Yeah, but is there a permanent way of knowing? Maybe open a new train of
thought. Please don't rail at me as I hope to be a tender sleeper
tonight, when I switch off, and I hold no truck at being disturbed,
despite all the points raised.
Brian
Inge wrote:
> Yes, you probably can. By means of a microscopic sample, it ought to be
> possible to see in a SEM. When the steel wheels pass, nanosized friction
> weldings are created. When the last wheel pass, these tiny weldings are
> broken. The way the fractures look will tell in what direction the wheel
> moved. But it's a bit of expensive way. A timetable is cheaper.
>
> Inge
>
>
> ----- Original Message ----- From: "Douglas Pauls"
> <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Thursday, April 16, 2009 10:20 PM
> Subject: Re: [TN] NTC - [TN] Gold/Tin Intermetallics, why are we afraid?
>
>
>> Well Dave, just remember this bit of wisdom - you can't tell which
>> direction a train was movin' from the tracks.
>>
>> Doug Pauls
>> Rockwell Collins
>>
>>
>>
>> "David D. Hillman" <[log in to unmask]>
>> Sent by: TechNet <[log in to unmask]>
>> 04/16/2009 02:53 PM
>> Please respond to
>> TechNet E-Mail Forum <[log in to unmask]>; Please respond to
>> [log in to unmask]
>>
>>
>> To
>> [log in to unmask]
>> cc
>>
>> Subject
>> Re: [TN] NTC - [TN] Gold/Tin Intermetallics, why are we afraid?
>>
>>
>>
>>
>>
>>
>> Hi Joyce! Authority??????? I am just a lowly engineer trying to find the
>> light at the end of the tunnel without having all the alligators in the
>> swamp get me first. My luck will be that the light at the end of the
>> tunnel is Doug driving a train!
>>
>> Dave
>>
>>
>>
>> Joyce Koo <[log in to unmask]>
>> Sent by: TechNet <[log in to unmask]>
>> 04/16/2009 02:48 PM
>> Please respond to
>> TechNet E-Mail Forum <[log in to unmask]>; Please respond to
>> Joyce Koo <[log in to unmask]>
>>
>>
>> To
>> [log in to unmask]
>> cc
>>
>> Subject
>> Re: [TN] Gold/Tin Intermetallics, why are we afraid?
>>
>>
>>
>>
>>
>>
>> Ha, the authority is spoken!
>>
>> -----Original Message-----
>> From: TechNet [mailto:[log in to unmask]] On Behalf Of David D. Hillman
>> Sent: April 16, 2009 3:32 PM
>> To: [log in to unmask]
>> Subject: Re: [TN] Gold/Tin Intermetallics, why are we afraid?
>>
>> Hi Joyce - my response would "it depends" (and Doug gets another Diet
>> Mt.
>> Dew) as Rockwell Collins utilizes immersion silver pwb surface finishes
>> on
>> many IPC Class 3 type products with no reliability issues.
>>
>> Dave
>>
>>
>>
>> Joyce Koo <[log in to unmask]>
>> Sent by: TechNet <[log in to unmask]>
>> 04/15/2009 04:11 PM
>> Please respond to
>> TechNet E-Mail Forum <[log in to unmask]>; Please respond to
>> Joyce Koo <[log in to unmask]>
>>
>>
>> To
>> [log in to unmask]
>> cc
>>
>> Subject
>> Re: [TN] Gold/Tin Intermetallics, why are we afraid?
>>
>>
>>
>>
>>
>>
>> "ImAG finishes have a 12-month shelf life in a controlled environment
>> (<35[degrees]C/<85[degrees] RH), which can be significantly shortened
>> when exposed to air pollution with high sulfur and chlorine content.
>> Silver embrittlement Embrittlement
>>
>> A general set of phenomena whereby materials suffer a marked decrease in
>> their ability to deform (loss of ductility) or in their ability to
>> absorb energy during fracture (loss of toughness), with little change in
>> other mechanical properties, such ([Ag.sub.3]Sn intermetallics) of
>> solder joints may occur when the finish thickness exceeds IPC-4553
>> recommendations and Pb-free, high silver content solders are used. ImAG
>> is not recommended for high-reliability assemblies that must meet
>> IPC-6010 Class 3 requirements, but is acceptable for Classes 1 and 2."
>>
>> http://www.thefreelibrary.com/Will+discoloration+tarnish+ImAg+reliabilit
>> y%3F+Watch+for+silver...-a0193896272
>>
>> -----Original Message-----
>> From: TechNet [mailto:[log in to unmask]] On Behalf Of Werner Engelmaier /*
>> Sent: Wednesday, April 15, 2009 4:34 PM
>> To: [log in to unmask]
>> Subject: Re: [TN] Gold/Tin Intermetallics, why are we afraid?
>>
>>
>> Hi Vlad,
>> I cannot comment on your specific case, but look at the pics below to
>> see
>> Ag-embrittlement.
>> Sorry 'Netters, IPC strips pics.
>>
>> Werner
>>
>> ---------------------------------------------------
>> 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 transmission (including any attachments) may contain confidential
>> information, privileged material (including material protected by the
>> solicitor-client or other applicable privileges), or constitute
>> non-public
>> information. Any use of this information by anyone other than the
>> intended
>> recipient is prohibited. If you have received this transmission in
>> error,
>> please immediately reply to the sender and delete this information from
>> your system. Use, dissemination, distribution, or reproduction of this
>> transmission by unintended recipients is not authorized and may be
>> unlawful.
>>
>> ---------------------------------------------------
>> 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
>> -----------------------------------------------------
>>
>>
>> ---------------------------------------------------
>> 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 transmission (including any attachments) may contain confidential
>> information, privileged material (including material protected by the
>> solicitor-client or other applicable privileges), or constitute
>> non-public
>>
>> information. Any use of this information by anyone other than the
>> intended
>>
>> recipient is prohibited. If you have received this transmission in error,
>> please immediately reply to the sender and delete this information from
>> your system. Use, dissemination, distribution, or reproduction of this
>> transmission by unintended recipients is not authorized and may be
>> unlawful.
>>
>> ---------------------------------------------------
>> 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
>> -----------------------------------------------------
>>
>>
>> ---------------------------------------------------
>> 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
>> -----------------------------------------------------
>>
>>
>> ---------------------------------------------------
>> 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
>> -----------------------------------------------------
>
> ---------------------------------------------------
> 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
> -----------------------------------------------------
>
---------------------------------------------------
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
-----------------------------------------------------
|
