METHOD FOR FORMING OPAQUE QUARTZ GLASS COMPONENTS

A method of forming an opaque quartz glass component is provided. The method includes (a) providing a starting preform made of quartz glass; (b) heating at least a portion of the starting preform to a predetermined temperature at which the quartz glass of the starting preform has a viscosity in a range of 10E2 to 10E12 poise; and (c) deforming at least a portion of the heated preform at the predetermined temperature to change a shape and/or dimension(s) of the heated perform in order to form the opaque quartz glass component. The starting preform and the heated preform have respective densities of at least 2.15 g/cmand at least 2.10 g/cm. The starting perform and the opaque quartz glass component have respective direct spectral transmissions of approximately 0.1-1% and 0.2-3% in the wavelength range of λ=190 nm to λ=4990 nm at a wall thickness of 3 mm and a diffuse reflectance of at least 60% in a wavelength range of λ=190 nm to λ=2500 nm. 1. A method of forming an opaque quartz glass component , the method comprising:{'sup': '3', '(a) providing a starting preform made of quartz glass, the starting perform having a direct spectral transmission of approximately 0.1 to 1% in a wavelength range of λ=190 nm to λ=4990 nm at a wall thickness of 3 mm and a diffuse reflectance of at least 60% in a wavelength range of λ=190 nm to λ=2500 nm and a density of at least 2.15 g/cm, at least 80% of pores of the starting preform having a maximum pore dimension of between 1 and 20 μm;'}{'sup': '3', '(b) heating at least a portion of the starting preform to a predetermined temperature at which the quartz glass has a viscosity in a range of 10E2 to 10E12 poise and a density of at least 2.10 g/cm, at least 80% of pores of the heated preform having a maximum pore dimension of between 1 and 45 μm; and'}(c) deforming at least a portion of the heated preform at the predetermined temperature to change at least one of a shape and dimension(s) of the heated preform in order to form the opaque ...

Method of forming components from opaque quartz glass

Verfahren zum Formen einer Komponente aus opakem Quarzglas, wobei das Verfahren Folgendes umfasst:(a) Bereitstellen eines aus Quarzglas bestehenden Ausgangs-Vorformlings, wobei der Ausgangs-Vorformling eine direkte spektrale Transmission von 0,1 bis 1 % in einem Wellenlängenbereich von λ=190 nm bis λ=4990 nm bei einer Wanddicke von 3 mm und eine diffuse Reflexion von mindestens 60 % in einem Wellenlängenbereich von λ=190 nm bis λ=2500 nm und eine Dichte von mindestens 2,15 g/cmaufweist, wobei mindestens 80 % der Poren des Ausgangs-Vorformlings eine maximale Porenabmessung von 1 bis 20 µm aufweisen;(b) Erhitzen mindestens eines Abschnitts des Ausgangs-Vorformlings auf eine vorgegebene Temperatur, bei welcher das Quarzglas eine Viskosität im Bereich von 10bis 10dPa·s und eine Dichte von mindestens 2,10 g/cmaufweist, wobei mindestens 80 % der Poren des erhitzten Ausgangs-Vorformlings eine maximale Porenabmessung von 1 bis 45 µm aufweisen; und(c) Entformen mindestens eines Abschnitts des erhitzten Ausgangs-Vorformlings bei der vorgegebenen Temperatur, um Gestalt und/oder Abmessung(en) des erhitzten Ausgangs-Vorformlings unter Bildung der Komponente aus opakem Quarzglas zu verändern, wobei die Komponente aus opakem Quarzglas eine direkte spektrale Transmission von 0,2 bis 3 % in einem Wellenlängenbereich von λ=190 nm bis λ=4990 nm bei einer Wanddicke von 3 mm und eine diffuse Reflexion von mindestens 60 % in einem Wellenlängenbereich von λ=190 nm bis λ=2500 nm aufweist. A method of forming an opaque quartz glass component, the method comprising: (a) providing a starting quartz glass preform, wherein the starting preform has a direct spectral transmission of 0.1 to 1% in a wavelength range of λ = 190 nm to λ = 4990 nm with a wall thickness of 3 mm and a diffuse reflection of at least 60% in a wavelength range of λ = 190 nm to λ = 2500 nm and a density of at least 2.15 g / cm, wherein at least 80% of the (B) heating at least a portion of the starting preform to a ...

Exhaust gas sensor

Disclosed herein is a gas sensor having a small amount of lead oxide incorporated into an inner electrode and an outer electrode, and a method for depositing the lead oxide. The lead oxide is applied in an amount sufficient to effectuate consistent performance during sensor break-in. Lead oxide is transferred to the electrodes of the sensor element during the fabrication process by exposing the sensor element to glass having a known lead content during a heating step. Lead oxide from the glass is vaporized and deposited on the electrodes in the form of lead oxide. The deposited lead oxide is incorporated into the electrodes of the sensor element. The lead oxide reduces performance irregularities thereby improving performance during the initial use of the gas sensor.

