hi,
i am certainly no guru, but it seems to me that your chassis was zinc plated
and chromate conversion coated with a CLEAR chromate conversion coating for
cosmetic purposes. unfortunately, clear chromate conversion coating doesn't
resist corrosive things like finger prints. i personally think that NATURAL
chromate conversion coatings (yellow) are the only way to go.
phil crepeau
-----Original Message-----
From: Kathy Stillings [mailto:[log in to unmask]]
Sent: Friday, May 21, 1999 9:13 AM
To: [log in to unmask]
Subject: [TN] HELP - NEED INFO ON PLATING ISSUE
Hi Everyone,
Was wondering of I could get some input from any Guru on plating issues.
Need info ASAP!!!!!!!!!!!!!!!!!!!! Here's the problem: have a zinc plated
chassis with a base of stainless steel and the handle is brass plated with
nickel. We have finger prints that can't be removed and a wash-like
streaking across the surface of the material. This stuff "oxidizes" just
sitting in a room and transportation overseas only accelerates the process.
Desiccant agents don't even work.
Testing found iron oxidation randomly spaced along some finger print
patterns. Unsuccessful attempts were made to lift the deposits using tape.
Samples were then cut for testing evaluation. SEM/EDS analysis showed
trace elements of zinc, low levels of chrome, oxygen, aluminum, calcuim
chloride, phosphorus, carbon, chlorine, iron, potassium, silicon, and
sulfur. Higher levels of "corrosive" chlorine were found in fingerprint
areas with small definitive locations of very high calcium. Initiation of
the corrosion has been determined to be at the plating.
Is it possible the plating vendor is using a washing agent after plating
that contains the corrosives mentioned above and over time these elements
are leaching out and corroding the plating? Can someone shed some light in
this issue? We've been using the plating for 6 years and this is a new
occurrence.
################################################################
TechNet 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 TechNet <your full name>
To unsubscribe: SIGNOFF TechNet
################################################################
Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section
for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or
847-509-9700 ext.312
################################################################
################################################################
TechNet 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 TechNet <your full name>
To unsubscribe: SIGNOFF TechNet
################################################################
Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312
################################################################
################################################################
TechNet 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 TechNet <your full name>
To unsubscribe: SIGNOFF TechNet
################################################################
Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312
################################################################
|
