Westinghouse Electric Corporation

USA As Represented by Secretary of the Navy

Electric Power Research Institute Incorporated

Douglas M Mattox

Bulent E Yoldas

Robert Tracy Elms

Tapan K Gupta

William G Carlson

Shih M Ho

Laurence H Cadoff

Chester W Dawson

Shih-Ming Ho

Robert B Parsons

A ceramic material for electronic circuit devices is sintered at less than r equal to 1000.degree. C. temperature. A filler material such as quartz and a glassy binder RO--Al.sub.2 O.sub.3 --B.sub.2 O.sub.3 are mixed together along with an appropriate glassy binder prior to firing. RO is drawn from the group of metal oxides MgO, CaO, SrO, BaO, ZnO or CdO and the glassy binders form no more than 40 vol % of the ceramic material. The glassy binder has a suitable viscosity and other properties so that after it is mixed with the quartz filler, sintering occurs at the relatively low temperature. As a consequence, high conductivity conductors made of copper, silver and gold can be appropriately metallized prior to firing. The strength and low dielectric constant of the ceramic material make the material well adapted for ceramic substrates, thick films and the like which are used in VHSIC and VLSI applications.

Glassy binder system for ceramic substrates, thick films and the like

A ceramic material for electronic circuit devices is sintered at less than r equal to 1000.degree. C. temperature. A filler material such as quartz and a glassy binder RO-Al.sub.2 O.sub.3 -B.sub.2 O.sub.3 are mixed together along with an appropriate glassy binder prior to firing. RO is drawn from the group of metal oxides MgO, CaO, SrO, BaO, ZnO or CdO and the glassy binders form no more than 40 vol % of the ceramic material. The glassy binder has a suitable viscosity and other properties so that after it is mixed with the quartz filler, sintering occurs at the relatively low temperature. As a consequence, high conductivity conductors made of copper, silver and gold can be appropriately metallized prior to firing. The strength and low dielectric constant of the ceramic material make the material well adapted for ceramic substrates, thick films and the like which are used in VHSIC and VLSI applications.

A ceramic material for electronic circuit devices is sintered at less than or equal to 1000.degree. C. temperature. A filler material such as quartz and a glassy binder RO--Al.sub.2 O.sub.3 --B.sub.2 O.sub.3 are mixed together along with an appropriate glassy binder prior to firing. RO is drawn from the group of metal oxides MgO, CaO, SrO, BaO, ZnO or CdO and the glassy binders form no more than 40 vol% of the ceramic material. The glassy binder has a suitable viscosity and other properties so that after it is mixed with the quartz filler, sintering occurs at the relatively low temperature. As a consequence, high conductivity conductors made of copper, silver and gold can be appropriately metallized prior to firing. The strength and low dielectric constant of the ceramic material make the material well adapted for ceramic substrates, thick films and the like which are used in VHSIC and VLSI applications.

A non-linear voltage limiting device displaying a particular stability characteristic and designed to eliminate flashover failure across its circumferential edge is disclosed herein along with a specific method of fabrication. The voltage limiting device is characterized by a rising resistive current with time at predetermined temperature and voltage levels and includes a disc-shaped wafer composed primarily of zinc oxide. In accordance with the method disclosed herein, after this wafer is formed and sintered in accordance with prescribed temperature and time requirements, its circumferential edge is provided with an anti-flashover coating which requires curing. Thereafter, the coated wafer is annealed in a way which cures the coating and, at the same time, reduces and preferably minimizes the resistive current rise characteristic referred to above.

