US5318725A
Expired / Lapsed
US
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Electroceramics and process for making the same
Assignee: American Superconductor Corp
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Filing: 1993-09-01
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Granted: 1994-06-07
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Expires: 2013-09-01
Abstract
Abstract Principal types of dielectric ceramics include capacitors, and piezoelectric electroptic and optical ceramics. The former are typically barium titanates, the latter, so-called PZT or PLZT materials. The ceramic materials are made by forming an alloy including the metallic elements in substantially stoichiometric proportions, and then oxidizing the alloy to produce the ceramic. In preferred embodiments, the alloy includes a dopant that is encapsulated in a noble metal, preferably silver. Preferred dielectrics are made by making a multi-layer structure in which a plurality of alloy layers (typically less than 20, and preferably less than 5, microns thick) are separated by conductive layers (preferably a noble metal), and then oxidizing the overall structure to form a multi-layer capacitor.
Inventors
- 👤 Kenneth H. Sandhage
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-10 02:36
CPC Classifications
H; H10; H10N; H10N30/00; H10N30/01; H10N30/09; H10N30/093; C; C04; C04B; C04B35/00; C04B35/01; C04B35/46; C04B35/462; C04B35/465; C04B35/468; C04B35/4682; C04B35/4684; C04B35/48; C04B35/49; C04B35/491; C04B35/622; C04B35/64; C04B35/65; H10N30/05; H10N30/80; H10N30/85; H10N30/853; H10N30/8536; H10N30/8548; H10N30/8554
Claims Analysis
Total Claims: 35
Claim 1
Independent Claim
82 words
A method of making a multi-layer dielectric, piezoelectric, electro-optic, or optical ceramic oxide device comprising the steps of: a. combining metallic elements in substantially the stoichiometric proportions needed to form said oxide to form an alloy; b. forming a multi-layer structure including a plurality of layers of said alloy with a conductive layer between each pair of adjacent layers of said alloy; and, c. oxidizing said layers of said alloy to transform said layers of said alloy into layers of said oxide.
Claim 2
Independent Claim
82 words
A method of making a multi-layer dielectric, piezoelectric, electro-optic, or optical ceramic oxide device comprising the steps of: a. combining metallic elements in substantially the stoichiometric proportions needed to form said oxide to form an alloy; b. forming a multi-layer structure including a plurality of layers of said alloy with a conductive layer between each pair of adjacent layers of said alloy; and, c. oxidizing said layers of said alloy to transform said layers of said alloy into layers of said oxide.
Claim 3
Dependent Claim
24 words
The method of claim 1 wherein said elements combined in said stoichiometric proportions include titanium and either (a) barium or (b) lead and zirconium.
Claim 4
Dependent Claim
17 words
The method of claim 2 wherein said elements combined in said stoichiometric proportions include titanium and barium.
Claim 5
Dependent Claim
18 words
The method of claim 2 wherein the elements combined in said stoichiometric proportions include titanium, lead, and zirconium.
Claim 6
Dependent Claim
35 words
The method of claim 1 wherein said elements combined in said stoichiometric proportions include an element selected from the group consisting of column 1-A elements, column 2-A elements, column IV-A elements and column V-A elements.
Claim 7
Dependent Claim
47 words
The method of claim 1 wherein said elements combined in said stoichiometric proportions include a first element selected from the group consisting of column 1-A elements and column 2-A elements, and a second element selected from the group consisting of column IV-A elements and column V-A elements.
Claim 8
Dependent Claim
37 words
The method of claim 1 wherein said elements combined in said stoichiometric proportions include titanium and an element selected from the group consisting of lanthanum, barium, strontium, calcium, lead, niobium, magnesium, lithium, neodymium, bismuth, tin, and zirconium.
Claim 9
Dependent Claim
39 words
The method of claim 1 wherein said elements combined in said stoichiometric proportions include niobium and an element selected from the group consisting of barium, magnesium, lead, zinc, iron, tungsten, scandium, bismuth, nickel, potassium, germanium, lithium, strontium, and titanium.
Claim 10
Dependent Claim
32 words
The method of claim 1 wherein said elements combined in said stoichiometric proportions include tantalum and an element selected from the group consisting of scandium, lead, magnesium, barium, tin, zirconium and iron.
