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 Post subject: Is the temperature for Be diffusion higher than for Ti
PostPosted: Tue Sep 11, 2012 3:33 am 
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Well I guess I asked in my title :) If anyone could just give me a quick answer to save me even more hours online I would appreciate it!

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 Post subject: Re: Is the temperature for Be diffusion higher than for Ti
PostPosted: Tue Sep 11, 2012 11:15 am 
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Titanium ions are bigger than Beryllium ions. You do the math...

There is a difference between the two diffusion treatments btw in terms of diffusion rates within economically viable circumstances. Keeping time and temperature equal, what would be the outcome regarding depth of penetration?


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 Post subject: Re: Is the temperature for Be diffusion higher than for Ti
PostPosted: Tue Sep 11, 2012 11:22 am 
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The temperature can be offset by pressure, no?


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 Post subject: Re: Is the temperature for Be diffusion higher than for Ti
PostPosted: Tue Sep 11, 2012 11:29 am 
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even if the treatment is performed in "controlled atmosphere" i don't think that actually means pressures higher than 1 bar....... :wink:

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albé

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 Post subject: Re: Is the temperature for Be diffusion higher than for Ti
PostPosted: Tue Sep 11, 2012 12:25 pm 
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If I remember Dr. Emmett correctly, temperature and pressure are the same but time increases or penetration depth decreases with Ti compared to Be.

If I got that wrong, it's my lousy memory, not Dr. Emmett's excellent talk.

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 Post subject: Re: Is the temperature for Be diffusion higher than for Ti
PostPosted: Tue Sep 11, 2012 12:44 pm 
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Quote:
The temperature can be offset by pressure, no?


if you would increase pressure you would increase the melting temperature of corundum thus lowering the diffusion rate at the same temp-time level... You'd (theoretically) wanna lower the pressure in order to increase diffusion rates. Given the fact that we can only go one bar lower from where we are pressure is out of the equation somewhat... It's all about temp, time, ion size and structure of the stuff we want to pump those ions into as far as I'm aware...


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 Post subject: Re: Is the temperature for Be diffusion higher than for Ti
PostPosted: Wed Sep 26, 2012 11:56 pm 
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Lisa Elser wrote:
If I remember Dr. Emmett correctly, temperature and pressure are the same but time increases or penetration depth decreases with Ti compared to Be.

If I got that wrong, it's my lousy memory, not Dr. Emmett's excellent talk.


You can read John's article based on his lecture here:

http://www.ruby-sapphire.com/pdf/Emmett-2011-Beryllium-and-Beefsteak.pdf

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