) + Iron (Fe)
• Properties and Uses:
  • Exhibits high magnetic permeability, used in magnetic shielding applications, telecommunication devices, and transformers.

6. Alnico:

• Constituents: Aluminum (Al) + Nickel (Ni) + Cobalt (Co)
• Properties and Uses:
  • High coercivity and temperature stability, used in permanent magnets, electric guitar pickups, and sensors.

Comparison of Alloys to Pure Metals

Alloys generally possess superior properties compared to pure metals, such as:

• Increased strength, hardness, and durability.
• Enhanced resistance to corrosion, wear, and tarnishing.
• Altered melting and boiling points, allowing for specific applications.
• Improved electrical conductivity or magnetic properties.

Alloys offer a broader range of applications due to their tailored properties, making them essential in various industries.