Today@Dal

From the December 27 Globe and Mail:

A friend and I tried to put winter tires on my car today, but we couldn’t get the all-season tires off. First I tried kicking them, hitting them with a hammer, and then a big sledge hammer. I then loosened the nuts and drove up onto the curb, and swerved back and forth, but nothing worked, they’re rusted on tight.

The culprit is corrosion – an electrochemical reaction between metal and oxygen when metal is exposed to water. The metal gets eaten away as it surrenders electrons to the oxygen. Salt makes it happen faster. Halifax has plenty of water and salt.

“Our moist sea air creates a hot bed for corrosion,” says Dalhousie University engineering professor Stephen Corbin. “If he parked his car in a warm moist area like a garage or spent a lot of time by the seaside, that could speed up corrosion.”

The fusing is confusing, though. It doesn’t happen at all with steel wheels on steel hubs, because they’re both the same material.

And it doesn’t happen with every aluminum alloy wheel.

Some metals corrode more easily than others. When an active metal (a metal that corrodes easily) is touching a less active metal (a metal that doesn’t corrode easily), the two form a galvanic couple, Corbin says.

Read the rest of this article at The Globe and Mail online.