Zero-expansion glass ceramic ZERODUR: recent developments reveal high potential

ZERODUR® is a well-established material in astronomy and all fields of applications where temperature gradients might limit extreme precision and stability. Together with its rich heritage come a series of recent developments, which reveal the potential of the material for broader and more demanding applications. The outstanding degree of light-weighting achieved with progress in CNC grinding in the last two years shows its high suitability for space telescope mirrors. This is supported by new data on strength enabling higher mechanical loads. Also ground based telescopes benefit from the improved light-weight processing such as solar telescopes and downstream mirrors of extremely large telescopes. More and better data have been collected demonstrating the unique CTE homogeneity of ZERODUR® and its very high reproducibility a necessary precondition for large series mirror production. Deliveries of more than 250 ZERODUR mirrors of 1.5 m in diameter prove the availability of robust industrial serial production capability inevitable for ELT mirror segment production.

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