Analysis of Lead Paint
Service Sector – Environmental, Techniques used – ICP, SEM-EDX
A conservation organisation was involved in the refurbishment of a gas holder, dating back to pre-1970, when use of lead paint was restricted. The holder had been painted many times; we were supplied with samples of paint and asked to determine if lead was present. An average lead-value was taken for the sample by preparing it via microwave-acid digestion and analysing it via inductively-coupled plasma optical emission spectroscopy (ICP-OES) by creating atomic ions. Lead was found to be present.
We also freeze-fractured samples and investigated each layer by energy dispersive X-ray (EDX) analysis - which creates a signal based on energy dispersed by elements present in the sample. EDX allowed us to confirm which layers of paint contained lead and which didn’t – allowing for safe removal.
INVESTIGATION INTO STEEL - SURVEYING WETTABILITY
Service Sector – Marine Surveying , Techniques used – SEM-EDX
A marine insurance company had a cargo of galvanized steel which was wetted during shipping and rusted. It was important to find whether the wetting was a result of fresh or saltwater exposure – indicating if the exposure occurred on land or at sea. If wetting had occurred at sea, the dry samples we received would contain residual sodium chloride salts.
The EDX attachment of the scanning electron microscope (SEM) was utilised as it is sensitive to heavier elements like chlorine. The EDX spectrum showed no chlorine was present, neither was sodium. This concluded wetting could not have occurred at sea enabling the client to identify the parties responsible for their insurance claim.
Material Failure Analysis
Service Sector – Materials , Technique used – SEM-EDX
A Hull-based company came to us with failing stainless-steel filter meshes due to excess corrosion. Investigating this failure, samples of the corroded filters were analysed by Scanning Electron Microscopy (SEM) with an Energy Dispersive X-Ray Diffraction (EDX) attachment. The high magnification SEM images showed corrosion from a deposited material on the filter. Elemental analysis via the EDX attachment confirmed the deposit to include copper (Cu) – a known accelerant for stainless-steel corrosion, leading to premature failure. Copper was not present in the raw materials used in manufacturing. These results lead the company to investigate its source, potentially arising from copper piping which they had been unaware of.
Chemical Protective Suits
Service Sector – Chemical Industry
As part of a KTP with Microguard– a hull-based company who manufacture chemical protective suits which require extensive permeation testing. They were using a third-party for this but decided to bring it in-house.
Initial trial work was carried out in the Department of Chemistry’s laboratories before building a testing laboratory from scratch at Micrograd’s Hull site. At the end of the two years, Micrograd were in possession of a major facility which was not present before and the KTP program received the highest grade of “Outstanding”.
Micrograd has since been taken over by the Ansell Group, who stated the testing laboratory in Hull was a prime factor in their decision.