I'd speculate that the properties of a well formed solder connection processed in air and N2 are indistinguishable. Then again, the pitch is that N2 gives a wider process window, especially for NC flux-types.
In the SMTnet Library look for: �Optimizing the Wave Soldering Process with Hot Nitrogen Knives" Chrys Shea, Siemens, & Gary Shipe, Air Products In the SMTA Knowledgebase look for: �Inerting The Wave Soldering Process With Membrane-Generated Nitrogen�, Chrys Shea, - , 09/12/1999
While directed at reflow, other inerting papers in the SMTA Knowledgebase that may be of interest are: * �Solderability Of Lead Free Metallizations On Board- And Component-Level Under Different Atmospheres, Especially Nitrogen�, Jens Tauchmann, Messer Griesheim. 11/01/2000 * �Solderability Of Different Board Finishes Under Nitrogen Atmospheres With Different ROLs�, Jens Tauchmann, Messer Griesheim, 09/12/1999 * �Solderability Of Printed Wiring Boards With Organic Solder Preservation Under Nitrogen Atmosphere�, Torsten Zachert, Messer Griesheim GmbH, 08/23/1998 * �Reducing Solder Defects Under Nitrogen With Varying Oxygen Concentrations�, H. Hsiao, BOCLH, 04/28/1997
Taking a different angle, contact nitrogen suppliers [eg, Praxair, Air Liquide, BOC, Air Products, etc] for information. A few years [~5-6 erzit 10? My time passes.] ago when nitrogened wave solder machines were the rage, those folk were running around like headless chickens trying to get every wave on the planet converted to N2.
Finally, talk to Brian or Rolland at SMTnet to see if they have a contact for Chrys Shea. Chrys is an x-SMTnetter that is very sharp on wave soldering issues. She might be able to give you the information you seek.
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