| 摘要 |
PROBLEM TO BE SOLVED: To provide a glass ceramic substrate made of a transparent colored LAS glass ceramic having a particular composition and if necessary an additional coloring oxide up to a maximum of 1.0 mass% in total, and containing a gradient layer comprising keatite solid solution, and a high-quartz solid solution as a main crystalline phase, and including a nucleus present beneath thereof, and in which the keatite solid solution having a depth of 10 μm or more exceeds 50% of the total of the high-quartz solid solution percentage and the keatite solid solution percentage.SOLUTION: In the production process, the ceramization includes a crystalline transition step for transitioning only a portion of high-quartz solid solution to keatite solid solution for a period of 1 to 25 minutes at the maximum temperature in a range of 910° to 980°.SELECTED DRAWING: Figure 3 |
