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US 6,319,429 B1Granted
Oxygen sensitive resistance material
AssigneeDaimlerChrysler AG
InventorsRalf Moos, Wolfgang Menesklou, Hans-Jürgen Schreiner, Karl Heinz Härdtl
Life of this patent
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Abstract
Oxygen sensitive resistance materials for use with oxygen sensors, in particular λ probes are described. These materials are based on the fact that with complex metal oxides it is possible—by adding suitable doping substances—to achieve a negligible temperature dependence of the electric resistance of these materials for different oxygen partial pressures and to preset it to a desired partial pressure value.
Claims44
An oxygen sensor comprising a material composition, comprising one or more complex metal oxides selected from the group consisting of material classes
- 1a) represented by general structure (Sr1−nNn)1−aMaTixXyFezO3−δ
- 1b) represented by general structure (Sr1−nNn)(TixXyFez)1−bM′bO3−δ
- 2a) represented by general structure (Sr1−nNn)(TixXyFez)1−cM″cO3−δand
- 2b) represented by general structure (Sr1−nNn)1−dM′″TixXyFezO3−δ
- wherein:
- Sr is strontium, Ti is titanium, Fe is iron;
- O is oxygen;
- N is a bivalent element or elements selected from the group consisting of barium, calcium, magnesium, zinc, cadmium, mercury, lead, and mixtures thereof;
- X is a tetravalent element selected from the group consisting of silicon, germanium, zirconium, tin, cerium, and hafnium;
- M is a trivalent or tetravalent element or elements selected from the group consisting of a lanthanide element, a mixture of lanthanide elements, yttrium, indium, thallium, and mixtures thereof;
- M′ is a pentavalent or hexavatent element or elements selected from the group consisting of phosphorus, vanadium, arsenic, niobium, antimony, tantalum, molybdenum, tungsten, and mixtures thereof;
- M″ is a bivalent or trivalent element or elements selected from the group consisting of aluminum, scandium, gallium, chromium, manganese, cobalt, nickel, and mixtures thereof;
- M′″ is a monovalent element or elements selected from the group consisting of lithium, sodium, potassium, rubidium, cesium, copper, silver, and mixtures thereof;
- n is greater than or equal to zero, and less than or equal to 1;
- a, b, c, and d are independently greater than zero and less than or equal to 0.5;
- the sum of x+y+z is 1, wherein z is from 0.1 to 0.6, x is from zero to 0.9, and y is from zero to 0.9;
- and
- δ is the oxygen deficit which is to be applied according to the composition in order to establish electrical neutrality of the complex metal oxides.
15 more elements
A material composition, suitable for use in an oxygen sensor, comprising one or more complex metal oxides selected from the group consisting of material classes
- 1a) represented by general structure (Sr1−nNn)1−aMaTixXyFezO3−δ
- 1b) represented by general structure (Sr1−nNn)(TixXyFez)1−bM′bO3−δ
- 2a) represented by general structure (Sr1−nNn)(TixXyFez)1−cM″cO3−δand
- 2b) represented by general structure (Sr1−nNn)1−dM′″dTixXyFezO3−δ
- wherein:
- Sr is strontium, Ti is titanium, Fe is iron;
- O is oxygen;
- N is a bivalent element or elements selected from the group consisting of barium, calcium, magnesium, zinc, cadmium, mercury, lead, and mixtures thereof;
- X is a tetravalent element selected from the group consisting of silicon, germanium, zirconium, tin, cerium, and hafnium;
- M is a trivalent or tetravalent element or elements selected from the group consisting of a lanthanide element, a mixture of lanthanide elements, yttrium, indium, thallium, and mixtures thereof;
- M′ is a pentavalent or hexavalent element or elements selected from the group consisting of phosphorus, vanadium, arsenic, niobium, antimony, tantalum, molybdenum, tungsten, and mixtures thereof;
- M″ is a bivalent or trivalent element or elements selected from the group consisting of aluminum, scandium, gallium, chromium, manganese, cobalt, nickel, and mixtures thereof;
- M′″ is a monovalent element or elements selected from the group consisting of lithium, sodium, potassium, rubidium, cesium, copper, silver, and mixtures thereof;
- n is greater than or equal to zero, and less than or equal to 1;
- a, b, c, and d are independently greater than zero and less than or equal to 0.5;
- the sum of x+y+z is 1, wherein z is from 0.1 to 0.6, x is from zero to 0.9, and y is from zero to 0.9;
- and
- δ is the oxygen deficit which is to be applied according to the composition in order to establish electrical neutrality of the complex metal oxides.
15 more elements
A method for designing an oxygen sensor based on complex metal oxides with the general formula
- (Sr1−nNn)(Ti1−zFez)O3−δ
- by changing the position of the working point of the sensor toward a higher oxygen potential,
- wherein
- Sr is strontium, Ti is titanium, Fe is iron;
- N is a bivalent element selected from the group consisting of barium (Ba), calcium (Ca), magnesium (Mg), zinc (Zn), cadmium (Cd), mercury (Hg), lead (Pb) and mixtures thereof;
- n is greater than zero and less than one;
- z is greater than equal to 0.1 and less than or equal to 0.6;
- and
- δ is the oxygen deficit, which, depending on the respective composition, occurs in accordance with the electron neutrality condition, the method comprising at least one of the steps of:
- 1) partially replacing the bivalent (Sr1−nNn) by trivalernt and/or tetravalent M where M is selected from the group consisting of a lanthanide element, yttrium, indium, thallium, and mixtures thereof;
- and
- 2) partially replacing quadrivalent (Ti1−zFez) by pentavalent and/or hexavalent M′, where M′ is selected from the group consisting of phosphorus (P), vanadium (V), arsenic (As), niobium (Nb), antimony (Sb), tantalum (Ta), molybdenum (Mo), tungsten (W), and mixtures thereof.
9 more elements
A method for designing an oxygen sensor based on complex metal oxides with the general formula
- (Sr1−nNn)(Ti1−zFez)O3−δ
- by changing the position of the working point of the sensor toward a lower oxygen potential,
- wherein
- Sr is strontium, Ti is titanium, Fe is iron;
- N is a bivalent element selected from the group consisting of barium (Ba), calcium (Ca), magnesium (Mg), zinc (Zn), cadmium (Cd), mercury (Hg), lead (Pb), and mixtures thereof;
- n is greater than zero and less than one;
- z is greater than or equal to 0.1 and less than or equal to 0.6;
- and
- δ is the oxygen deficit, which, depending on the respective composition, occurs in accordance with the electron neutrality condition, the method comprising at least one of the steps of
- 1) partially replacing tetravalent (Ti1−zFez) by trivalent and/or bivalent M″, where M″ is selected from the group consisting of aluminum (Al), scandium (Sc), gallium (Ga), chromium (Cr), manganese (Mn), cobalt (Co), nickel (Ni), and mixtures thereof;
- and
- 2) partially replacing bivalent (Sr1−nNn) by monovalent M′″, where M′″ is selected from the group consisting of lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), copper (Cu), silver (Ag), and mixtures thereof.
9 more elements
Dependencies are inferred from the claim text.