| 摘要 |
In one aspect the invention is directed to a machinable glass-ceramic having a high degree of crystallinity (greater than 50 Vol. %), high mechanical strength (MOR>150 MPa) In accordance with the invention, the machinable glass-ceramics described herein consists essentially of, in weight percent, 35-55% SiO2, 6-18% Al2O3, 12-27% MgO, 3-12% F, 5-25% SrO, 0-20% BaO and 1-7% K2O. The machinable glass-ceramics of the invention have a dielectric constant of <8 (typically being in the range of 6-8) at 25° C. and 1 KHz; a loss tangent of <0.002 at 25° C. and 1 MHz; a CTE in the range of 80-120x10-7/° C. in the temperature range of 25-300° C.; a Poisson's ration of approximately 0.25; and a porosity of 0%.
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