Brian,
I agree that SF6 is a horrible material: GWP = 23,900, atmospheric lifetime
of > 3200 years, WAY more than 25 generations! I may have my doubts about
man-made global warming in general, but as a fluorine chemist I sure don't
want to see any more of this stuff made.
There is awful lot of it still around. It can only be effectively destroyed
by bubbling through molten caustic, or introduction to an electric arc or
plasma discharge. It is extremely stable because it is sterically hindered
(Each sulfur atom is more or less completely surrounded by the six fluorine
atoms. I know you know this, Brian, but I am explaining for others.). So if
we can destroy some of it in industrial processes that would be good. Of
course the system needs to have scrubbers on it to capture anything not
destroyed. But since it condenses easily, this is not that hard.
Our power generation companies have literally tonnes of the stuff. Typical
SF6 insulated transformers lose 0.5% per year. A quick look at Google says
that British Columbia Hydro lost 3.26 tonnes of the stuff to the atmosphere
in 1999. Ironically it was introduced to replace PCBs as the fluid in high
voltage transformers.
Bev
RIM
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Brian Ellis
Sent: Friday, May 21, 2010 11:50 PM
To: [log in to unmask]
Subject: Re: [TN] RE : Sapphire wafer etching
I would try to avoid SF6 for environmental reasons. It's the world's
WORST greenhouse gas, tens of thousands of times worse than CO2, with a
"half-life" exceeding 25 human generations, at least. It is listed in
the Kyoto Protocol.
Brian
Tharaka Chandanayaka wrote:
> Hi everyone,
>
> I was wondering that anyone came across any methods that can etch Sapphire
> wafers in low temperatures. If know please let me know. Tech net is a
great
> source of information.
>
> Thank you
> Tharaka Chandanayaka
> [log in to unmask]
>
> ---------------------------------------------------
> Technet Mail List provided as a service by IPC using LISTSERV 15.0
> To unsubscribe, send a message to [log in to unmask] with following text in
> the BODY (NOT the subject field): SIGNOFF Technet
> To temporarily halt or (re-start) delivery of Technet send e-mail to
[log in to unmask]: SET Technet NOMAIL or (MAIL)
> To receive ONE mailing per day of all the posts: send e-mail to
[log in to unmask]: SET Technet Digest
> Search the archives of previous posts at: http://listserv.ipc.org/archives
> Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16
for additional information, or contact Keach Sasamori at [log in to unmask] or
847-615-7100 ext.2815
> -----------------------------------------------------
>
______________________________________________________________________
This email has been scanned by the MessageLabs Email Security System.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to
[log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to
[log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16
for additional information, or contact Keach Sasamori at [log in to unmask] or
847-615-7100 ext.2815
-----------------------------------------------------
______________________________________________________________________
This email has been scanned by the MessageLabs Email Security System.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------
|
