A colored glass-ceramic and method of making it. The glass-ceramic has a primary crystal phase selected from the group consisting of beta-quartz solid solution and beta-spodumene solid solution, containing an amount of TiO.sub.2 effective as a nucleating agent up to 6% by weight, 700-900 ppm Fe.sub.2 O.sub.3 and 550-3000 ppm Co.sub.3 O.sub.4, the glass-ceramic having a beta-quartz solid solution as a primary crystal phase being transparent and having a color defined by the color coordinates x=0.2200-0.3100, y=0.0200-0.2400 falling within color box ABCDA in FIG. 1 in the drawings, and the glass-ceramic having a beta-spodumene solid solution as a primary crystal phase being opaque and having a color defined by the color coordinates x=0.2480-0.2880, y=0.2000-0.3150 falling within color box JKLMJ in FIG. 2 in the drawings. Reddish-purple and violet colors are obtained in transparent, beta-quartz glass-ceramics, while light to dark blue colors are obtained in opaque, beta-spodumene glass-ceramics.
There is disclosed a stove, with a smooth-top cooktop, for cooking food, the stove comprising: a stove body; a smooth-top cooktop to cook food thereon; and at least one heat source disposed adjacent to a cooking surface of said cooktop. The cooktop comprises glass ceramic with an upper layer and an inner layer, with the upper layer comprising a different glass ceramic material than the inner layer. The upper layer is configured to minimize surface defects such as fissures, cracks, pits, and pores. The inner layer is configured to provide resistance to impact to the upper layer from cooking utensils being dropped onto the upper layer of the smooth-top cooktop, and at least the inner layer of the glass ceramic being configured to obscure visibility of the at least one heat source, through the upper layer of the glass ceramic.
These color television (CTV) panel tint glasses involve using base CTV panel glass compositions with enhanced levels of Ni and Co colorants. The approach uses non-lead CTV panel glass compositions with high levels of Ni and Co oxide as colorant glasses for tinting clear CTV non-lead panel glass. Nickel oxide was varied from 2 to 18%, while cobalt oxide was varied from 0.2 to 2%. A preferred range of compositions with cobalt oxide levels below 1% and nickel oxide levels below 10% was found to be very acceptable for CTV panel colorants.
The cooking panel is made from an opaque glass-ceramic material uniformly colored throughout and having keatite mixed crystals as the predominant crystalline phase. The cooking panel is made by ceramicizing a ceramicizable glass or a transparent glass-ceramic with high quartz mixed crystals as the predominant crystalline phase in a definite color location range with a brightness parameter value (L*) less than 85 and a color shade and chromaticity according to its later service and wear pattern. The cooking panel makes deposited material, such as dirt and the like, less conspicuous.
A negative thermal expansion glass ceramic having a negative coefficient of thermal expansion, which is a sufficiently large absolute value in a temperature range of -40.degree. C. to +160.degree. C. and a method for producing the same are provided. The negative thermal expansion glass ceramic has a coefficient of thermal expansion of -25 to -100.times.10.sup.-7 /.degree. C. in the temperature range of -40.degree. C. to +160.degree. C., and comprises main crystalline phases which are one or more types selected from a group consisting of .beta.-eucryptite solid solution (.beta.-Li.sub.2 O.multidot.Al.sub.2 O.sub.3.multidot.2SiO.sub.2 solid solution), .beta.-eucryptite (.beta.-Li.sub.2 O.multidot.Al.sub.2 O.sub.3.multidot.2SiO.sub.2), .beta.-quartz solid solution (.beta.-SiO.sub.2 solid solution), and .beta.-quartz (.beta.-SiO.sub.2), wherein a total amount of crystals of the main crystalline phases can be 70 to 100% in mass percent.
The method produces a glass-ceramic article substantially in the form of a plate with improved high temperature difference resistance or strength. The glass-ceramic article contains keatite mixed crystals (KMK) or high quartz mixed crystals (HQMK) as well as the keatite mixed crystals (KMK). The method includes heating a glass-ceramic in a high quartz mixed crystal state to form the keatite mixed crystals with a heating rate of 20 K/min to 150 K/min, preferably more than 15 K/min, especially preferably more than 20 K/min. These high heating rates increase the temperature difference resistance.
