Combination K is a type of

composite armor Composite armour is a type of vehicle armour consisting of layers of different material such as metals, plastics, ceramics or air. Most composite armours are lighter than their all-metal equivalent, but instead occupy a larger volume for the sam ...

. It is fitted onto the

Soviet Union The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, ...

tank

T-64 The T-64 is a Soviet tank manufactured in Kharkiv, and designed by Kharkiv Morozov Machine Building Design Bureau. The tank was introduced in the early 1960s. It was a more advanced counterpart to the T-62: the T-64 served in tank divisions, whi ...

Description

Combination K is a three-layer composite armor consisting of an outer and inner layer of steel and a middle layer of

fiberglass Fiberglass (American English) or fibreglass (Commonwealth English) is a common type of fiber-reinforced plastic using glass fiber. The fibers may be randomly arranged, flattened into a sheet called a chopped strand mat, or woven into glass cl ...

glass-reinforced plastic ("steklotekstolit") and a pack of

ceramic A ceramic is any of the various hard, brittle, heat-resistant and corrosion-resistant materials made by shaping and then firing an inorganic, nonmetallic material, such as clay, at a high temperature. Common examples are earthenware, porcelai ...

(allegedly

corundum Corundum is a crystalline form of aluminium oxide () typically containing traces of iron, titanium, vanadium and chromium. It is a rock-forming mineral. It is a naturally transparent material, but can have different colors depending on the ...

) plates. Some

T-72 The T-72 is a family of Soviet/Russian main battle tanks that entered production in 1969. The T-72 was a development of the T-64, which was troubled by high costs and its reliance on immature developmental technology. About 25,000 T-72 tanks ...

tanks have their

gun turret A gun turret (or simply turret) is a mounting platform from which weapons can be fired that affords protection, visibility and ability to turn and aim. A modern gun turret is generally a rotatable weapon mount that houses the crew or mechani ...

frontal armour composed of three layers: outer and inner layers of steel and a middle layer of

sand Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a soil texture, textur ...

quartz Quartz is a hard, crystalline mineral composed of silica ( silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical ...

("kvartz", probably the origin of the "K" in the name; also implies some relationship between the T-64A and the kvartz composite). The gun turrets are

cast Cast may refer to: Music * Cast (band), an English alternative rock band * Cast (Mexican band), a progressive Mexican rock band * The Cast, a Scottish musical duo: Mairi Campbell and Dave Francis * ''Cast'', a 2012 album by Trespassers William ...

with internal cavities on each side of the main

tank gun A tank gun is the main armament of a tank. Modern tank guns are high-velocity, large-caliber artilleries capable of firing kinetic energy penetrators, high-explosive anti-tank, and cannon-launched guided projectiles. Anti-aircraft guns can ...

, which are later filled with the desired

composite material A composite material (also called a composition material or shortened to composite, which is the common name) is a material which is produced from two or more constituent materials. These constituent materials have notably dissimilar chemical or ...

. Some Russian sources describe the material as "peschannye sterzhni" ("sand rods" or more likely "sandbars"), likely made of a form of

silica Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is o ...

similar to

fused silica Fused quartz, fused silica or quartz glass is a glass consisting of almost pure silica (silicon dioxide, SiO2) in amorphous (non-crystalline) form. This differs from all other commercial glasses in which other ingredients are added which change ...

developed in the US for the T95 Medium Tank prototype in the 1952 program for equipping tanks with protection against

shaped charge A shaped charge is an explosive charge shaped to form an explosively formed penetrator (EFP) to focus the effect of the explosive's energy. Different types of shaped charges are used for various purposes such as cutting and forming metal, init ...

s and

high-explosive anti-tank High-explosive anti-tank (HEAT) is the effect of a shaped charge explosive that uses the Munroe effect to penetrate heavy armor. The warhead functions by having an explosive charge collapse a metal liner inside the warhead into a high-velocity ...

(HEAT) rounds without sacrificing protection against

kinetic energy penetrator A kinetic energy penetrator (KEP), also known as long-rod penetrator (LRP), is a type of ammunition designed to penetrate vehicle armour using a flechette-like, high-sectional density projectile. Like a bullet or kinetic energy weapon, this type ...

s. The same design of cast-steel turret with cavities for composite insets is reportedly used also in some earlier variants of

T-80 The T-80 is a main battle tank (MBT) that was designed and manufactured in the former Soviet Union and manufactured in Russia. The T-80 is based on the T-64, while incorporating features from the later T-72. The chief designer of the T-80 was ...

and

T-90 The T-90 is a third-generation Russian main battle tank. It uses a 125mm 2A46 smoothbore main gun, the 1A45T fire-control system, an upgraded engine, and gunner's thermal sight. Standard protective measures include a blend of steel and comp ...

tanks with cast turrets.http://www.knox.army.mil/center/ocoa/armormag/backissues/1990s/1999/ja99/4warford99.pdf The more modern T-90A and T-90M, use an

Object 187 Object 187 (Объект 187), was a Soviet experimental main battle tank developed between the late 1980s and middle 1990s. It remains a relatively unpublicized development because of high levels of secrecy surrounding the project. Design The tank ...

-derived slab-sided welded turret, which offers an easier and more optimal way to mount inserts of various forms, including non-explosive

reactive armour Reactive armour is a type of vehicle armour that reacts in some way to the impact of a weapon to reduce the damage done to the vehicle being protected. It is most effective in protecting against shaped charges and specially hardened kinetic ene ...

(NERA). More effective inserts can lead to radically increased protection. Reportedly, during the

Second Chechen War The Second Chechen War (russian: Втора́я чече́нская война́, ) took place in Chechnya and the border regions of the North Caucasus between the Russian Federation and the Chechen Republic of Ichkeria, from August 1999 ...

no T-90A suffered a penetrating hit, with some allegedly surviving up to seven

RPG-7 The RPG-7 (russian: link=no, РПГ-7, Ручной Противотанковый Гранатомёт, Ruchnoy Protivotankoviy Granatomyot) is a portable, reusable, unguided, shoulder-launched, anti-tank, rocket-propelled grenade launcher. T ...

hits that failed to penetrate the armor.

References

Vehicle armour {{mil-hist-stub