Brevet : EP3306762 - BOUGIE D'ALLUMAGE

Titre

BOUGIE D'ALLUMAGE

N° et date de publication de la demande

EP3306762 - 11/04/2018

Type de la demande

A1

N° et date de dépôt

EP16799540.6 - 16/05/2016

N° et date de priorité

JP2015108261 - 28/05/2015

Famille de brevets

US2018166863A1 ; KR20170141232A ; EP3306762A1 ; WO2016189826A1 ; JP2016225053A ; CN107615605A

Abrégé

An object of the present invention is to provide a spark plug having excellent durability in which when the spark plug is used in a combination of a high-temperature environment and a harsh heating/cooling cycle environment, the abnormal erosion of the tip is inhibited for a long time. The spark plug includes a tip provided on at least one of a center electrode and a ground electrode. The tip includes a body portion, a coating layer, and a high specific resistance layer. The body portion contains mostly Ir, and also contains 2 mass% or more of Rh or Pt, and none of group-A elements or a total content of the group-A elements of 24 mass% or less, the total content of the group-A elements excluding Ru being less than 7 mass%, where the group-A elements are metal elements having a crystal structure different from the crystal structure of Ir, Rh, and Pt at room temperature. The high specific resistance layer is provided on a side peripheral surface of the body portion, has a Ni content greater than the Ni content of the body portion and less than 50 mass%, and has a thickness of 2 µm or greater and 45 µm or less. The coating layer is provided on a side peripheral surface of the high specific resistance layer, contains 50 mass% or more of Ni, and has a thickness of 3 µm or greater and 20 µm or less. The tip has a specific resistance of 20 × 10 -8 ©m or less at room temperature.