3 Misconceptions of Zinc Black Trivalent
Zinc black trivalent is widely chosen for its ability to protect parts from corrosion while offering a dark to deep black appearance, which can range depending on the surface condition of the part.
It offers up to 120 hours of salt spray protection and works well in applications where parts need to blend in with other components such as:
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Off-road vehicle components
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Farming equipment
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Undercar automotive parts
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Recessed fixtures
Unlike other zinc chromates, Black Trivalent Chromate is a two-step process consisting of the plating chromate followed by a reactive sealer. The sealer and chromate work in combination to provide a dark coloring with optimal corrosion protection.
Understanding the capabilities and limitations of black trivalent are critical for establishing reasonable expectations for this finish.
Misconception #1
It will produce a uniform / cosmetic finish.
Due to the nature of the sealer, streaks, drip marks and accumulation of plating on part edges may be present.
While Gatto uses its best efforts to minimize cosmetic inconsistencies, secondary processes such as painting, or powder coating should be considered for highly cosmetic applications.
Misconception #2
It will provide similar dimensional change as other zinc finishes.
The organic resin topcoat/sealer required for black trivalent may pool in areas such as edges or around holes which can potentially affect critical dimensions of the part.
Misconception #3
Accumulation on edges is a sign of poor plating.
Build-up on part edges is an accumulation of the sealer, not the plating. These sections can cause the sealer to break or chip-off creating a lighter appearance in certain areas. While we do our best to minimize this occurrence, it is not a condition that can be easily controlled.
NOTE: Chipping or flaking of the sealer will not affect the performance of the plating as both the zinc and chromate are still intact providing corrosion protection to the surface.