Unlock instant, AI-driven research and patent intelligence for your innovation.

Ceramic discharge vessel with expanded reaction-bonded aluminum oxide member

A ceramic discharge tube, alumina technology, applied in the field of discharge tubes including a sapphire tube body, can solve the problems of high heat loss, high cost, high rupture rate and the like

Inactive Publication Date: 2006-07-05
OSRAM SYLVANIA INC
View PDF1 Cites 2 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the high heat capacity of the PCA cap results in high heat loss from the surface of the PCA cap via radiation and induces severe thermal stress that can lead to a high cracking rate
Additionally, the cost of the sapphire-PCA construction is relatively high compared to competing technologies
Unfortunately, sapphire tubes with frit-sealed PCA plugs are not suitable candidates because frits in this type of construction are in close proximity to higher temperature regions and would therefore be filled with corrosive metal halides Attack more quickly, this filler can cause lamps to fail earlier

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Ceramic discharge vessel with expanded reaction-bonded aluminum oxide member
  • Ceramic discharge vessel with expanded reaction-bonded aluminum oxide member
  • Ceramic discharge vessel with expanded reaction-bonded aluminum oxide member

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0017] In order to better understand the present invention and other and further objects, advantages and performance thereof, the following content and appended claims are described in conjunction with the above-mentioned illustrations.

[0018] After completing a reactive bonding cycle for RBAO ceramics, the general equation for the total dimensional change (S) is Equation (1) below:

[0019] (1) S=[(1+∑υ i V i )(ρ 0 / ρ) / (1+0.28fV Al )] 1 / 3 -1

[0020] Among them, υ i is the corresponding oxide (e.g., υ Al =0.28, υ Zr =0.49, υ Ti =0.76, υ Cr =1.02) related volume expansion, V i is metal (including V Al ) or the volume fraction of the ceramic phase added to the initial powder mixture, f is the oxidation fraction of Al at the time of pulverization, ρ 0 and ρ are the green and final densities, respectively. Equation (1) shows that a higher volume fraction of Al and a higher green density can be obtained for Al / Al 2 o 3 The resulting expansion (rather than contract...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

A ceramic discharge vessel is provided wherein the discharge vessel has a ceramic body and at least one expanded reaction-bonded aluminum oxide member hermetically sealed to the ceramic body. The method of making the discharge vessel includes (a) forming a ceramic body; (b) forming a reaction-bonded aluminum oxide member in a green state by compacting a mixture of aluminum metal and aluminum oxide powders; (c) assembling the ceramic body and the reaction-bonded aluminum oxide member in the green state to form an assembly; and (d) reaction sintering the assembly to cause the reaction-bonded aluminum oxide member to expand and form a hermetic seal with the ceramic body.

Description

technical field [0001] The present invention relates to ceramic discharge tubes, and more particularly to discharge tubes comprising a sapphire tube body for high illumination discharge applications. Background technique [0002] Ceramic discharge tubes are commonly used in high-intensity discharge (HID) lamps such as high-pressure sodium lamps (HPS), high-pressure mercury lamps, and metal halide lamps. These discharge vessels are typically formed from multiple ceramic pieces that are co-sintered to form a seal between components that do not use frit material. This technique relies on differential shrinkage of ceramic pieces to create an interference fit between the parts. The preferred ceramic for HID lamp applications is polycrystalline alumina (PCA), although other ceramics such as sapphire, yttrium aluminum garnet, aluminum nitride, and aluminum oxynitride can also be used. [0003] In addition to being limited to a straight shape defined by crystal growth techniques, ...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(China)
IPC IPC(8): H01J61/36H01J9/40
CPCH01J9/266H01J61/302H01J61/30H01J61/36
Inventor K·京特R·许廷格尔W·P·拉帕托维奇G·C·魏
Owner OSRAM SYLVANIA INC