1. The use of fluoride-containing additives in the chromium plating solution significantly shortens the service life of the platinized titanium anodes.

Phenomenon Description: The chromium plating tank utilizes a fluoride-containing chromium mist suppressant. Decomposition products from the suppressant adhere to the platinized titanium anodes and corrode the titanium substrate, resulting in a service life of only 16 months for the anode.

Root Cause: The use of fluoride-containing chromium mist suppressants or fluoride-based additives in the chromium plating tank introduces fluoride ions, which corrode the titanium substrate of the platinized titanium anodes. This leads to detachment of the platinum layer and significantly shortens the anode's service life.

Corrective Measures:

a. Completely replace the chromium plating solution and strictly prohibit the use of any additives containing fluoride ions.

b. If fluoride-containing additives must be used, replace the anode in the chromium plating tank with a lead-alloy anode, and reserve the platinized titanium anodes for use in chromium plating tanks free of fluoride additives.

2. Excessively close distance between the cathode and anode causes localized excessive current density on the anode, leading to its damage.

Phenomenon Description: The platinized titanium anodes sections located closer to the work piece are damaged, with the platinum layer completely depleted, while the sections farther from the work piece remain intact with the platinum layer still in good condition.

Root Cause: Uneven distance between the cathode and anode during plating results in higher current density on the anode sections closer to the work piece. This accelerates localized aging of the platinum anode.

Corrective Measures: Regularly reposition the anodes in the plating tank. For example, move the frequently used central anode sections to the less utilized sides, or invert the anodes vertically. This helps ensure more uniform current density distribution across the anodes and prevents localized damage caused by excessively high current density.

3. An inappropriate cathode-to-anode area ratio leads to excessive current density on the anode, thereby shortening its service life.

Phenomenon Description: The platinum layer detaches uniformly across the entire anode, with localized arcing damage observed in some areas.

Root Cause: The initial design of the chromium plating equipment failed to appropriately size the platinized titanium anodes area. During actual production, the cathode-to-anode area ratio falls below 1:1.5, causing the anode to operate at an excessively high overall current density. This leads to premature failure or damage of the platinized titanium anodes.

Corrective Measures:

Determine the maximum allowable current for the plating tank based on the total anode area. As a general principle, the anode current density should not exceed 40 A/dm².

When plating large components where the calculated current would exceed this maximum, reduce the current density and extend the plating time accordingly to achieve the required chromium thickness.

Sustained operation at high current densities accelerates the aging process of platinized titanium anodes and significantly shortens their service life.