Plating Bath Analysis Options with X-Ray Fluorescence (XRF)

One of the major applications of X-Ray Fluorescence (XRF) is quality control in coating thickness measurements. So, over our long history of providing XRF service and support, Eastern Applied Research has worked with a large number of metal finishers. In addition to coating thickness measurements, many of these metal finishers will have an interest in monitoring their plating baths because mistakes in bath ratios can result in a poor final product - blistering, off colors, and issues with the plated pieces when in use.

They have a few options for plating bath analysis - but what's the right option?

Some metal finishers will use chemical analysis methods like atomic absorption (AA) or inductively coupled plasma (ICP) for plating bath analysis. While these approaches can provide good performance in bath analysis, they also require a skilled operator and cost a good amount to maintain (chemicals, lamps, etc) over the life of the system. So, many metal finishers are interested in the options that XRF technology can provide in plating bath analysis.

Benefits of XRF in Plating Bath Analysis
The greatest benefit that XRF analyzers provide is that they don't require a highly skilled operator to get useful information, while AA and ICP do. With an appropriately configured XRF Analyzer, an operator would simply pull a bath sample into a sample cup, select the correct calibration/method, press a button, and get actionable information within seconds. Operators can quickly be trained in the steps involved.
 
While it won't match the lower levels of detection or number of elements seen with the other technologies, XRF can still provide a quick screening of baths and has much lower operating costs over the long-term when compared to AA or ICP.
 
Points to Consider
It's important to note that an x-ray fluorescence analyzer using a proportional counter detector will not provide as reliable performance for bath analysis interests as other options. Proportional counter detectors have historically been the most common detector for a wide range of coating measurement applications but bath analysis should use a more advanced detector (Si-PIN or SDD). These newer detector technologies can provide the peak resolution required to get reliable results.

Any XRF should really only be used to analyze major constituents (ie zinc quantification in a zinc bath).  Other technologies should be considered if any constituents beyond the major one is critical in a metal finishers analysis. However, as a screening device for major constituents, an appropriate XRF will perform well and the benefits of XRF make them a common tool on a shop floor or QC Laboratory.
 
XRF Analyzer Options for Bath Analysis
Your current XRF situation will dictate which of the following options you will want to review further.  Consider each and contact Eastern Applied to discuss your situation and the best approach to meet your needs.

Have an XRF Already? If your organization is currently using a proportional counter based XRF analyzer for coatings that is working well, then you may want to consider a dedicated XRF analyzer to meet your bath analysis needs.  While the Hitachi LabX5000 won't measure coating thicknesses, it should be a top consideration in this situation because of its spill proof design. Spills, as you may know, can be problematic on a more traditional coating thickness XRF analyzer (learn more about the LabX5000 by Hitachi High-Tech).

Hitachi LabX5000 for plating bath analysis

In addition to being spill proof, the LabX5000 is built with a hi-resolution detector so you can get good bath analysis while not having to deal with more involved technologies. It is fast, extremely simple to operate, and is built to last a long time in rugged environments.

If your current XRF is using a detector technology other than proportional counter (Si-PIN or SDD) then contact Eastern Applied Research as it may be possible to configure it for bath analysis interests too.

​Don't Have an XRF Analyzer Yet? If you are in the situation to look at newer XRF analyzers to do both coating thickness and bath analysis, then Eastern Applied would suggest the Hitachi XStrata920 with SDD technology. This analyzer (formerly known as the Oxford CMI900) is widely known for its reliability in coating thickness measurement applications and the Silicon Drift Detector (SDD) option makes it a good, versatile, tool for screening plating baths. While it isn't spill proof, the XStrata920-SDD is multi-functional - it can provide bath analysis and will also help you meet most coating thickness measurement needs, including electroless nickel applications (ENIG and ENEPIG) while also measuring phosphorous content and the increasingly common Zinc-Nickel (ZnNi) coating application.

Some results comparing an XRF dedicated to plating bath analysis (LabX5000) and a multi-use analyzer (X-Strata 920-SDD) follows, comparing performance on silver baths and zinc baths. As you can see, the performance is close on both models so it comes down to what is best for your situation.

Have any questions about XRF for bath analysis? Or, XRF in general?
​Then contact Eastern Applied Research.