Concerned About the Use of Aluminum and Magnesium in the Z06 and Road Salt?

[Rob]

In the past, I've had friends ask me what the effects of road salt and chemicals used in the frostbelt region of the US will have on the aluminum and magnesium components used on the upcoming 2006 Z06. Because I'm not a metallurgist, I wasn't able to give much of a response other than: "I'm sure Corvette Engineers have thought about that and addressed the issue during development and testing."

In the Sept. 2005 issue of Corvette Magazine, someone wrote a letter to the "Ask a Tech Nerd" about this same question and I thought I'd post the question and response here:

....Along with probably most of the other folks pondering the new Corvette, I've been salivating over the Z06. As a practical matter, however, I'm not sure that it would be the best choice for someone who drives in the Mid-Atlantic states, where chemicals are routinely applied to the roads in the winter.

In Central Virginia, where I live, chemicals are usually only applied selectively on certain bridges, overpasses, and critical intersections--it ain't Buffalo. They do tend to stay around on the roads in dust form for a few days after the snow is gone, though.

I doubt I would have my new Corvette out in the snow for anything less than a life-or-death emergency, but I'd like to know how concerned buyers should be about these kinds of chemicals contacting the Z06's aluminum and magnesium components.

I'm well aware that aluminum has been used in more mundane forms of transportation for years, but is magnesium of greater concern? I plan to keep the car for a very long time.

While aluminum obviously doesn't rust, it does corrode; just look at an old uncoated aluminum wheel or a blown out used water pump. Thus, the Z06's aluminum chassis actually gets corrosion-resistant treatments and coatings in much the same way that the standard C6's steel frame is protected. (Some of the people who worked on the program wanted to leave the chassis unpainted to emphasize the car's high-tech construction--well, and because it looked boss, too--but safety and durability were deemed more important than glamour.)

Similarly, while magnesium doesn't rust like a ferrous metal it has several other issues, not least of which being its tendency to corrode in the presence of water and certain chemicals, especially chlorides. To improve the material's stability, the magnesum used in the Z06 (and most other products), is combined in an alloy with aluminum, zinc, manganese, and other metals before forming, then given additional surface treatments for added protection.

The bottom line is that whether a vehicle's chassis and suspension components are made out of aluminum, magnesium, or steel, the materials all have to meet pretty much the same corrosion-resistance standards to be commercially viable nowadays. Take good care of your new Z06 and it will probably outlive you by decades. Use it three times a week as a boat-launching vehicle, and it won't be around for your first parking spot in the old-folks home.

 

[DkBG]

Thats interesting reading . I haven't noticed much corrosion on the C4 suspension parts . And what little I did see was just on the surface and didn't appear to be a problem . Most cars nowadays have a lot of Aluminum underneath for weight savings and gas milage . Engine cradles , tranny cases and such . My limited experience with magnesium , mostly with off road motorcycles , have shown it to be just as durable . Cliff

 

[Mac]

My limited experience with magnesium , mostly with off road motorcycles , have shown it to be just as durable . Cliff

Back in 2001, I was the lead investigator of a small aircraft crash. With the assistance of divers, we recovered many parts of the aircraft but the brief immersion in the ocean turned the magnesium intakes into white powder. Hopefully, the alloy of metals and anti-corrosion treatments on the Z06 parts will prevent this.

-Mac