摘要:
An object of the invention is to provide a higher-durability spark plug provided with a center electrode and a side electrode to form a spark discharge gap between the center electrode and the side electrode, at least one of the center electrode and the side electrode including a precious metal member facing the spark discharge gap, in which a sweating phenomenon of the precious metal member can be suppressed while spark abrasion, oxidation abrasion and abnormal abrasion of the precious metal member can be suppressed. In the invention, the spark plug (100) comprises a center electrode (3), and a side electrode (4) located on one side of the center electrode (3) so that a spark discharge gap (G) is formed between the center electrode (3) and the side electrode (4). The center electrode (3) and the side electrode (4) include first and second precious metal tips (33) and (43) respectively. The first and second precious metal tips (33) and (43) face the spark discharge gap (G) so that the spark discharge gap (G) is formed. The precious metal tips (33) and so on contain Ir as a main component, 0.3 mass % to 43 mass % of Rh, 5.2 mass % to 41 mass % of Ru, and 0.4 mass % to 19 mass % of Ni.
摘要:
In a wire drawing process for forming a wire rod containing iridium as a main component and which further contains nickel and at least one of platinum, rhodium and ruthenium, and having a cross-sectional area of not smaller than 0.05 mm2 and not larger than 1.2 mm2. The worked material is continuously heated red hot and/or white hot in a heating region 103 extending up to 60 mm from the work inserting surface 101a of a die 101 in a direction opposite that in which the work 102 moves, the work being heated to a temperature of 1000 to 1150° C. at a temperature measuring position 105 which is removed from the work inserting surface 101a by 20 mm. Furthermore, the temperature in the region 106 extending from the temperature measuring position 105 to the work inserting surface 101a is set to not lower than 1000° C., and the wire drawing rate is set to 300 to 1600 mm/min.
摘要:
An object of the invention is to provide a spark plug having a discharge portion made of a precious metal tip, in which peeling of the precious metal tip from a surface of the discharge portion can be suppressed while spark abrasion, oxidation abrasion and abnormal abrasion of the discharge portion can be suppressed.
摘要:
In a wire drawing process for forming a wire rod containing iridium as a main component and which further contains nickel and at least one of platinum, rhodium and ruthenium, and having a cross-sectional area of not smaller than 0.05 mm2 and not larger than 1.2 mm2. The worked material is continuously heated red hot and/or white hot in a heating region 103 extending up to 60 mm from the work inserting surface 101a of a die 101 in a direction opposite that in which the work 102 moves, the work being heated to a temperature of 1000 to 1150° C. at a temperature measuring position 105 which is removed from the work inserting surface 101a by 20 mm. Furthermore, the temperature in the region 106 extending from the temperature measuring position 105 to the work inserting surface 101a is set to not lower than 1000° C., and the wire drawing rate is set to 300 to 1600 mm/min.
摘要:
An object of the invention is to provide a spark plug having a discharge portion made of a precious metal tip, in which peeling of the precious metal tip from a surface of the discharge portion can be suppressed while spark abrasion, oxidation abrasion and abnormal abrasion of the discharge portion can be suppressed. The invention comprises a center electrode (3), and a ground electrode (4) disposed so that its side surface is opposite to a leading end portion of the center electrode (3), characterized in that: a center electrode-side precious metal tip (31′) or a ground electrode-side precious metal tip (32′) is welded to at least one of the center electrode (3) and the ground electrode (4) to thereby form a center electrode-side discharge portion (31) having a center electrode-side discharge-surface (31t) or a ground electrode-side discharge portion (32) having a ground electrode-side discharge surface (32t) in a position opposite to a spark discharge gap g; and the center electrode-side precious metal tip (31′) or the ground electrode-side precious metal tip (32′) contains Ir as a main component, Rh, and Ni and further contains at least one of Pt and Pd.
摘要:
A spark plug including: a cylindrical metal shell; a cylindrical insulator fixed to the metal shell; a center electrode having its leading end protruding from a leading end of the insulator and its trailing end fixed to the insulator; and a ground electrode having one end fixed to the metal shell and forming a discharge gap between the ground electrode and the center electrode. The ground electrode includes a precious metal alloy portion containing: 50 weight % or more of a first component of one of Rh and Pt; less than 50 weight % of a second component of the other of Rh and Pt; and optionally a third component containing at least one of: Ni in an amount of less than 7 weight %; and Zr in an amount of less than 2 weight % the content of the third component being less than that of the second component.
摘要:
An object of the invention is to provide a higher-durability spark plug provided with a center electrode and a side electrode. At least one of the center electrode and the side electrode includes a precious metal member facing a spark discharge gap between the electrodes. A sweating phenomenon of the precious metal member can be suppressed while spark abrasion, oxidation abrasion and abnormal abrasion of the precious metal member are suppressed. The precious metal member contains Ir as a main component, and smaller amounts of Rh, Ru, and Ni.
摘要:
A spark plug including: a cylindrical metal shell; a cylindrical insulator fixed to the metal shell; a center electrode having its leading end protruding from a leading end of the insulator and its trailing end fixed to the insulator, and a ground electrode having one end fixed to the metal shell and forming a discharge gap between the ground electrode and the center electrode. The ground electrode includes a precious metal alloy portion containing: 50 weight % or more of a first component of one of Rh and Pt; less than 50 weight % of a second component of the other of Rh and Pt; and optionally a third component containing at least one of: Ni in an amount of less than 7 weight %; and Zr in an amount of less than 2 weight % the content of the third component being less than that of the second component.
摘要:
A noble-metal chip (30, 90) joined to at least either a center electrode or a ground electrode, the center and ground electrodes forming a spark discharge gap, and having a circumferential edge of its facing end surface (31, 91) removed so as to form an edge-removed portion (32, 92). The edge-removal length is 0.01 mm or more and a ratio of the edge-removal length to a radius of the noble-metal chip is less than 0.3. The noble-metal chip is made of iridium or an alloy that contains iridium man amount of 70% by weight or more, and crystal grains constituting the noble-metal chip (30, 90) extends in the axial direction. Also disclosed is a method for manufacturing the spark plug.
摘要:
A noble-metal chip 30, 90 joined to at least either a center electrode or a ground electrode, the center and ground electrodes forming a spark discharge gap, and having a circumferential edge of its facing end surface 31, 91 removed so as to form an edge-removed portion 32, 92. The edge-removal length is 0.01 mm or more and a ratio of the edge-removal length to a radius of the noble-metal chip is less than 0.3. The noble-metal chip is made of iridium or an alloy that contains iridium in an amount of 70% by weight or more, and crystal grains constituting the noble-metal chip 30, 90 extends in the axial direction. Also disclosed is a method for manufacturing the spark plug.