> I just say: wow! Real Sci-Fi!//Ingemar//EMW !!?? "Real Sci-Fi" Please explain your comment. Bev Christian Nortel > -----Original Message----- > From: [log in to unmask] > [SMTP:[log in to unmask]] > Sent: Friday, November 27, 1998 2:20 AM > To: [log in to unmask] > Subject: Re: [TN] Tin Oxide > > I just say: wow! Real Sci-Fi!//Ingemar//EMW > > > > > > Kathy, Earl, > > SEM/EDX will not tell you whether you have tin(II) or tin(IV) oxide. > In > > fact, unless you have a very $ expensive EDX it won't tell you if > there is > > any oxygen there at all! Most EDX don't go any lower than sodium in > the > > periodic table. To determine the type of tin oxide present you have > several > > options, all of them but one not easy: > > 1) top-of the-line geology grade mass spec with quantitative > capability > > 2) Auger (will detect oxygen and I presume from the amount you might > be able > > to infer type of oxide?) > > 3) ESCA (determines oxidation state of all elements) > > 4) Mossbauer Spectroscopy (determines oxidation state of tin and some > other > > elements) > > 5) Raman Spectroscopy (like infra-red spectroscopy, measures molecular > > vibrations. There are definite differences between stretching > vibrations of > > tin(II) and tin(IV). May not give good spectra if a lot of organic > crude > > around that will cause the sample to fluoresce.) > > 6) And then there are really fancy things like EELS and PAS, which I > know > > very less about! :) > > and finally > > 7) If there is an accessible, flat surface with this stuff on it you > and > > just use SERA (Sequential Electrochemical Reduction Analysis), a form > of > > chronopotentiometry, which will tell you which oxide and how thick. > > > > regards, > > Bev Christian > > Nortel > > > > > > > -----Original Message----- > > > From: [log in to unmask] [SMTP:[log in to unmask]] > > > Sent: Thursday, November 26, 1998 5:56 AM > > > To: [log in to unmask] > > > Subject: [TN] Tin Oxide > > > > > > Kathy, > > > > > > The answer is not to eliminate tin oxide. It is to prevent it. Once > the > > > oxide is formed, in > > > excessive amounts, it is difficult if not impossible to perform > soldering > > > operations, of any type, > > > to effect acceptable solder joints. When the oxide is present, no > type > > > atmosphere removes it. Your > > > flux didn't. Nitrogen won't as it only prevents. > > > > > > Your oxide analysis should include SEM/EDX. Objectively, this will > show > > > type and amount present. > > > When excessive, cause is found and eliminated to prevent further > > > occurrences. > > > > > > To prevent it is not always easy either. This especially is true > when the > > > tin coating process is not > > > effectively managed (sometimes difficult) or post coating handling > and > > > storage requirements are not > > > met (less difficult). Most tin coatings oxidize readily and rapidly. > A > > > newer type (white) is said > > > not to do so, though I've not had the opportunity to see evidence. > > > > > > Enjoy, > > > > > > Earl Moon > > > > > > ################################################################ > > > 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 > ################################################################ ################################################################ 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 ################################################################