Chemical Properties of Materials
Being an Engineers it importance to have the knowledge of chemical properties of engineering materials. Because most the engineering materials come into contact of other materials react chemically to each other. Due to this chemical reaction they may suffers from chemical deterioration. Some of the chemical properties of engineering materials are listed below –
- Chemical composition
- Atomic bonding
- Corrosion resistance
- Acidity or Alkalinity
Chemical CompositionThe chemical composition of engineering material indicates the elements which are combined together to form that material. Chemical composition of material effects the properties of engineering material very much. The strength, hardness, ductility, brittleness, corrosion resistance, weldability etc. depend on chemical composition of material. Hence, we should also have the knowledge of chemical composition of engineering material. For Example the Chemical compositions of some materials are listed below-
|Sl. No.||Material||Chemical Composition|
|1.||Steel||Fe, Cr, Ni|
|2.||Brass||Cu = 90%, Ni = 10%|
|3.||Bronze||90% Cu, 10% Ni|
|4.||Invar||Fe = 64%, Ni = 36%|
|5.||Gun Metal||Cu = 88%, Tin = 10%, Zn = 2%|
|6.||German Silver or Nickel Silver or Electrum||Cu = 50%, Zn = 30%, Ni = 20%|
|7.||Nichrome||Ni = 60%, Cr = 15%, Fe = 25%|
|8.||Phosphor Bronge||Cu = 89 – 95.50% , Tin = 3.50 -10%, P = 1%|
|9.||Manganin||Cu = 84%, Mn = 12%, Ni = 4%|
|10.||Constantan||Cu = 60%, Ni = 40%|
Atomic BondingAtomic bonding represents how atoms are bounded to each other to form the material. Many properties, such as melting point, boiling point, thermal conductivity and electrical conductivity of materials are governed by atomic bonding of materials. Hence, to understand the properties of materials, it is very important to study the atomic bonding of materials. Atomic bonds in materials are of following types,
- Ionic bond – from by exchanging of valence electrons between atoms.
- Covalent bonds – from by sharing of electrons between atoms.
- Metallic bonds – found in metals.