Method of fabricating non-linear voltage limiting device

Method for preparing finely divided high purity alumina doped with a small predetermined percentage of magnesia. In the preparation, there is first formed a mixed clear solution of aluminum alkoxide and a small amount of magnesium in the form of alkoxide or water soluble magnesium salt. There is then included with the clear solution a substantial excess of water over that required to completely hydrolyze the alkoxide and there is added thereto a small amount of selected acid which is effective to peptize the resulting slurry. The formed milky slurry is then allowed to become fully peptized to form a clear sol. The clear sol is converted to a finely divided and dried powder either by forming the sol into a gel, which is then dried, and mechanically reduced to a powder status or by spray drying the sol at elevated temperatures which produces the dried powder. Thereafter, the finely divided and dried powder is calcined at a temperature of from about 700.degree. C. to about 900.degree. C., with the crystalline structure of the powder predominately being that of a delta alumina. The preparation of this alumina is very economic and the resulting material is suitable for being isostatically pressed into a tubular form and then sintered to translucent tubular form to a density which closely approaches theoretical.

Economic preparation of alumina suitable for isostatic pressing and

Method for forming conductive, transparent coating such as may be used on the interior surface of a vitreous tubular member. In a carrier gas and exterior to the member to be coated, there is formed a vapor from a material substantially comprising organic tin halide compound having a predetermined condensation temperature and a predetermined decomposition temperature, with the temperature of the carrier gas and the formed vapor maintained between these temperatures. The member to be coated is heated to a temperature greater than the decomposition temperature of the organic tin halide compound and the heated carrier gas and formed vapor are longitudinally flowed through the heated tubular member. Upon contact with the heated tubular member, the vapor breaks down to form the transparent conducting coating. The carrier gas and residual heated vapor are flowed out of the member being coated and are cooled to condense and collect the residual material. There are also provided very high performance fluorine-doped tin oxide coatings.

Method for forming conductive, transparent coating on a substrate

Compact ballast circuit for operating a low-pressure fluorescent lamp wherein line voltage is from about 120% to about 150% of the lamp operating voltage. The compact ballast comprises a positive temperature coefficient (PTC) resistance means and a parallel-connected fixed resistor, both connected in series with the ballasted lamp. Room temperature ohmic resistance of the PTC resistor is from about one-third to about twice the ohmic resistance of the fixed value resistor and the ohmic value of the fixed value resistor is sufficiently low that it will pass sufficient current to sustain the lamp discharge. The voltage drop across the combined ballast resistors is at least about 20% of the voltage across the operating lamp. The PTC resistor is selected to display a curve of resistance versus temperature which breaks and rises sharply after a predetermined operating temperature is achieved and the PTC resistor is associated with a heat sink to cause it to operate at about this transition temperature so that the operating PTC resistor has a relatively constant power dissipation within the range of from about one-third to about one-tenth of the rated lamp power consumption. The power regulation of the circuit is excellent under conditions of varying line voltage.

Compact ballast for fluorescent lamp which provides excellent lamp power

This invention relates to an incandescent lamp having an improved light diffusing coating carried on the internal surface of the lamp envelope and a method for applying the coating. The coating is a mixture of very finely divided, very low-moisture content powders. The powders substantially comprise a mixture of hydrophilic silica and hydrophobic silica. This coating has been found to be very adherent and substantially free from agglomerations of the silica.

Incandescent lamp with improved coating and method

A metal member is coated with or embedded in a high-magnesia glass-ceramic material having the approximate composition of about 60 to 80 weight percent SiO.sub.2, 12 to 20 weight percent Li.sub.2 O, 2 to 14 weight percent MgO, 1.5 to 6 weight percent P.sub.2 O.sub.5, 1 to 7 weight percent of an alkali oxide selected from the group consisting of K.sub.2 O and Na.sub.2 O and their mixtures, 0 to 2 weight percent of a transition metal oxide selected from the group consisting of Co.sub.3 O.sub.4, MnO.sub.2, Fe.sub.2 O.sub.3, V.sub.2 O.sub.5 and WO.sub.3 and their mixtures, 0 to 5 weight percent PbO, 0 to 2 weight percent Al.sub.2 O.sub.3 and 0 to 1 weight percent As.sub.2 O.sub.3.

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Pittsburgh, PA, United States of America

Douglas M Mattox