SENSOR ELEMENT OF NOx SENSOR

• Main Authors: WATANABE YUSUKE, IWAI SHIHO, SEKIYA TAKAYUKI
• Format: Patent
• Language: English; Japanese
• Published: 03.08.2022
• Subjects: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; MEASURING; PHYSICS; TESTING

To suppress a decline in sensitivity of an NOx sensor attributable to the oxidation of a measurement electrode.SOLUTION: A sensor element comprises: a base unit composed of a solid electrolyte of oxygen ion conduction type; at least one internal void into which gas to be measured is introduced; an internal electrode arranged facing the internal void; and at least one pump cell composed of an out-of-void pump electrode arranged at a point other than the internal void and a portion of the base unit existing between two electrodes. The internal electrode is composed of noble metal, a solid electrolyte, and a pore. A degree of area boundary variation which is a degree of variation in a thickness direction of the element at a boundary of the internal electrode between a first area composed of the base unit or the solid electrolyte continuous from the base unit and a second area occupied by the noble metal and pore is 0.5 μm or more and 6.5 μm or less.SELECTED DRAWING: Figure 2 【課題】測定電極の酸化に起因したＮＯｘセンサの感度低下を抑制する。【解決手段】センサ素子が、酸素イオン伝導性の固体電解質を構成材料とする基体部と、被測定ガスが導入される少なくとも１つの内部空所と、当該内部空所に面して配置されてなる内部電極と、当該内部空所以外の箇所に配置された空所外ポンプ電極と、基体部のうち両電極の間に存在する部分とから構成される少なくとも１つのポンプセルと、を備え、内部電極が、貴金属と固体電解質と気孔とからなり、内部電極における、基体部または基体部から連続した固体電解質からなる第１領域と貴金属および気孔が占める第２領域との境界の、素子厚み方向におけるばらつき度である領域境界ばらつき度が、０．５μｍ以上６．５μｍ以下である、ようにした。【選択図】図２