Gordon,

have you notice the grainy aspect you talk about with the lead free solder
pastes ?  

-----Message d'origine-----
De: Davy, Gordon [mailto:[log in to unmask]]
Date: mardi 1 août 2000 18:10
À: [log in to unmask]
Objet: [LF] Solder appearance


A question has been raised about the appearance of solder alloys other than
eutectic SnPb and whether non-shiny is acceptable. The terms "dull" and
"grainy" were used. Allow me to quote from J-STD-001 (para. 9.2.4).

        There are solder alloy compositions, component lead and terminal
finishes, or printed board platings and special solder processes (e.g., slow
cooling with large mass PWBs) that may produce dull, matte, gray, or grainy
appearing solders that are normal for the material or process involved.
These solder joints are acceptable.

The surface of a solder connection has three visual attributes: luster,
texture, and contour. The first two have to do with composition and cooling
rate; the third with wetting. Except for those compositions that are at risk
of lifting (as discussed recently in this forum), wetting is the primary
reliability concern.

Gordon Davy
Northrop Grumman ESSS
Baltimore, MD
[log in to unmask]
410-993-7399

################################################################
Leadfree E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask]
with following text in the body:
To subscribe:   SUBSCRIBE Leadfree <your full name>
To unsubscribe:   SIGNOFF Leadfree
###############################################################
Please visit IPC's Center for Lead-Free Electronics Assembly
(http://www.leadfree.org ) for additional information.
For technical support contact Keach Sasamori [log in to unmask] or 847-790-5315.
################################################################

################################################################
Leadfree E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask]
with following text in the body:
To subscribe:   SUBSCRIBE Leadfree <your full name>
To unsubscribe:   SIGNOFF Leadfree
###############################################################
Please visit IPC's Center for Lead-Free Electronics Assembly
(http://www.leadfree.org ) for additional information.
For technical support contact Keach Sasamori [log in to unmask] or 847-790-5315.
################################################################