Chemical plating method, electrolytic cell and automotive oxygen sensor using it

An automotive lambda oxygen sensor is formed by electroless plating of a thin, catalytically active, conductive electrode uniformly on the outer surface of a zirconia thimble. The process includes forming a pristine zirconia solid electrolyte thimble and drilling out a cylindrical cavity in it. A porous outer surface suitable for producing crystallization sites is formed by dipping the unfired thimble in a zirconia slurry containing spray-dried microspheres and firing the coated thimble to densify the thimble and the microspheres and to produce cavities on the surface of the thimble. An inner platinum electrode is formed by conventional conductive ink painting on the axial cavity of the sensor, and the sensor is again fired. The surface is activated by immersion in an acetone chloroplatinic acid bath to form multiple crystallization points, heat treated, then plated in an electroless platinum bath to a desired thickness. After plating, the sensor is heat treated and a conventional spinel glaze coat is flame sprayed over the sensor. The process produces sensors which consistently provide rapid response times and stable operation.

Chemical plating method, electrolytic cell and automotive oxygen sensor using it

A sintering device with temperature gradient control

A process for the preparation of a ceramic body, comprising the steps: a. providing a plurality of particles; b. providing a device that comprises a sintering chamber (013) bordered by a die (006); c. introducing the particles into the sintering chamber; d. applying a pressure P in the range from 1 MPa to 80 MPa to the plurality of particles in the sintering chamber to obtain the ceramic body, wherein a temperature in the sintering chamber, during preparation of the ceramic body, is controlled so that the temperature at a centre of the sintering chamber is lower than the temperature at an interior surface (006) of the die.

A sintering device having a die lining of increased thickness

The invention relates in general to sintering under pressure and with electrical current, often termed spark plasma sintering (SPS). Particular aspects of the invention are directed to a sintering device, a sintering process, a ceramic body product, an assembly comprising the ceramic body and the use of a graphite layer in a sintering process. The invention relates to a device having a sintering chamber (013), the sintering chamber being bordered by the following device parts: i. a first punch surface (004) of a first punch (003); ii. a second punch surface (007) of a second punch (008); and iii. an interior surface (005) of a die (006); wherein: the punches are adapted and arranged to apply a pressure of at least 1 MPa along a compression axis (011) to a target in the sintering chamber; the first punch and the second punch are connected to an electrical power source (012) adapted and arranged to provide a current of at least 5 kA; the first and second punches comprise at least 50 wt. % carbon, based on the total weight of the punch; the sintering chamber has a cross-sectional width W perpendicular to the compression axis of at least 300 mm; wherein a layer δ of a carbon material C δ is present at at least part of the interior surface of the die, the layer δ having a mean thickness D δ determined over the interior surface of the die, wherein D δ is in the range from 1.1 to 8 mm.

A sintering device having low surface roughness

A device having a sintering chamber (013), the sintering chamber (013) being bordered by the following device parts: i. a first punch surface (004) of a first punch (003); ii. a second punch surface (007) of a second punch (008); and iii. an interior surface (005) of a die (006); wherein: the punches (003, 008) are adapted and arranged to apply a pressure of at least 1 MPa along a compression axis (011) to a target in the sintering chamber (013); the first punch (003) and the second punch (008) are connected to an electrical power source (012) adapted and arranged to provide a current of at least 10 kA; the first and second punches (003, 008) comprise at least 50 wt. % carbon, based on the total weight of the punch (003, 008); the sintering chamber (013) has a cross-sectional width W perpendicular to the compression axis (011) of at least 300 mm; wherein the die has a surface portion X at least 5 cm 2 in area, wherein the surface portion χ is located on the interior surface of the die and wherein the surface portion χ has a mean surface roughness (Sa) in the range from 1 µm to 8 µm.

Method for forming opaque quartz glass components

A method of forming an opaque quartz glass component is provided. The method includes (a) providing a starting preform made of quartz glass; (b) heating at least a portion of the starting preform to a predetermined temperature at which the quartz glass of the starting preform has a viscosity in a range of 10E2 to 10E12 poise; and (c) deforming at least a portion of the heated preform at the predetermined temperature to change a shape and/or dimension(s) of the heated perform in order to form the opaque quartz glass component. The starting preform and the heated preform have respective densities of at least 2.15 g/cm 3 and at least 2.10 g/cm 3 . The starting perform and the opaque quartz glass component have respective direct spectral transmissions of approximately 0.1-1% and 0.2-3% in the wavelength range of λ=190 nm to λ=4990 nm at a wall thickness of 3 mm and a diffuse reflectance of at least 60% in a wavelength range of λ=190 nm to λ=2500 nm.