Plating Standard
Quality assurance specifications establish performance criteria for electrodeless nickel immersion gold plating applied to printed circuit boards. The ipc-4552b acceptance testing protocol defines minimum gold thickness and maximum allowable nickel corrosion levels for surface finish compliance. Verification prevents solderability failures and black pad defect formation on component land patterns.
Plating thickness ranges are specified to ensure reliable intermetallic formation during automated reflow soldering. Standards governance stops at alternate surface finishes like electroless nickel electroless palladium immersion gold, which are governed by separate IPC specifications.
Deposit Thickness
Thickness measurements utilize X-ray fluorescence spectroscopy calibrated with certified plating standards. Executing ipc-4552b acceptance testing requires taking multiple point readings across dedicated test coupons and component pads. Gold thickness must remain within specified lower and upper control limits to guarantee joint strength while preventing gold embrittlement.
Cross-sectional optical microscopy inspects the nickel layer for localized hyper-corrosion spikes.
Quality Assurance
Solderability testing using wetting balance analysis complements non-destructive physical inspection. Non-compliant lots undergo failure analysis to identify plating bath contamination or chemical imbalances. Printed circuit board buyers require suppliers to provide certified test reports verifying compliance with acceptance criteria.
Lot rejection occurs when nickel corrosion levels exceed allowable rating thresholds established in the standard.
