公开(公告)号：US20180048126A1

公开(公告)日：2018-02-15

申请号：US15669536

申请日：2017-08-04

申请人： NGK Spark Plug Co., LTD.

发明人： Yutaka YOKOYAMA ,  Kuniharu TANAKA ,  Nobuyoshi ARAKI ,  Hirokazu KURONO ,  Toshimasa SAJI ,  Yusuke NOMURA ,  Jumpei ISASA

IPC分类号： H01T13/38 ,  C04B35/10 ,  H01B3/12

CPC分类号： H01T13/38 ,  C04B35/10 ,  C04B35/111 ,  C04B35/62655 ,  C04B35/63416 ,  C04B2235/3206 ,  C04B2235/3208 ,  C04B2235/3213 ,  C04B2235/3215 ,  C04B2235/3217 ,  C04B2235/3222 ,  C04B2235/3418 ,  C04B2235/3481 ,  C04B2235/5436 ,  C04B2235/5445 ,  C04B2235/6565 ,  C04B2235/6567 ,  C04B2235/85 ,  H01B3/12

摘要： An alumina-based sintered body includes 92 mass % to 96 mass % of Al in terms of an oxide, and at least three elements selected from Group II elements, one of the at least three elements being 1.90 mass % or more of Ba in terms of an oxide. The alumina-based sintered body includes the following phases in a grain boundary phase present between alumina crystal grains: a first crystal phase containing Si and at least one of the Group II elements, and a second crystal phase containing Al and at least one of the Group II elements. In X-ray diffraction of the alumina-based sintered body, the maximum relative intensity of the first crystal phase and the maximum relative intensity of the second crystal phase are both 2 or above relative to the maximum diffraction intensity of the alumina crystal.

公开(公告)号：US20170093134A1

公开(公告)日：2017-03-30

申请号：US15272807

申请日：2016-09-22

申请人： NGK SPARK PLUG CO., LTD.

发明人： Yutaka YOKOYAMA ,  Kuniharu TANAKA ,  Katsuya TAKAOKA ,  Shun KONDO ,  Nobuyoshi ARAKI ,  Toshiki KON ,  Haruki YOSHIDA ,  Jumpei ISASA ,  Hirokazu KURONO ,  Hironori UEGAKI ,  Toshimasa SAJI ,  Yusuke NOMURA

IPC分类号： H01T13/38

CPC分类号： H01T13/38 ,  H01T13/60

摘要： A spark plug including an insulator containing not less than 92 mass % and not greater than 96 mass % of Al component in terms of oxide, wherein the insulator is formed from an alumina sintered body comprising alumina crystal and a grain boundary phase present between crystal grains of the alumina crystal. Assuming that mass contents of an Si component, an Mg component, a Ba component, and a Ca component in terms of oxide are represented by MSiO2, MMgO, MBaO, and MCaO, respectively, and a sum of MSiO2, MMgO, MBaO, and MCaO is represented by Mt, the grain boundary phase contains these components so as to satisfy conditions (1) to (4) as follows: (1) 0.17≦MSiO2/Mt≦0.47; (2) 0.005≦MMgO/Mt≦0.07; (3) 0.29≦MBaO/Mt≦0.77; (4) 0.03≦MCaO/Mt≦0.19.

公开(公告)号：US20170093133A1

公开(公告)日：2017-03-30

申请号：US15272561

申请日：2016-09-22

申请人： NGK SPARK PLUG CO., LTD.

发明人： Haruki YOSHIDA ,  Jumpei ISASA ,  Toshitaka HONDA ,  Yutaka YOKOYAMA ,  Kuniharu TANAKA ,  Nobuyoshi ARAKI ,  Toshiki KON

IPC分类号： H01T13/38 ,  H01T13/18

CPC分类号： H01T13/38 ,  H01T13/18 ,  H01T13/60 ,  H01T21/02

摘要： A spark plug includes an insulator, a center electrode, a metallic shell, and a ground electrode. The insulator contains not less than 90.0 mass % and not greater than 98.1 mass % of Al2O3 with respect to a total mass of elements, as reduced to oxides, contained in the insulator, and has a porosity not greater than 5%. Assuming that a porosity of the insulator after a heat treatment is B, a difference (B−A) of the porosities before and after the heat treatment is not greater than 3.5%. In the heat treatment, the insulator is placed in a furnace, and a temperature in the furnace is increased from a room temperature to 1400° C. at a temperature increase rate of 7° C./min and is held at 1400° C. for 30 minutes, and thereafter, the temperature is decreased from 1400° C. to 400° C. at a temperature decrease rate of 10° C. or less per 5 minutes and is decreased to the room temperature.

公开(公告)号：US20170093132A1

公开(公告)日：2017-03-30

申请号：US15265152

申请日：2016-09-14

申请人： NGK Spark Plug Co., LTD.

发明人： Jumpei ISASA ,  Haruki YOSHIDA ,  Yutaka YOKOYAMA ,  Kuniharu TANAKA ,  Nobuyoshi ARAKI ,  Toshiki KON

IPC分类号： H01T13/38

CPC分类号： H01T13/38

摘要： A spark plug includes an insulator made of an alumina sintered body containing Al2O3 as a principal component and additional components including; an Si component, a Ba component, an Mg component, a Ca component, an Sr component, and a rare earth element component. When the additional components are expressed as oxides including RSiO2, RBaO, RMgO, RCaO, RSrO, and RRE2O3, contents (mass %) of the sub-component satisfy expressions (1) to (6) as follows: (1) 1.0≦RSiO2≦5.0; (2) 0.5≦RBaO≦5.0; (3) 0≦RMgO≦0.18; (4) 0≦RMgO/RBaO≦0.36; (5) 0.3≦(RMgO+RCaO+RSiO)≦1.8; and (6) 0≦RRE2O3≦0.1.