Editing Composite armour (section)

==History==
Some early [[ironclads]] used armor composed of multiple layers of thinner armor bolted or welded together. The results were greatly less effective for a given overall thickness than a single plate, but was done because making thicker plates or plates with different metallurgical properties through their thickness (for example [[Harvey armor]]) was prohibitively expensive or too technically challenging. [[Teak]] was used to sandwich layers that could not be easily fitted together, or provide a backing to catch splinters.<ref>{{cite journal|title=Armor for Ships of War|author=P. R. Alger|year=1895 |journal = Proceedings of the US Naval Institute|volume =21|url=https://www.usni.org/magazines/proceedings/1895/october/armor-ships-war}}</ref>

During WWII, in an effort to provide protection against the [[German Army (1935–1945)|German Army’s]] [[Panzerfaust]] anti-tank weapon, an [[M4 Sherman|M4A3]] was fitted with an armor “kit” incorporating a mixture of quartz gravel, asphalt and wood flour known as “HCR2.” This add-on armor was successfully live-fire tested in September 1945 against both the German Panzerfaust and 76mm High-Velocity Armor Piercing (HVAP) ammunition.<ref>{{Cite web |last=Warford |first=James M. |title=ARMOR Magazine Jul-Aug 1999, p.16 |url=https://www.benning.army.mil/armor/eARMOR/content/issues/1999/JUL_AUG/ArmorJulyAugust1999web.pdf |url-status=dead |archive-url=https://web.archive.org/web/20170125193549/https://www.benning.army.mil/armor/eARMOR/content/issues/1999/JUL_AUG/ArmorJulyAugust1999web.pdf|archive-date=2017-01-25 }}</ref> Aside from this early test, the first serious development began as part of the [[US Army]]'s [[T95 Medium Tank|T95]] experimental series from the mid-1950s. The T95 featured ''siliceous-cored armour'' which contained a plate of [[fused silica]] glass between rolled [[steel]] plates. The stopping power of glass exceeds that of steel armour on a thickness basis and in many cases glass is more than twice as effective as steel on a thickness basis. Although the T95 never entered production, a number of its concepts were used on the [[M60 Patton]], and during the development stage (as the XM60) the siliceous-cored armour was at least considered for use, although it was not a feature of the production vehicles.<ref name=xm60/>

The first widespread use of a composite armour appears to have been on the [[Soviet Union|Soviet]] [[T-64]]. It used an armour known as ''[[combination K]]'', which apparently is [[glass-reinforced plastic]] sandwiched between inner and outer steel layers. Through a mechanism called [[thixotropy]], the [[resin]] changes to a fluid under constant pressure, allowing the armour to be [[moulded]] into curved shapes. Later models of the T-64, along with newer designs, use a [[boron carbide]]-filled resin [[aggregate (composite)|aggregate]] for greatly improved protection{{citation needed|date=September 2016}} . The Soviets also invested heavily in [[reactive armour]], which allowed them some ability to control quality, even after production.

Among NATO nations and allies, the most common type of [[composite material|composite]] armour today is [[Chobham armour]],{{citation needed|date=September 2016}} first developed and used by the British in the experimental [[FV 4211 tank]], which was based on [[Chieftain tank]] components. Chobham uses multiple non-explosive reactive armour plates (NERA), which sandwich a layer of elastomer (like rubber) between two plates of steel armour. This was shown to dramatically increase the resistance to HEAT projectiles, even in comparison to other composite armour designs. Chobham was such an improvement that it was soon used on the new U.S. [[M1 Abrams]] [[main battle tank]] (MBT) as well. The need to mount multiple angled plates, along with an outer steel layer to protect the armour array, gives the [[Challenger 2|Challenger]] and Abrams their "slab sided" look.

The Soviets/Russians had a similar composite armour to the West's own "NERA", with rubber sandwiches between plates of steel.<ref>{{Cite journal |title=T-72B MBT – The First Look at Soviet Special Armor |url=https://tankandafvnews.com/2015/06/12/t-72b-turret-armor-exposed/ |journal=Journal of Military Ordnance |date=12 June 2015 |pages=4–8}}</ref> This armour was confirmed to be inside the T-72B's "Super Dolly Parton" armour, but is suspected to be inside the T-80A as well, since it is unlikely the Soviets would put worse armour in their "premier" tank.