Coatings for corrosion and wear resistance
If a metal was used in its raw manufactured state, then very quickly many things would happen. It would start to corrode, look unsightly, and for moving parts immediately wear away or even shatter. To overcome all of these, a range of metallic coatings are applied to the base metal, to ensure good appearance and long in-service life.
For decorative finishing, chrome is often coated onto nickel. The chrome gives both corrosion resistance and a decorative finish and is widely used for automotive trims, e.g. car badges, and bathroom accessories such as taps, showers etc. For wear resistance titanium is coated on steel and examples include high speed tool drills.
By far the widest application is for corrosion resistance where zinc is applied to a range of materials which are both metallic, e.g. iron base and non-metallic e.g. plastic base. A vast range of fastenings, such as rivets, nuts and bolts, clips etc all require a zinc coating to ensure long in-service life.
Generally metallic coatings of gold, silver, chromium, copper, nickel, tin, zinc can be applied either as a single layer or multi-layers, and in all cases careful control of the layer thickness is required to ensure the coating has been applied evenly and cost-effectively.
The CMI900 is a simple to use, compact, field proven, benchtop Energy Dispersive X-ray fluorescence (EDXRF) system tailored to measure a range of metallic coatings. Coating thickness measurements using EDXRF offers many benefits including: simple or no sample preparation, no potentially hazardous chemicals, no weighting or volumetric measurements, and fast analysis. The sample is simply placed on the tray, aligned using the in-built camera (allowing the measurement of small areas of the sample), and pressing Go. Results appear in seconds offering simple quality control analysis with associated cost optimisation, and the instrument operated by production staff on a 24/7 basis.
The X-Strata980 is the highest performance instrument for coating thickness and chemical composition, with additional flexibility measuring the RoHS (Restriction of Hazardous Substances) elements. The X-Strata980 offers the same benefits as CMI900, but in addition by having a larger sample chamber allows the measurement of very large parts. The higher power X-ray tube also offers multi-layer analysis, e.g. silver plated onto nickel on a copper base.
In all cases optimised application specific solutions are available for all types of metallic coating thickness measurements.