Claim 11
Dependent Claim
31 words
The method of claim 1 wherein said elements combined in said stoichiometric proportions include tungsten and an element selected from the group consisting of nickel, lead, scandium, magnesium, lithium and iron.
Claim 12
Dependent Claim
28 words
The method of claim 1 wherein said elements combined in said stoichiometric proportions include iron and an element selected from the group consisting of barium, calcium and strontium.
Claim 13
Dependent Claim
30 words
The method of claim 1 wherein said elements combined in said stoichiometric proportions include zinc and an element selected from the group consisting of bismuth, antimony, cobalt, manganese and chromium.
Claim 14
Dependent Claim
26 words
The method of claim 1 wherein said elements combined in said stoichiometric proportions include a dopant present in an amount not greater than 5 mole percent.
Claim 15
Dependent Claim
24 words
The method of claim 1 wherein said metallic elements include titanium and barium in substantially 1:1 stoichiometric proportions, and said oxide is barium titanate.
Claim 16
Dependent Claim
22 words
The method of claim 14 wherein the thickness of each of said layers of said alloy is less than about 20 microns.
Claim 17
Dependent Claim
14 words
The method of claim 15 wherein said thickness is less than about 5 microns.
Claim 18
Dependent Claim
13 words
The method of claim 1 wherein said conductive layer is a noble metal.
Claim 19
Dependent Claim
11 words
The method of claim 17 wherein said conductive layer is silver.
Claim 20
Dependent Claim
20 words
The method of claim 1 including the step of combining said metallic elements with a dopant prior to said oxidizing.
Claim 21
Dependent Claim
19 words
The method of claim 1 wherein said oxidizing is accomplished at a temperature not more than about 1200° C.
Claim 22
Dependent Claim
15 words
The method of claim 1 wherein said temperature is not more than about 900° C.
Claim 23
Dependent Claim
21 words
The method of claim 1 including the step of surrounding said multi-layer structure with a noble metal prior to said oxidizing.
Claim 24
Dependent Claim
11 words
The method of claim 22 wherein said noble metal is silver.
Claim 25
Dependent Claim
12 words
A ceramic oxide material prepared according to the method of claim 1.
Claim 26
Dependent Claim
27 words
The method of claim 1 wherein said step of combining includes a process selected from the group consisting of mechanical alloying, melt alloying, vapor deposition and sputtering.
Claim 27
Dependent Claim
35 words
The method of claim 1 including the steps of placing said combined metallic elements into a tube of a noble metal, sealing said tube, and mechanically deforming said sealed tube to reduce the cross-section thereof.
Claim 28
Dependent Claim
36 words
The method of claim 26 including the step of forming a multi-layer structure including a plurality of lengths of mechanically deformed and sealed tube, and thereafter mechanically deforming said multi-layer structure to form said multi-layer structure.
Claim 29
Dependent Claim
23 words
The method of claim 26 wherein said mechanically deformed and sealed tube is generally circular in cross-section and said multi-layer structure is multi-filamentary.
Claim 30
Dependent Claim
36 words
The method of claim 26 wherein said sealed tube is mechanically deformed to produce a tape of generally rectangular cross-section, and lengths of said tape are stacked to provide a multi-layer structure of generally rectangular cross-section.
Claim 31
Dependent Claim
20 words
The method of claim 1 including the steps of depositing said layers onto a substrate by a vapor state process.
Claim 32
Dependent Claim
22 words
The method of claim 30 wherein said vapor state process is selected from the group consisting of evaporation, sputtering, and laser ablation.
Claim 33
Dependent Claim
32 words
The method of claim 1 wherein said step of oxidizing is conducted with an oxidizing atmosphere of a solid, liquid, or gaseous phase, or a combination of solid, liquid, or gaseous phases.
Claim 34
Dependent Claim
19 words
The method of claim 1 wherein said step of oxidizing is conducted with an applied potential in electric field.
Claim 35
Dependent Claim
19 words
The method of claim 1 wherein said step of oxidizing includes oxidation of solid, liquid, and gaseous metal alloys.
References Cited (Backward Citations)
US5102864A
Cited
JPS6417318A
Cited
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