It was no secret that Iridium was 6 x harder, 8 x stronger and could take temperatures of 650° C hotter than platinum (i.e. exceeding 2454° C). Unfortunately, the incredible properties that make it the perfect metal for building spark plugs also made it impossible to work with until now.
There wasn’t a welding tool hot enough to melt an iridium electrode tip to a nickel base. That is until DENSO pioneered their patented Laser Welding Process that provides a 360° seal so reliable the electrode resists wear even in the worst conditions.
By harnessing the power of iridium, DENSO were suddenly able to shrink the surface area of the centre electrode tip. Less metal on the tip allows the spark to expand in a greater area, maximising firing performance and minimising voltage requirements.
| Iridium (Ir) | Platinum (Pt) | Nickel (Ni) | Gold (Au) | Silver (Ag) |
|
| Melting Point | 2454 | 1769 | 1453 | 1063 | 960 |
| Strength | 112 | 14 | 68 | 13 | 13 |
| Electrical resistance | 5.3 | 10.6 | 6.8 | 2.3 | 1.6 |
| Hardness | 240 | 40 | 160 | 25 | 26 |
Iridium is approx. 680° C higher than platinum.
Iridium has high material strength compared to other materials and provides stable performance under heavier driving conditions.
Iridium is harder than other materials.
Because Iridium’s is lower than platinum and the base material of electrodes, nickel, it is suitable for use in spark plug electrodes.
To improve firing performance, the contact area between the electrode and the flame nucleus needs to be reduced in size. This is why the electrode was made as fine as possible to a diameter of 0.4mm. Compared to normal Spark Plugs, with a spark gap of 0.8mm, the ignitability limits are better by 2.5.
The required voltage in the Iridium Power plugs is between 3 & 5 kv less than normal plugs. This is due to the ultra-fine 0.4mm diameter ground electrode and U-groove design. Because required voltage is kept low, Iridium Power can be used in high performance engines and for high response driving.
When an engine is idling, firing can become particularly bad. Because Iridium Power plugs have a low required voltage and high ignitability, sparking continues to work properly during idling. Whereas normal plugs have highly variable revolution counts, Iridium Power plugs maintain very smooth idling. Also, because combustion is good, the explosive energy raises the revolution count.
Iridium Power spark plugs enhance the performance of an engine. Acceleration is improved when compared against normal spark plugs.
When Iridium Power spark plugs are used, accidental fire and misfiring rarely occurs under various driving conditions. Therefore, combustion is extremely good. In turn, a healthy engine can be maintained and fuel consumption improved.