I use a $250,000 instrument at my disposal in the lab.

I don't think Cu-Be alloys are designed for electrical contacts.

I think I spoke too soon about tin being a preferred coating material for contacts. Tin is more for leads that get soldered. But it doesn't corrode as quickly as zinc, therefore it is useful as a coating on these fuses. After all, why would the manufacturer go to the trouble of putting tin on zinc?

Benzwood, it's interesting you should mention 24KT gold. I know for a fact that Ford gold plates the contacts at the electrical bulkhead at the firewall (I was contracted to study a problem related to these contacts). And I wouldn't be surprised if it is used for contacts in the air bag system. Gold is the ultimate material you can use for contacts.

I revived this thead because I was under the mistaken impression - perhaps from the sales pitch from the replacement (Cu) fuse manufacturers - that MB fuses are aluminum. I looked at my fuses and saw a dull gray color, so I assumed the sales pitch was correct and my fuses are corroded. I was quite surprised to see that not only are the fuses NOT aluminum, but tin-coated as well, with little corrosion. This explains the dull gray color. But the dissimilar metals in the fuse box can lead to corrosion. Copper or brass fuses would be better in this regard.

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95 E320 Cabriolet, 159K