Common faults and correction methods for plastic electroplating-decorative chromium plating
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Insufficient brightness
a) Low temperature or high current density
b) Low sulfate content
c) High trivalent chromium
d) High iron impurity content
correction method
a) Raise the temperature and check whether the current is within the process range
b) Analytical supplement
c) Electrolysis with large anode and small cathode
d) Electrolysis with ion exchange or membrane
Poor coverage
a) High temperature and low current density
b) High sulfuric acid content,
c) Insufficient trivalent chromium
d) High impurities in zinc, copper and iron
correction method
a) Reduce and check whether the current is within the process range
b) After analysis, BaCO3 was used to remove part of the sulfate;
c) Electrolysis with large cathode and small anode
d) Ion exchange or membrane electrolysis treatment
local chromium-free layer
a) The holes are not blocked
b) Improper installation and hanging, resulting in air pockets or poor conduction
c) The parts are complex in shape and no auxiliary anode is used
d) Mutual shielding of parts
e) Oil stains on the surface of the plated parts
f) The hanging device is not insulated
correction method
a) Plug it with plastic pipe
b) Switch to hanging equipment
c) Select appropriate auxiliary anode
d) Less hanging parts
e) Reprocess the plated parts
f) Improve hanger insulation
The chrome plating layer is peeled off together with the nickel plating layer
a) Incomplete pre-plating treatment
b) High internal stress in nickel plating layer
correction method
a) Strengthen plating pretreatment
b) Adjust the nickel plating solution
Black flowers appear during chromium plating on copper-tin alloy coating
a) Low solution temperature
b) Incomplete pretreatment of chromium plating
c) Power on too fast or too slow
e) Excessive tin content in copper-tin alloys
correction method
a) Increase the temperature
b) Strengthen chrome plating pretreatment
c) Improve operations
e) Adjusting copper-tin alloy
hard chromium plating
plating peeling
a) Poor pre-plating treatment
b) Power off during the chrome plating process
c) Short preheating time for parts entering the slot
d) Solution temperature or cathode current density changes too much
e) Excessive sulfuric acid content
correction method
a) Strengthen plating pretreatment
b) When re-plating, perform anodic treatment or cathode small current activation treatment
c) Extend warm-up time
d) Strictly control solution temperature and cathode current density
e) Treatment with barium carbonate
Cast iron cannot be plated with chromium,
Only hydrogen evolution reaction
a) Excessive etching before plating
b) During anodic treatment, graphite is exposed
c) Cathode current density is too low
correction method
a) Re-process and then plating
b) Re-process and then plating
c) Increase cathode current density
The coating is rough and has chrome bumps
a) Excessive cathode current density
b) The distance between cathode and anode is too close
c) Part shape is convex and no protective cathode is used
d) Excessive sulfate
correction method
a) Reduce cathode current density
b) Relax the distance between cathode and anode
c) Use suitable protective cathode
d) Add barium carbonate treatment
Obvious cracks in coating or underlying metal
Steel is stressed during quenching
Tempering parts to relieve stress before plating
