Abstract: A lithium-containing, transparent glass-ceramic material is provided. The material has low thermal expansion and has an amorphous, lithium-depleted, vitreous surface zone. The zone is at least 50 nm thick on all sides and encloses a crystalline interior, which has high transmission. The material includes a transition region connecting the zone and the interior.

Abstract: A lithium-containing, transparent glass-ceramic material is provided. The material has low thermal expansion and has an amorphous, lithium-depleted, vitreous surface zone. The zone is at least 50 nm thick on all sides and encloses a crystalline interior, which has high transmission. The material includes a transition region connecting the zone and the interior.

Abstract: A lithium-containing, transparent glass-ceramic material is provided. The material has low thermal expansion and has an amorphous, lithium-depleted, vitreous surface zone. The zone is at least 50 nm thick on all sides and encloses a crystalline interior, which has high transmission. The material includes a transition region connecting the zone and the interior.

Abstract: The method produces a reshaped glass-ceramic article by forced reshaping of a flat green glass part during a ceramicizing process with temporarily lowered viscosity due to crystallization heat. To perform the forced reshaping economically the forced reshaping takes place in a continuous oven for ceramicizing and in an oven section in which the viscosity of the green glass part is temporarily lowered as a result of crystallization heat. An apparatus for performing the process is provided in the continuous oven including different active reshaping devices and/or a hollow mold. The method produces glass-ceramic articles with undamaged surfaces corresponding to surfaces produced during the making of the green glass part (smooth or structured, e.g. knobbed).

Abstract: In order to obtain glass or glass ceramic materials having increased strength, a method is provided for producing glass or glass ceramic articles, which comprises: producing an initial glass body, mounting the initial glass body on a gas cushion between a levitation support and the initial glass body, and at least partially ceramizing the initial glass body on the levitation support. The levitation support comprises at least one continuous surface region having at least one gas feed region where levitation gas for the gas cushion is fed out from the levitation support, and at least one gas discharge region where gas from the gas cushion is at least partially discharged into the levitation support.

Abstract: A lithium-containing, transparent glass-ceramic material is provided. The material has low thermal expansion and has an amorphous, lithium-depleted, vitreous surface zone. The zone is at least 50 nm thick on all sides and encloses a crystalline interior, which has high transmission. The material includes a transition region connecting the zone and the interior.

Abstract: In order to obtain glass or glass ceramic materials having increased strength, the invention provides a method for producing glass or glass ceramic articles, which comprises the steps: producing an initial glass body (11), mounting the initial glass body (11) on a gas cushion (13) between a levitation support (1) and the initial glass body (11), and at least partially ceramizing the initial glass body (11) on the levitation support (1). The levitation support comprises at least one continuous surface region (3) having at least one gas feed region (151, 152, 153) where levitation gas for the gas cushion (13) is fed out from the levitation support, and at least one gas discharge region (171 172, 173) where gas from the gas cushion (13) is at least partially discharged into the levitation support.

Abstract: The apparatus performs a forced reshaping of a flat green glass part during a ceramicizing process in which the viscosity of the glass is temporarily lowered due to crystallization heat. The apparatus includes a continuous furnace (3) for the ceramicizing process: a reshaping device (2?) provided with activating openings (6); and vertically movable pressure-operated reshaping tools (9) arranged in the reshaping device (2?). The furnace (3) is provided with lateral openings (4) for temporarily connecting activating lines (8) to the activating openings (6) of the reshaping device (2?) in a sealed manner in order to operate the reshaping tools (9) by supplying pressurized air to the reshaping device or by producing a low pressure in the reshaping device (2?).

Abstract: In the process for partially shaping, a glass/glass ceramic article (5) is held on a planar support plate (1) by suction. The glass/glass ceramic article is heated to soften it, so that it has a viscosity below 106 dPa·s. After the softening one or more shaping dies (4) is or are moved upward through an opening or respective openings (3) in the support plate to form raised regions in the softened glass/glass ceramic article (5). The suction force is produced by a low pressure in a hollow compartment (2) below the support plate (1) and acts on the glass/glass ceramic article (5) by means of a gap (G) formed between each shaping die (4) and the support plate. Additional openings can be provided in the support plate and/or in one or more of the shaping dies to assist in applying the suction force to the glass/glass ceramic article. After solidification of the softened glass/glass-ceramic article the shaping die or dies (4) is or are withdrawn.

