Chemistry: electrical and wave energy – Apparatus – Electrolytic
Patent
1993-07-20
1995-03-28
Tung, T.
Chemistry: electrical and wave energy
Apparatus
Electrolytic
2041531, 204400, 204412, 228101, 228103, 228104, G01N 2726
Patent
active
054013801
ABSTRACT:
Apparatus for assessing solderability of electronic component leads and printed wiring boards by sequential electrochemical reduction. The apparatus detects and quantifies the oxides present on copper, solder, andintermetallics that are detrimental to solderability. A solderable portion of the component to be tested is immersed in an electrolyte to form an electrode. An inert counter electrode and a reference electrode are also placed in the electrolyte. A current is passed from the inert counter electrode to the tested component, and the potential between the component and the reference electrode is recorded as a function of time. In a plot of the electrode potential versus the total charge passed, a series of inflection points identify and quantify particular metallic oxides present on the solder. The plot is compared with previous analyses of aged specimens having known oxide compositions that correlate with degradation of solderability. The apparatus is useful for testing off-the-shelf components and for control of circuit board manufacturing and assembly processes.
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Anderson Dennis P.
Tench D. Morgan
McFarren John C.
Rockwell International Corporation
Tung T.
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