# US 7,744,736 B2 · Method of manufacturing a reference electrode > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,744,736 B2 - Document ID: US7744736B2 - Status: Granted - Kind: B2 - Application number: 11/164,944 - Filed: 2005-12-12 - Published: 2007-01-11 - Granted: 2010-06-29 - Earliest claimed: 2004-06-25 - Assignees: Mettler-Toledo AG - Inventors: Sascha Murer - Web page: https://patentgrep.com/patent/US7744736B2 ## CPC - C04B 41/009: {characterised by the material treated} - C04B 41/4537: {by the sol-gel process} - C04B 41/81: Coating or impregnation - G01N 27/401: Salt-bridge leaks; Liquid junctions - C04B 2111/00801: {Membranes; Diaphragms} - Y10T 428/131: Glass, ceramic, or sintered, fused, fired, or calcined metal oxide or metal carbide containing [e.g., porcelain, brick, cement, etc.] - Y10T 428/1376: Foam or porous material containing - Y10T 428/249967: Inorganic matrix in void-containing component - C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A method of manufacturing a reference electrode which has a shaft into which a diaphragm body of a porous ceramic is incorporated is comprised of the following method steps: Impregnating the ceramic with a lyogel precursor prior to incorporating the ceramic body into the shaft, and subsequently transforming the lyogel precursor into a lyogel, from which the solvent is removed through a drying process. A reference electrode has a shaft that is filled with electrolyte, and a diaphragm body formed of a porous ceramic and containing a system of hollow spaces is incorporated into the wall of the shaft. The system of hollow spaces is filled at least partially with a material that is formed of a lyogel by drying and has at least one component that corresponds to the ceramic material. ## Claims ### Claim 1 A method of manufacturing a reference electrode, the reference electrode having a shaft into which a diaphragm body of a porous ceramic is incorporated, the method comprising the steps of: providing a porous ceramic body; impregnating the ceramic body with a lyogel precursor; transforming the lyogel precursor into a lyogel; removing solvent from the impregnation step by drying, to form the diaphragm body; and incorporating the diaphragm body into the shaft. ### Claim 2 (depends on 1) The method of claim 1, wherein the drying process transforms the lyogel into an aerogel. ### Claim 3 (depends on 2) The method of claim 2, wherein the porous ceramic comprises zirconia. ### Claim 4 (depends on 3) The method of claim 3, wherein the porous ceramic further comprises at least one of calcium oxide, magnesium oxide and yttrium oxide as a stabilizing additive. ### Claim 5 (depends on 4) The method of claim 4, wherein the lyogel precursor is an aqueous suspension of nano particles selected from the group consisting of zirconia, zirconia/calcia, zirconia/magnesia, and zirconia/yttria. ### Claim 6 (depends on 4) The method of claim 4, wherein the lyogel precursor is selected from a group consisting of an aqueous zirconium solution, an organic zirconyl compound and a zirconium compound in an organic solvent. ### Claim 7 (depends on 4) The method of claim 4, wherein the step of transforming the lyogel precursor into the lyogel occurs by a change of the pH value. ### Claim 8 (depends on 7) The method of claim 7, wherein a base is used to change the pH value. ### Claim 9 (depends on 8) The method of claim 8, wherein the base is an ammonia solution. ### Claim 10 (depends on 8) The method of claim 8, wherein the base is a volatile organic amine. ### Claim 11 (depends on 8) The method of claim 8, wherein the base is used in a gaseous state. ### Claim 12 (depends on 8) The method of claim 8, wherein the base is selected from the group consisting of isopropylamine, propylamine, tetramethyl amino methane, and triethylamine. ### Claim 13 (depends on 1) The method of claim 1, wherein the lyogel precursor used to impregnate the porous ceramic includes a gelating agent. ### Claim 14 (depends on 1) The method of claim 1, wherein the porous ceramic comprises zirconia. ### Claim 15 (depends on 14) The method of claim 14, wherein the porous ceramic further comprises at least one of calcium oxide, magnesium oxide and yttrium oxide as a stabilizing additive. ### Claim 16 (depends on 1) The method of claim 1, wherein the lyogel precursor is an aqueous suspension of nano particles selected from the group consisting of zirconia, zirconia/calcia, zirconia/magnesia, and zirconia/yttria. ### Claim 17 (depends on 1) The method of claim 1, wherein the lyogel precursor is selected from a group consisting of an aqueous zirconium solution, an organic zirconyl compound and a zirconium compound in an organic solvent. ### Claim 18 (depends on 1) The method of claim 1, wherein the step of transforming the lyogel precursor into the lyogel occurs by a change of the pH value. ### Claim 19 (depends on 18) The method of claim 18, wherein a base is used to change the pH value. ### Claim 20 (depends on 19) The method of claim 19, wherein the base is an ammonia solution. ### Claim 21 (depends on 19) The method of claim 19, wherein the base is a volatile organic amine. ### Claim 22 (depends on 19) The method of claim 19, wherein the base is selected from the group consisting of isopropylamine, propylamine, tetramethyl amino methane, and triethylamine. ### Claim 23 (depends on 19) The method of claim 19, wherein the base is used in a gaseous state. ### Claim 24 A reference electrode comprising: a shaft adapted to be filled with electrolyte, a wall of the shaft having a diaphragm body incorporated therein, the diaphragm body being formed of a porous ceramic and providing a system of hollow spaces wherein the system of hollow spaces is filled at least partially with a material formed of a lyogel by drying, the material comprising at least one component that corresponds to the ceramic material. ### Claim 25 (depends on 24) The reference electrode according to claim 24, wherein the ceramic is formed of zirconia. ### Claim 26 (depends on 25) The reference electrode of claim 25, wherein the lyogel is selected from at least one of zirconia, zirconia/calcia, zirconia/magnesia, and zirconia/yttria. ### Claim 27 (depends on 24) The reference electrode of claim 24, wherein the lyogel is selected from at least one of zirconia, zirconia/calcia, zirconia/magnesia, and zirconia/yttria.