Abstract: In order to obtain glass or glass ceramic materials having increased strength, the invention provides a method for producing glass or glass ceramic articles, which comprises the steps: producing an initial glass body (11), mounting the initial glass body (11) on a gas cushion (13) between a levitation support (1) and the initial glass body (11), and at least partially ceramizing the initial glass body (11) on the levitation support (1). The levitation support comprises at least one continuous surface region (3) having at least one gas feed region (151, 152, 153) where levitation gas for the gas cushion (13) is fed out from the levitation support, and at least one gas discharge region (171 172, 173) where gas from the gas cushion (13) is at least partially discharged into the levitation support.

Abstract: The method produces a reshaped glass-ceramic article by forced reshaping of a flat green glass part during a ceramicizing process with temporarily lowered viscosity due to crystallization heat. To perform the forced reshaping economically the forced reshaping takes place in a continuous oven for ceramicizing and in an oven section in which the viscosity of the green glass part is temporarily lowered as a result of crystallization heat. An apparatus for performing the process is provided in the continuous oven including different active reshaping devices and/or a hollow mold. The method produces glass-ceramic articles with undamaged surfaces corresponding to surfaces produced during the making of the green glass part (smooth or structured, e.g. knobbed).

Abstract: In the process for partially shaping, a glass/glass ceramic article (5) is held on a planar support plate (1) by suction. The glass/glass ceramic article is heated to soften it, so that it has a viscosity below 106 dPa·s. After the softening one or more shaping dies (4) is or are moved upward through an opening or respective openings (3) in the support plate to form raised regions in the softened glass/glass ceramic article (5). The suction force is produced by a low pressure in a hollow compartment (2) below the support plate (1) and acts on the glass/glass ceramic article (5) by means of a gap (G) formed between each shaping die (4) and the support plate. Additional openings can be provided in the support plate and/or in one or more of the shaping dies to assist in applying the suction force to the glass/glass ceramic article. After solidification of the softened glass/glass-ceramic article the shaping die or dies (4) is or are withdrawn.

Abstract: In the process for partially shaping, a glass/glass ceramic article (5) is held on a planar support plate (1) by suction. The glass/glass ceramic article is heated to soften it, so that it has a viscosity below 106 dPa•s. After the softening one or more shaping dies (4) is or are moved upward through an opening or respective openings (3) in the support plate to form raised regions in the softened glass/glass ceramic article (5). The suction force is produced by a low pressure in a hollow compartment (2) below the support plate (1) and acts on the glass/glass ceramic article (5) by means of a gap (G) formed between each shaping die (4) and the support plate. Additional openings can be provided in the support plate and/or in one or more of the shaping dies to assist in applying the suction force to the glass/glass ceramic article. After solidification of the softened glass/glass-ceramic article the shaping die or dies (4) is or are withdrawn.

Abstract: The method produces a reshaped glass-ceramic article by forced reshaping of a flat green glass part during a ceramicizing process with temporarily lowered viscosity due to crystallization heat. To perform the forced reshaping economically the forced reshaping takes place in a continuous oven for ceramicizing and in an oven section in which the viscosity of the green glass part is temporarily lowered as a result of crystallization heat. An apparatus for performing the process is provided in the continuous oven including different active reshaping devices and/or a hollow mold. The method produces glass-ceramic articles with undamaged surfaces corresponding to surfaces produced during the making of the green glass part (smooth or structured, e.g. knobbed).

Abstract: In the process for partially shaping, a glass/glass ceramic article (5) is held on a planar support plate (1) by suction. The glass/glass ceramic article is heated to soften it, so that it has a viscosity below 106 dPa·s. After the softening one or more shaping dies (4) is or are moved upward through an opening or respective openings (3) in the support plate to form raised regions in the softened glass/glass ceramic article (5). The suction force is produced by a low pressure in a hollow compartment (2) below the support plate (1) and acts on the glass/glass ceramic article (5) by means of a gap (G) formed between each shaping die (4) and the support plate. Additional openings can be provided in the support plate and/or in one or more of the shaping dies to assist in applying the suction force to the glass/glass ceramic article. After solidification of the softened glass/glass-ceramic article the shaping die or dies (4) is or are withdrawn.