I am experiencing major discrepancies between Nickel/Immersion gold 
     chemistries, on contacting a number of suppliers I have three 
     different recommendations for the Phosphorous content in Nickel as 
     follows:-
     
                      Supplier 1        - 8-10%
                      Supplier 2        - 10-12%
                      Supplier 3        - 12-14%
     
        I am under the impression that as the Phosphorous content increases 
     solderability improves but ductility decreases, does anybody out there 
     have any specific experience of problems caused by too much/too little 
     Phosphorous content in Nickel or is the range of 8-14% an acceptable 
     tolerance band to quote.
     
        Gary Willard  (Motorola UK)