Heavy metal fluoride glasses are made by a process that requires high purity fluoride constituent compounds, some of which are further refined by sublimation. Handling occurs in a protective atmosphere such as argon. The charge is placed in a sealed modified optical growth furnace having the ability of atmosphere control, heat control and position control of the charge. The charge is firstly raised to its fusion temperature, then to an admixture temperature, and finally to a higher temperature. The charge is immediately removed from the heating source and quickly cooled through the critical crystallization region. The total heating and cooling time being about one to two hours. The resulting glass ingot is partially annealed. The HMFG of (Zr or Hf)F 4 -BaF 2 -LaF 3 -AlF 2 consistently exhibits low levels of both light scattering and bulk OH contact, along with very reproducible hardness, thermal parameters, and UV and IR edge absorption behavior.

Process for making bulk heavy metal fluoride glasses

An apparatus for drawing a dielectric optical waveguide having minimal attenuation characteristics comprises a double crucible in a closed atmosphere container with glass rod supply means and atmosphere supply means.

Drawing dielectric optical waveguides

A method for fabricating the hermetic electrical feedthrough. The method comprises providing a ceramic sheet having an upper surface and a lower surface, forming at least one via hole in said ceramic sheet extending from said upper surface to said lower surface, inserting a conductive thickfilm paste into said via hole, laminating the ceramic sheet with paste filled via hole between an upper ceramic sheet and a lower ceramic sheet to form a laminated ceramic substrate, firing the laminated ceramic substrate to a temperature to sinter the laminated ceramic substrate and cause the paste filled via hole to form metalized via and cause the laminated ceramic substrate to form a hermetic seal around said metalized via, and removing the upper ceramic sheet and the lower ceramic sheet material from the fired laminated ceramic substrate to expose an upper and a lower surface of the metalized via.

Method for Providing Hermetic Electrical Feedthrough

A method of forming an oxide glass including heating a glass melt having a -OH concentration of at least about 0.35 in a vessel comprising a metal selected from the group consisting of platinum, molybdenum, palladium, rhodium, and alloys thereof, there being an interface present between the vessel and the glass, and controlling a partial pressure of hydrogen in an atmosphere in contact with an outside surface of the vessel in an amount such that hydrogen permeation blisters form in a region of the glass adjacent the glass-vessel interface.

Method of fining glass

A substantially-isolated/controlled, limited-volume, gas-filled space (e.g., 113b) is formed over at least one free (open) surface of flowing molten glass in a manufacturing line used to produce glass sheets (137), e.g., a manufacturing line employing the fusion process to produce glass sheets suitable for use as substrates for liquid crystal displays. At least a portion of the space comprises a platinum-group metal, e.g., a platinum-rhodium alloy, which can serve as a source of platinum-group condensate defects. The use of the substantially-isolated/controlled, limited-volume, gas filled space substantially reduces the level of such platinum-group condensate defects in the glass sheets, e.g., by more than 50%.

Methods and apparatus for reducing platinum-group defects in sheet glass

This invention provides methods for melting glass laser compositions to provide glass laser rods with a minimum of noble metal inclusions and a minimum of dissolved noble metal content. The process comprises melting the laser glass in a platinum container in a controlled reducing atmosphere using a buffered gas mixture, such as CO2/CO in which the partial pressure of oxygen is at a minimum level that is equivalent to a range of about 10 8.6 to 10 38 atmospheres for a temperature range of about 981 DEG F. to 3,321 DEG F. for a silicate glass. A method also is provided for melting glass to make high-quality glass articles in a noble metal container or a lined container in which the container or the liner therefore has at least 50% by weight of platinum without any attack on the container by the unwanted formation of a noble metal alloy from the glass melt during melting. The method comprises heating molten glass in the platinum container, providing a reducing atmosphere in which the partial pressure of oxygen is no greater than about 10 3 atmospheres with a buffered gas mixture, and controlling the reducing atmosphere by maintaining the partial pressure of oxygen above the amount at which oxides of an element such as SiO2, Li2O and Na2O are reduced to the element such as Si, Li or Na, so that the element does not react with the platinum metal to form a platinum-Si alloy.

Earl D Dietz

Papers

Method of melting glass in a platinum container in a controlled atmosphere