Thisbook,entitledLowThermal Expansion Glass Ceramics,isoneofaseries reporting on research and development activities on products and processes conducted by the Schott AG. Thescienti?callyfoundeddevelopmentofnewproductsandtechnicalp- cesses has traditionally been of vital importance at Schott and has always been performed on a scale determined by the prospects for application of our special glasses. The scale has increased enormously since the reconstruction of the Schott Glaswerke in Mainz. The range of expert knowledge required for that could never have been supplied by Schott alone. It is also a tradition in our company to cultivate collaboration with customers, universities, and research institutes. Publications in numerous technical journals, which since 1969 we have edited to a regular timeplan as Forschungsberichte - 'research reports'-formedthebasisofthiscooperation.Theycontainup-to-dateinf- mation on various topics for the expert but are not suited as survey material for those whose standpoint is more remote. This is the point where we would like to place our series, to stimulate the exchange of thoughts, so that we can consider from di?erent points of view the possibilities o?ered by those incredibly versatile materials, glass and glass ceramics. We would like to show scientists and engineers, interested customers,andfriendsandemployeesofour?rmtheknowledgethathasbeen won through our research and development at Schott in cooperation with the users of our materials.

This book appears in the authoritative series reporting the international research and development activities conducted by the Schott group of companies. This series provides an overview of Schott's activities for scientists, engineers, and managers from all branches of industry worldwide in which glasses and glass ceramics are of interest. Each volume begins with a chapter providing a general idea of the current problems, results, and trends relating to the subjects treated.

This new extended edition describes the fundamental principles, the manufacturing process, and applications of low thermal expansion glass ceramics. The composition, structure, and stability of polycrystalline materials having a low thermal expansion are described, and it is shown how low thermal expansion glass ceramics can be manufactured from appropriately chosen glass compositions. Examples illustrate the formation of this type of glass ceramic by utilizing normal production processes together with controlled crystallization. Thus glass ceramics with thermal coefficients of expansion of less than 0.3 x 10(-6)K(-1) can be obtained. Even for the mass production of high-quality cooktop panels (Ceran®., oven windows, and other household appliances a high reproducibility of the properties is achieved. Special glass ceramics (Zerodur®. for technological and scientific applications such as high-precision optics or large astronomical mirrors are likewise discussed. The completely revised edition also features new sections on glass-ceramic applications, with details on their performance, CDC-grinding, and laser gyroscopes containing Zerodur®..