| 摘要 |
The invention relates to ceramics and glass ceramics exhibiting low and/or negative coefficients of thermal expansion. The invention therefore addresses the problem of indicating a possible method which, at minimized cost and with low melting temperature, can produce ceramics and/or glass ceramics exhibiting low or else negative thermal expansion. According to the invention, the problem is solved via crystalline phases of the type AM2Si2-yGeyO7 (A = Sr and Ba, and M = Zn, Mg, Ni, Co, Fe, Cu, Mn, where Sr, Ba and Zn must be present) which can be produced by conventional ceramic processes or by crystallization from glasses. The stated compositions form solid solutions where the elements mentioned as component M can replace one another at almost any desired concentration but the concentration of Zn must always be at least 50 % of the entirety of components listed as M. The stoichiometry of these silicates, and their structure, can differ to a variable extent. |
