In the modern surface treatment industry, traditional hexavalent chromium processes are rapidly being replaced by trivalent chromium technologies due to strict global environmental regulations such as RoHS and REACH directives. For B2B buyers in Southeast Asia and worldwide, selecting a passivator that meets compliance while maintaining high corrosion resistance is critical. TR-138 Trivalent Chrome Multicolor Passivator, an eco-friendly process free of hexavalent chromium and oxidizers, has become a mainstream choice for the post-treatment of zinc and zinc alloy plating.
The technical advantage of TR-138 lies in its ability to form a dense and chemically stable passivation film on metal surfaces. This process produces coatings with a clear, greenish, rainbow-like appearance.
Material Compatibility: Specifically designed for multicolor passivation of zinc and zinc alloys, offering excellent adhesion.
Antioxidation Principle: By immersion at an operating temperature of 10-40℃, the solution reacts with the metal surface to create a barrier layer that blocks oxygen contact with the substrate.
Parametric Stability: The gravity of TR-138 concentrate is strictly controlled at 1.425± 0.02 g/ml, ensuring consistent film formation.
When evaluating passivator stability, B2B buyers should focus on specific parameters rather than marketing slogans. The performance of TR-138 is verified by several international standards.
Salt Spray Testing: Its anticorrosive properties exceed the requirements of hexavalent multicolor passivation according to DIN 50 021 SS.
Automotive Industry Access: The product complies with American standards GME00252 and GMW-3011, meeting the rigorous oxidation resistance requirements of automotive supply chains.
Wide Operating Window: The pH range of 1.6-2.4 provides the tolerance necessary for stable film quality in large-scale industrial production.
TR-138 resolves technical compliance issues while offering operational advantages to electroplating facilities.
Wastewater Treatment: Utilizing a trivalent system without oxidizers significantly reduces wastewater disposal costs and aligns with modern green factory requirements.
Long Service Life: The bath maintains a long service life even with the feedback of rinse-water.
Aesthetic Versatility: Beyond the basic iridescent color, the layer can be dyed with organic colorings for decorative purposes.
To ensure long-lasting oxidation resistance, operators must strictly monitor process parameters.
pH Correction: Slight white clouds on the layer are often caused by a high pH value; it should be corrected to approximately 1.8 using nitric acid.
Impurity Control: High iron content in the bath can cause a yellowed appearance and poor protection. In such cases, iron can be precipitated by raising the pH to 3.5 using sodium hydrogen carbonate.
Precise Replenishment: For every 1L of bath brought out, it is recommended to add 125ml of TR-138 concentrate to maintain chemical equilibrium.
