ALLOYS
- An alloy is a homogeneous mixture of two or more metals or of one or more metals with certain non-metallic elements.
- The properties of alloys are often different from those of their components.
- Pure gold is brittle to be used. The addition of a small percentage of copper enhances its strength and utility.
Amalgam
- An amalgam is an alloy of mercury with another metal.
- These alloys are formed through metallic bonding with the electrostatic force of attraction between the electrons and the positively charged metal ions. Silver tin amalgam is used for a dental fillings.
Reasons for alloying:
- To modify appearance and colour
- To modify chemical activity.
- To lower the melting point.
- To increase hardness and tensile strength.
- To increase resistance to electricity.
Method of making alloys
- By fusing the metals together. E.g., Brass is made by melting zinc and copper.
- By compressing finely divided metals. E.g., Wood metal: an alloy of lead, tin, bismuth and cadmium powder is a fusible alloy.
Alloys as solid solutions:
- Alloys can be considered as solid solutions in which the metal with high concentration is solvent and other metals are solute.
- For example, brass is a solid solution of zinc (solute) in copper (solvent).
Types of Alloys
- Based on the presence of Iron, alloys can be classified into:
- Ferrous alloys: Contain Iron as a major component. A few examples of ferrous alloys are Stainless Steel, Nickel Steel etc.
- Non-ferrous alloys: These alloys do not contain Iron as a major component. For example, Aluminium alloy, Copper alloy etc.
Also Read
- Carbon / கார்பன்
- Nitrogen and their compounds / நைட்ரஜன் மற்றும் அதன் சேர்மங்கள்
- Fertilizer / உரங்கள்
- Pesticides / களைக்கொல்லி
- Insecticides / பூச்சிக்கொல்லி
- Blood and blood circulation / இரத்தம் மற்றும் இரத்த சுழற்சி மண்டலங்கள்
- Endocrine system reproductive system / நாளமில்லா சுரப்பி மண்டலம், இனப்பெருக்க மண்டலம்
- Nature of universe / பேரண்டத்தில் இயல்புகள்
- General Scientific Law / பொது அறிவியல் விதிகள்
- Heat, Light and Sound / ஒளி,ஒலி மற்றும் வெப்பம்
- Electricity and Electronics / மின்னியல் மற்றும் மின்னணுவியல்