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Gold diffusion rates

 

Could anyone furnish me with gold / copper diffusion rates at elevated temperatures (to approximately 250C) with and without a nickel barrier? I am working with a customer who has experienced electrical contact failures in a high power RF relay which I attribute to rapid diffusion (thus oxidation causing increased contact resistance causing thermal runaway causing failure) because no barrier is used. He accepts that it is good engineering practice to include a barrier and intends to incorporate one but he'd like some quantification of the improvement to be expected.

My own background in this area is pathetic and my literature and WWW searches haven't been fruitful.

Any help would be much appreciated.

Thanks,

George A. Flanagan
- Smithtown, New York

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I believe that the diffusion rate is fast enough that you could plate a thin (a few microns) of gold over copper, and you could almost watch it diffuse into the copper at 250C. For nickel it may take months or years. You may be able to get a relative diffusion rate from a simple test like that.

  
Tom Pullizzi
Falls Township, Pennsylvania