Ensuring the long-term protection of parts exposed to the extremely harsh conditions found in offshore environments requires specialized anti-corrosion coatings. For example, thermal spray aluminum (TSA) – used to protect stainless steel against corrosion even at high temperatures – can withstand marine influences for decades. However, to achieve such longevity, the TSA must have a certain coating thickness, making quality inspections mandatory.
Thermal spraying techniques are very effective for applying thick layers over large areas, as the hot coating materials are literally squirted onto the surface. Compared to other coating processes the rates of deposition are high: the aluminum is fed in wire form, molten and accelerated as micrometer-sized particles towards the substrate, forming a tough, protective casing. The TSA coatings used in the oil and gas industry are typically between 10 and 20 mils (250 - 500 µm); layers this thick can only be measured using the phase sensitive eddy current method. Controls are usually performed either right after the coating process or during maintenance to monitor the progress of corrosion and to determine whether parts should be recoated.
The thickness of thermal spray aluminum (TSA) coatings – protecting offshore stainless steel and steel constructions and other parts exposed to corrosive salt water and harsh environmental conditions – can be measured easily and effectively using FISCHER’s PHASCOPE® PMP10 with the ESD20-TSA probe. For further information please visit FABTECH Booth # C47026 or www.protective-coating-inspection.com or contact your local Fischer representative.