Effectiveness of Water Spray Test on Thermal Spray Aluminum Coating

Abstract Thermal spray aluminum (TSA) coating is widely recognized for its durability and exceptional anticorrosive properties, and it is extensively utilized in surface protection of both onshore and offshore oil and gas facilities. Some end-users and international standards specify a water spray test, or similar tests, to detect the possible presence of low thickness areas. This study was inspired by a case where a water spray test had initially passed, but later rust developed after a few months of atmospheric exposure. Subsequent investigation identified multiple areas with insufficient coating thickness, raising concerns regarding the water spray test’s effectiveness in detecting such deficiencies. In this investigative study, a series of water spray tests were conducted under various simulated conditions that included different coating thicknesses, water qualities, and methods of water spraying to understand the critical factors that affect the efficacy of the water spray test. By adopting insights from this study, the identification of low thickness areas can be enhanced enabling timely repair and improved overall quality of TSA applications thereby avoiding premature rusting failure of the substrate.