Editing Invar (section)

== Variations ==
There are variations of the original Invar material that have slightly different coefficient of thermal expansion such as:
*'''Inovco''', which is Fe–33Ni–4.5Co and has an <var>α</var> of 0.55&nbsp;ppm/°C (from 20 to 100&nbsp;°C).{{Cn|date=June 2023}}{{Examples|date=June 2023}}
*'''FeNi42''' (for example NILO alloy 42), which has a nickel content of 42% and {{nowrap|<var>α</var> ≈ 5.3&nbsp;ppm/°C}}, matching that of [[silicon]], is widely used as lead frame material for integrated circuits, etc.{{Cn|date=June 2023}}
*FeNiCo alloys—named '''[[Kovar]]''' or Dilver P—that have the same expansion behaviour (~{{nowrap|5&nbsp;ppm/°C}}) and form strong bonds with molten [[borosilicate glass]], and because of that are used for [[glass-to-metal seal]]s, and to support optical parts in a wide range of temperatures and applications, such as [[satellites]].{{Cn|date=June 2023}}
*'''[[Elinvar]]''' has a near-constant [[modulus of elasticity]], making it valuable for wristwatch [[balance wheel]]s, [[spring scales]], and other spring-based measuring instruments.