Alternative Materials for Metal Mirror Design – SupremEX 640XA and AyontEX 13
Aluminum remains the most commonly used metal mirror material for the majority of specialized optical applications. Nevertheless, while aluminum mirrors offer good mechanical/optical properties and reliability at relatively low cost, there are some alternative, higher-performance metal mirror materials available today.
Vastly improved CTE matching of diamond point turned, highly polishable electroless nickel plating on light-weighted mirror substrates – enabled by replacement of aluminum with AyontEX™ 13 or SupremEX® 640XA – benefit many current and future optical systems applications.
Essentially, these new metals occupy a unique niche between aluminum and beryllium in material stiffness, giving design engineers a more optimized material option to consider. The added benefit of reducing bimetallic bending due to CTE differences between the optical-grade nickel plating and the substrate, make Ayontex and Supremex very appealing options for systems that will see wide operating temperature ranges. This means more capability for reflective systems in space, airborne, and cryogenic IR systems.
Applications for SupremEX 640XA and AyontEX 13 Metal Mirror Materials
Although originally focused on industrial opto-mechanical applications, SupremEX® 640XA and AyontEX™ 13 can also be used for high-speed semiconductor fabrication equipment, robotics, and rotating shafts due to the relative advantages of mechanical properties.
These materials are also extremely effective in lightweight thermal management applications, as well as various load-bearing and/or wear-resistant components.
Material Properties of SupremEX 640XA and AyontEX 13:
- Light-weighted AyontEX™ 13 and SupremEX® 640XA spherical test mirrors have been shown to exhibit excellent density, homogeneity, dimensional stability, and isotropy of thermal expansion over temperature on the nanometer scale of measurement.
- Fine, highly dense, randomized particle distribution relates well to strength and isotropic CTE.
- Both materials generally abide by the rule of mixtures to obtain the best compromise of properties.
SupremEX 640XA and AyontEX 13 vs. Aluminum for Metal Mirror Optics:
- SupremEX® 640XA and AyontEX™ 13 are stronger and stiffer than Al6061-T6.
- The CTE match to electroless nickel is about 25-30X better than Al6061-T6.
- Modal frequency is improved by (specific stiffness ratio)^0.5 compared to Al6061-T6.
- Microyield is pending but is expected to be dominated by the Al6061 matrix.
- SupremEX has notable lubricity and wear resistance for sliding contact applications.
- Both materials can be nickel-plated, conversion coated, and black anodized.
- AyontEX™ 13 can be CNC milled and turned similarly in cost to Al6061-T6, SupremEX® 640XA can be machined to similar complexity but polycrystalline tools are required, and machining cost is estimated at about +3X.
- SupremEX® 640XA can be cut on a diamond point turning machine to a non-specular condition but having sufficient form and finish accuracy for application of electroless nickel. AyontEX™ 13 can be diamond point machined to 120-160 Angstroms RMS.
- Overall cost comparison to aluminum is compelling when accounting for similar processing cost starting from billet, along with the relative performance advantages.
Precision USA-Made Metal Mirror Optics Since 1989
CMM Optic is one of the nation’s leading firms specializing in metal mirror manufacturing solutions. From engineering through prototyping all the way to production, our company produces superior optical equipment optimized for your specific application.