Suramya's Blog : Welcome to my crazy life…

June 16, 2021

New material created that shows zero heat expansion from 4 to 1,400 K

Filed under: Emerging Tech,My Thoughts — Suramya @ 11:53 PM

One of the issues with high performance systems is that they generate a lot of great and heat usually causes the material they are made of to expand. Similarly cold temperatures causes materials to contract and this can cause problems because the constant expansion and contraction weakens the material. Due to this there is a lot of research that is happening to find materials that don’t expand/contract so much with temperature changes.

Researches from Australia have created a material that has zero thermal expansion. The material made out of scandium, aluminum, tungsten and oxygen did not expand or contract even when subjected to changes from 4 to 1,400 Kelvin (-269 to 1126 °C, -452 to 2059 °F). This makes it could make orthorhombic Sc1.5Al0.5W3O12 very useful for devices that need to work in extreme temperatures. This is a phenomenal achievement with a ton of uses. However the components to make the material are not cheap especially Scandium which is one of the most expensive elements currently. According to folks online it can cost about ~$120/gram so unless other elements can be used or we find a easy to mine/extract source of the metal the material is not something that we will see in general use anytime soon.

Zero thermal expansion (ZTE) is a rare physical property; however, if accessible, these ZTE or near ZTE materials can be widely applied in electronic devices and aerospace engineering in addition to being of significant fundamental interest. ZTE materials illustrate this property over a certain temperature range. Here, orthorhombic (Pnca space group) Sc1.5Al0.5W3O12 is demonstrated to deliver ZTE over the widest temperature reported to date, from 4 to 1400 K, with a coefficient of thermal expansion of αv = −6(14) × 10–8 K–1. Sc1.5Al0.5W3O12 maybe is one of the most thermally stable materials known based on the temperature range of stability and the consistent thermal expansion coefficients observed along the crystallographic axes and volumetrically. Furthermore, this work demonstrates the atomic perturbations that lead to ZTE and how varying the Sc:Al ratio can alter the coefficient of thermal expansion.

This material has a ton of uses. For example, this would be very useful in making items or structures in space. Since the temperature in space can vary from ~260 degrees Celsius in the sunlight to below -100 degrees Celsius in the shade we need materials with a low expansion coefficient. Another use case is for a coating on hypersonic jets, recently China has created a Mach 30 wind tunnel which allows them to test prototypes for planes that can fly at Mac 30. At that speed the air turns into plasma due to the friction and requires the planes to be made (or atleast coated with) a material that has low/zero heat expansion. If these planes are coated with this material then the only limitation on the speed would be how much thrust the engines can provide.

I can also see it being used for military jets/missiles etc to allow them to fly faster without damage and on rockets to make them more durable with lesser weight disadvantages.

The paper was published in Chemistry of Materials journal and though the work has a long way to go before it is commercially available it does have some fascinating potential.

Source: Extraordinary new material shows zero heat expansion from 4 to 1,400 K

– Suramya

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