A previously-published post, Can XRF Analyze Metal Coating Thickness? reviewed some of the metallic and non-metallic coatings used on metals to provide corrosion protection, impart strength and durability, and extend product lifetime. Coating materials include paint, zinc, cadmium, aluminum, chrome, nickel, nickel-chromium, iron oxide, and silver. A related post on Producing Polymers and Plastics examines another useful metal coating material– powder coatings.
Powder coatings may be thermoplastics or thermoset polymers applied as freeflowing, dry powder. Like their metal counterparts, powder coatings also play a major role in the automotive, aerospace, medical device, construction, and electronics industries. Powder coatings can replace paint coatings on all kinds of metal appliances, transport vehicles and parts, metal electrical equipment, lawn and garden tools, metal furniture and more. Newer technologies allow for other materials, such as medium density fiberboard (MDF), to be powder coated using different methods.
Powder coatings work with standard metal coating processes such as hot dip galvanizing as a final finish. The metal is pretreated prior to powder coating application. According to an article published in Products Finishing, petreatments most often used in powder coating are iron phosphate for steel, zinc phosphate for galvanized or steel, and chromium phosphates for aluminum substrates. New pretreatment technologies use transition metals, organo-metallic materials, or other alternatives that can be applied with little or no heat and are less prone to sludge buildup in the pretreatment bath than conventional iron or zinc phosphate formulations. Other advances include non-chrome seal systems, which can yield improved corrosion protection on steel, galvanized steel and aluminum alloys. Dry-in-place pretreatment products, such as a seal rinse over an alkali metal phosphate, can reduce the number of stages required before powder coating application. Chrome dried-in-place treatments are effective on multi-metal substrates, and may be the sole pretreatment required for some applications.
Read How Do Powder Coatings Compare with Paint to learn more about thermoplastic and thermoset powder coatings and how measurement of the rheological properties of powder coatings will help ensure that the correct powder coating formula is used for its intended application. Read XRF in the Aerospace Industry: Applications in Coating Analysis, XRF Drives Coating Analysis in the Automotive Industry, and Quality of Galvanized Steel Might Depend on Zinc Coating Weight to learn more about technologies to analyze metal coating thickness.
Additional Resources:
- Download our free eBook: A Practical Guide to Improving Steel Manufacturing Processes and Production Methods
- Visit our center for Improving Steel Manufacturing Processes and Production
Can XRF analysis measure the thickness of the nitride layer on the surface of nitrided 304 SS?
Thank you for the question, Bill. My in-house expert says:
Nitriding is a heat treating process that diffuses nitrogen into the surface of a metal to create a case-hardened surface. It is not possible to determine coating thickness of nitrogen with a handheld XRF analyzer. Nitrogen is very light element and its XRF signal is too weak to be able to measure it with handheld XRF. Lightest element in periodic table that can be analyzed with handheld XRF is magnesium. In some cases it is possible to determine coating thickness based on how it will influence the XRF signal from substrate, but typically nitride layer is too thin for this approach.
Hope this helped.
One of the main benefits of powder coating is that it protects metal from corrosion. The process for powder coating can be quite intricate and difficult if you don’t know what you are doing. Also, more than just metal can be painted.
Thank you for your comment, Sam. Yes, more than metals can have coatings. We talked about metals because this is the Analyzing Metals blog. There are additional coatings-related articles on our Producing Polymers & Plastics blog as well: https://www.thermofisher.com/blog/?s=coatings&cat=1803
My wife and I live in a very cold climate. There is always tons of salt on the roads in the winter time, and that salt can corrode metal on your car. I didn’t realize that powder coating was able to improve the corrosion rate on steel, galvanized steel and aluminium alloys. That seems like something our cars could really benefit from.
Yes, Tomas, the automotive industry uses coatings on cars to help prevent corrosion. Here is some more information on it: Paints, Coatings & Adhesives
Thank you for informing me that powder coating coats metals as a dry, powdery substance, and it is great on many technological parts. About a week ago, I was driving past an old factory and noticed that all the equipment looked stripped and rusted. I would think that I would want my equipment to stay nice so that it would last longer. I wonder if there are services that could help with stuff like that.
Maybe our readers have suggestions?
But how can metal finishing helps with corrosion?
Hi Justin– Maybe these articles can help you understand how coatings and finishes matter when it comes to corrosion: http://www.acceleratingscience.com/metals/can-xrf-analyze-metal-coating-thickness/ and https://www.thermofisher.com/blog/metals/unique-sensor-design-accurately-measures-zinc-coating-weight-on-galvanized-steel/
What if we hire PB Metal for the same?
Great information of Powder Coatings it’s very usefull for me.
any more information to visit us: https://www.reportsanddata.com/report-detail/chromium-powder-market