71
What type of material is used to produce the
electrode employed for ?
A precious metal similar to platinum, iridium,
a member of the platinum group with the atomic number 77,
is extremely strong and has an unusually high melting point.
2454
1769
1453
1063
960
112
14
68
13
13
240
40
160
25
26
5.3
10.6
6.8
2.3
1.6
Iridium is harder than other materials
and has great material strength.
Hardness
Because the electrical resistance is lower than
platinum and the base material of electrodes, nickel,
iridium is suitable for use in spark plug electrodes.
Electrical
resistance
Iridium has high material strength compared
to other materials and provides stable
performance under heavier driving conditions.
Strength
The melting point of iridium is approximately 680
℃
higher than
that of platinum and is difficult to melt even in the high
temperatures produced by electrical discharges and combustion.
Melting
point
Melting points of various metals
500
1000
1500
2000
2500
Iridium
Platinum
Nickel
Gold
Silver
Element
Melting point
(
℃
)
Melting point
(
℃
)
Strength
(kgf/mm
2
)
Hardness
(HV, 20
℃
)
Iridium
(Ir)
Platinum
(Pt)
Nickel
(Ni)
Gold
(Au)
Silver
(Ag)
Electrical
resistance
(
µΩ
cm)