Home - ALLVAR Negative Coefficient of Thermal Expansion Alloys

ALLVAR Alloys are the only Negative

Thermal Expansion Metals in the World.

ALLVAR Alloy 30 is the first negative thermal expansion metal with a coefficient of thermal expansion (CTE) of -30 ppm/°C at 20°C. This new property opens the door for engineers to control thermal expansion across a wide range of applications.

Latest from our Video Series: June 11, 2020

Factors That Influence Thermal Focus Shift - A Thin Lens Model

As a supplement to Deriving a Passive Athermalization Figure of Merit for Length Comparison, this video explores the effect of thermal expansion and refractive index on a thin lens' thermal focus shift. Different classes of lens materials are then compared using this simple equation.

Deriving a Passive Athermalization Figure of Merit for Length Comparison

Infrared optic lens materials present a unique challenge to opto-mechanical design. In this video, we derive a Figure of Merit (FOM) that describes a commonly used passive solution to the infrared optic negative thermal focus shift problem. This FOM is used in subsequent videos to compare the performance of different optic housing materials.

Length Effects of Different Passive Athermalization Materials.

The choice of housing materials for athermalizing infrared optics can drastically change the length of the optic. This video uses a previously derived Figure of Merit (FOM) to estimate the length of a passively athermal housing based on housing material selection. A 40% reduction in length is realized by replacing Aluminum with ALLVAR Alloy 30 in the commonly used Aluminum-Delrin material pair.