A glass ceramic article is provided so that a reliable coloring with a defined transmittance is ensured. The reliable coloring of the glass ceramic article is based on a high content of iron oxide of more than 0.1 percent by weight which itself has a strongly coloring effect does not further reduce transmittance but rather interacts with vanadium oxide to attenuate the absorption caused by vanadium oxide.

The present invention relates to an improved cordierite glass-ceramic. In order to improve the materials properties, it is proposed that the glass-ceramic comprising SiO.sub.2, Al.sub.2O.sub.3, MgO and Li.sub.2O contains cordierite as main crystal phase and that a secondary crystal phase of the glass-ceramic comprises high-quartz solid solution and/or keatite solid solution. The invention further relates to a process for producing such a glass-ceramic and the use of such a glass-ceramic.

The present invention relates to glass-ceramic compositions, as well as methods for forming such composition. In particular, the compositions include various polymorphs of silica that provide beneficial thermal expansion characteristics (e.g., a near linear thermal strain). Also described are methods of forming such compositions, as well as connectors including hermetic seals containing such compositions.

A honeycomb structure having crystal phases of aluminum titanate and mullite, which is obtained by sintering a honeycomb molding made of a mixture comprising titania powder, alumina powder, silica powder and mullite powder, the mixture containing 1-10 parts by mass of silica powder and 5-30 parts by mass of mullite powder per the total amount (100 parts by mass) of the titania powder and the alumina powder, and the mullite powder containing 40-60% by mass of particles having particle sizes of 10-50 gm and 5-30% by mass of particles having particle sizes of 3 gm or less, and its production method.

The present invention relates to glass-ceramic compositions, as well as methods for forming such composition. In particular, the compositions include various polymorphs of silica that provide beneficial thermal expansion characteristics (e.g., a near linear thermal strain). Also described are methods of forming such compositions, as well as connectors including hermetic seals containing such compositions.