Revolutionize athermalization with ALLVAR Alloys, the only Negative Thermal Expansion Metals in the World.

Passive Athermalization made easy.

The process of removing thermal effects from a system is called athermalization. Creating an athermal design that actively athermalizes a system is challenging, and often increases the weight and complexity of a system. Passive athermalization achieves the same results as an active system, but without using powered systems or requiring outside feedback. It requires iterative changes and tweaks to hone the thermal changes of individual components in a design, so that they together work in unison to passively counteract thermal effects. These systems are challenging to design, manufacture, and test. ALLVAR Alloys makes this process much easier.

Targeted Thermal Expansion.

Negative thermal expansion ALLVAR Alloys allow engineers and designers to target a specific thermal expansion for their system. Designers select a specific thermal expansion, from –30 ppm/°C to a joined materials positive coefficient of thermal expansion, and incorporate a calculated length of ALLVAR Alloy 30 to hone in on a target CTE. Being able to tailor a specific CTE flips the design paradigm on its head. 



Maintaining performance and structural integrity of optical systems over a wide temperature range (passive athermalization) has been a practical and technical struggle for decades. Eliminate unreliable optical performance by simply replacing traditional athermalization solutions with the only negative CTE alloy in the world, ALLVAR Alloy 30. This negative CTE innovation renders traditional design paradigms inefficient and enables smaller, lighter optical system designs that were previously impossible.


Drastic temperature changes and thermal cycling can cause brutal wear and tear on a variety of fastened assemblies. When tight margins of safety create a near-unobtainable preload requirement, securing these assemblies can be challenging. Negative thermal expansion alloys can help solve your tough thermal fastening issues with constant force-load washers, ensuring a safe and reliable system with joints that overcome wide temperature ranges.


Negative Thermal Expansion ALLVAR Alloys can compensate for the expansion and contraction of other materials. ALLVAR Alloy 30 can be used to create tailored thermal expansions in metering structures, telescopes, or high precision scientific instruments. The ultra-stable struts shown above were designed with ALLVAR Alloy 30, titanium 6Al4V, and invar and have a near zero CTE at room temperature.

Component CTE Mismatch
SWaP-C Challenges
Fastener Slip
Optical Tolerancing
CTE Control
Fastener Fatigue
Maintaining Performance at Temperature
Narrow Safety Margins
Fastener Loosening


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Video Resources - Learn More About ALLVAR and Negative Thermal Expansion

Click the images below to get our selection of videos and learn more about our company, our technology and our products.

ALLVAR University

Watch our videos to learn more about negative CTE and how it can be precisely compensate positive CTE components in athermal assemblies.

Demonstration Videos

Our demonstration videos show how important a washer can be, and how a simple change in Optics can eliminate thermal focus shift.

Meet Our Team

Meet our team, from our founder to our engineers, and hear their perspective on their new negative CTE alloys.

Watch a Webinar

Interested in a longer lesson on negative CTE and ALLVAR Alloys? Watch our webinar to get the details.

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