Today, the global automotive market is strong. The demand is already high, and the market is expected to reach $27.69 billion by 2022. In developing countries, increased car sales (as well as new coating technologies) are guaranteeing suppliers of coatings and metal finishing processes many commercial opportunities in the coming years. However, the inevitable drive for environmental efficiency, including reduction targets of energy and water usage, is going to impact the industry’s current methods.
Car pre-treatment conversion coatings is one area that is already undergoing widespread change. The industry is moving away from phosphate-based coatings, and heading in the direction of zirconium and titanium-based chemistries.
The Advantages of Zirconium-Based Conversion Coatings
Zirconium-based coatings are steadily replacing their predecessors as they offer vast environmental, cost and handling advantages over the traditional iron and zinc phosphates. Below is a list of the main benefits of the alternative pre-treatment chemistry.
Uses Less Energy
Conventional iron-phosphate processing requires heat for both the cleaning stage and for the coating stage itself. When using zirconium, it is only the cleaning stage that is heated; as the coating occurs at room temperature. This reduction in heat makes for reduced energy costs, which lowers the process’s carbon footprint.
Most zirconium-based products for pre-treatment do not have phosphates within them. Waste cannot be discharged without depositing significant amounts of phosphates into public waste systems, which are heavily legislated. Removing phosphates from the process therefore minimizes the costs of hazardous waste disposal.
Extremely Low Coating Weights
Compared with iron phosphate and zinc phosphate, the coating weights of zirconium-based treatments are extremely low. The typical conversion coating thicknesses are a few to hundreds of nanometers.
Reduced Water Use
A conventional iron-phosphate process relies on huge volumes of water for the rinsing stages as well as the evaporating stages. While zirconium-based processes are still reliant on a reasonable quantity of water, they can use far less as they use a counter-flow system for the rinsing stages.
Fewer Hazardous Substances
As well as being free of phosphates, these zirconium coatings are not reliant on hazardous substances, which makes them much safer for operators. Unlike zinc and iron phosphates, which rely on accelerators to attain a uniform coating, the majority of zirconium coatings do not require accelerators.
Measurement of Zirconium Thickness by XRF
To prevent corrosion and provide a suitable surface for paint or coating, it is important to obtain a consistent thickness of the ultra-thin zirconium layer. X-ray fluorescence (XRF) analysis is fast, precise and non-destructive, which makes it the best way to measure the thickness.
The standard test method for measuring zirconium treatment weight or thickness on metal substrates by X-ray fluorescence is ASTM D7639. Hitachi’s X-MET8000 helps you conform to ASTM D7639, which allows you to create a reliable and high-quality process.
The X-MET8000 is simple and efficient to use. Battery operated, it is a hand-held XRF analyzer contained within a robust, heavy-duty design. These features make it perfect for industrial applications such as car coating pre-treatment processing.
The user simply must ‘point and shoot’ with the device, and it can give you an instant and accurate reading. This quality makes it ideal for the in-line analysis of coat weights during any production stage production.
A further benefit of the X-MET8000 is that it doesn’t require a vast amount of sample preparation. Certain XRF analyzers need the user to cut the sample, or acid-strip and subsequently detect the amount of zirconium present within the acidic solution. With this equipment, none of this user-based work is necessary. To measure, the operator can place the nose directly against the panel and press the trigger. The results will appear on the screen in a matter of seconds.
This information has been sourced, reviewed and adapted from materials provided by Hitachi High-Tech Analytical Science.
For more information on this source, please visit Hitachi High-Tech Analytical Science.