Tank Drawing

To effectively protect the tank and its crew, tank armour must counter a wide variety of antitank threats. Protection against kinetic energy penetrators and high explosive anti-tank (HEAT) shells fired by other tanks is of primary importance, but tank armour also aims to protect against infantry antitank missiles, ATGMs, antitank mines, bombs, direct artillery hits, and (less often) nuclear, biological and chemical threats, any of which could disable or destroy a tank or its crew.
Steel armour plate was the earliest type of armour. The Germans pioneered the use of face hardened steel during World War II and the Soviets also achieved improved protection with sloped armour technology. World War II developments also spelled the eventual doom of homogeneous steel armour with the development of shaped-charge warheads, exemplified by the Panzerfaust and bazooka infantry weapons which were lethally effective, despite some early success with spaced armour. Magnetic mines led to the development of anti-magnetic paste and paint.
British tank researchers took the next step with the development of Chobham armour, or more generally composite armour, incorporating ceramics and plastics in a resin matrix between steel plates, which provided good protection against HEAT weapons. Squash head warheads led to anti-spall armour linings, and KEPs led to the inclusion of exotic materials like a matrix of depleted uranium into a composite armour configuration.
Reactive armour consists of small explosive-filled metal boxes that detonate when hit by the metallic jet projected by an exploding HEAT warhead, causing their metal plates to disrupt it. Tandem warheads defeat reactive armour by causing the armour to detonate prematurely. Modern Reactive armour protects itself from Tandem warheads by having a thicker front metal plate to prevent the precursor charge from detonating the explosive in the reactive armour. Reactive armours can also reduce the penetrative abilities of kinetic energy penetrators by deforming the penetrator with the metal plates on the Reactive armour, thereby reducing its effectiveness against the main armour of the tank.