Summary for hard chrome plating defects Discussion
Hard chrome plating HCD area issues are discussed in the context of bath chemistry and catalyst balance. The excerpt notes that readers new to chrome plating should first understand the difference between hard chrome and decorative chrome, and it explains that chrome will not plate properly without a catalyst in the solution at a carefully controlled ratio. The most common catalyst mentioned is sulfate (SO4-2), typically around 1 part per 100 parts of chrome. Popatbhai B. Patel, an electroplating consultant in Roseville, Michigan, warns that if the catalyst ratio is too high, problems can occur, though the excerpt cuts off before listing the specific defect. The thread title suggests the issue involves random growths or dots on hard chrome plating in the HCD area, pointing readers toward bath control as the likely area to investigate.
Quickstart:
Readers who are unfamiliar with chrome plating or who don’t understand how “hard chrome” differs from decorative chrome may wish to start with our “Intro to Chrome Plating”.
Regarding the ‘barium carbonate’ mentioned in the thread: chrome will not plate without a ‘catalyst’ present in the solution in a carefully controlled ratio, neither too high nor too low. The most common catalyst is sulfate (SO4 -2) at a ratio of about 1 part per 100 parts of chrome. If the ratio is too high, the addition of barium chromate will reduce it.
Chrome plating will “burn” ⇦ huh? if the “current density” ⇦ huh? is too high; parts being plated will usually have different current density at different spots on the part; there will be some HCD (high current density) areas.
Q. I have issues with hard chrome plating:
We have plated shock absorber cylinders
1. surface area 3955 cm2
2. at 1700 A, 43 a/dm2
3. temperature 55-58 C
4. Metal contamination 2 g/l
5. solution within control range
We have plated at this current for this part for 3 years.
However, this Rather growths white dot suddenly found on high current area (top & bottom). After we transfer solution out for bath maintenance and chemist adjust sulfate ratio with Barium carbonate. (just FYI, after analyzed the ratio still in range).
What is the cause of the defect? Has anybody ever found this defect?
Many people think of high current, but the rectifier was just calibrated and we’ve used this intensity and fixed it for 3 years.
Sarun Triwittayayont
– Bangkok, Thailand
June 29, 2025
A. Sarun,
I saw the part’ picture looks like chrome burn at HCD area
check the chrome ratio, should be 1:100
check chrome concentration and temperature
maybe current is too high
try to put bleeder both sides of the rack
Popatbhai B. Patel
electroplating consultant – Roseville, Michigan
September 1, 2025