While the use of hexavalent chromates has been a staple of the metal finishing industry for many years, recent years have seen compelling research questioning the safety of using hexavalent chromium-based systems. Great Lakes Metal Finishing is experienced in effectively using both trivalent chromate, otherwise known as trivalent passivation, and hexavalent chromium. GLMF still processes many parts with hexavalent chromium, but we have seen a push to use trivalent passivates on zinc plated parts. We prove to our clients that their specification requirements can still be achieved, if not surpassed, with these technological changes.

Why Hexavalent Chromium Has Been Used in the Past

Hexavalent chromium is remarkably versatile and exhibits many desirable and essential characteristics through numerous metal treatment process such as zinc electroplating. After its initial stage of dissolution, Hexavalent chromium then enters into a thick trivalent chromium layer that controls color, thickness and a “self-healing” property. Because of the “self-healing” property, soluble hexavalent chromium compounds will re-chromate any exposed areas when damaged. Finally, adsorption into the topcoat of the hexavalent chromate completes the process.

Great Lakes Metal Finishing offers hexavalent chromium upon request of the client. However, as the industry is changing due to information being released on the environmental impact of hexavalent chromates, many OEMs have changed their zinc plating specification requirements and have begun looking for suitable hexavalent chromium replacements. GLMF strives to educate clients on the benefits of using our trivalent passivates.

What’s Wrong with Hexavalent Chromium Based Passivation?

Hexavalent chromium based passivation is a well-established, easy-to-use technology that offers an attractive cost-to-benefit ratio. This coating is less expensive to apply and the production control requirements are extremely low. Nevertheless, the need to replace hexavalent chromium in the plating industry is gathering momentum.

The problem with hexavalent chromium compounds is that they can be environmentally hazardous. Because of the hazards associated with the compounds, it is beneficial to replace these products with environmentally friendly, commercially acceptable alternatives. GLMF offers alternatives to hexavalent chromium and guarantees that each finished zinc plated part will still achieve the highest quality with using an alternative to hexavalent chromium.  

Great Lakes Metal Finishing Offers Trivalent Passivates as an Alternative to Hexavalent Chromium

Great Lakes Metal Finishing has the capabilities to replace hexavalent chromium with various alternatives that have been proposed. More recently, today’s interest is focused upon the passivation process dealing with trivalent chromium compounds. In most respects, trivalent passivates closely resembles the characteristics of hexavalent chromium and is a suitable alternative. GLMF specializes in trivalent passivate processes for zinc plated parts. We offer various colors and other customizations to meet any end-users specifications.  

Great Lakes Metal Finishing has successfully performed clear, black, and yellow trivalent passivation films on electroplated zinc deposits for over 23 years. Over the years, we’ve achieved a balance between the increased material and process control costs by educating our clients on trivalent passivates longevity and color consistencies. Great Lakes Metal Finishing is known for producing high-quality zinc plated parts and surpassing the end-users expectations.

Why GLMF Primarily Uses Trivalent Chromate for Zinc Plated Parts

Many end-users have changed their zinc plating specification requirements in favor of the trivalent passivation process due to the imposed limitations on the number of hexavalent chromium compounds. Corrosion test numbers are significantly better for trivalent passivates over zinc than hexavalent chromium over zinc. Electrodeposits of zinc nickel represents the highest level of performance even after deposit post forming and heating. This means that the current end-user specification requirements can still be achieved with this formula change.

Disadvantages to Using Trivalent Chromate Passivation  

Some current issues with substituting trivalent chromium for hexavalent on zinc plated parts is that the colors are not identical, and there are no “self-healing” benefits due to the absence of soluble hexavalent chromium compounds. For the finisher using trivalent chromate passivation, the coating needs to be applied at elevated temperatures (30-60C), even so, this process remains relatively easy to operate.

Choose Great Lakes Metal Finishing for Trivalent Passivation

As evidenced by its increasing adoption, trivalent passivates as an intermediate stage is an ideal alternative to hexavalent chromium. GLMF specializes in trivalent passivation for zinc and yellow, zinc and clear, zinc and black, and other finishing processes to meet our customer’s specifications. We offer many plating methods for various industries and offer the best available technology while reducing excessive costs. When Great Lakes Metal Finishing uses trivalent passivates and applies it to a zinc alloy, it can achieve suitable or superior corrosion protection when compared to hexavalent chromium passivation.

Contact us today for all your trivalent chromate passivation needs!

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