Beyond TSA - The Rise of Aluminium Flake Silicone Coatings - in High-Temperature CUI Applications and Wellhead Casing Protection

Sep 18, 2026

Uploaded by Noah

More than four decades of oil & gas and petrochemical operations have faced high maintenance costs, plant outages, and severe failures driven by corrosion under insulation (CUI) on insulated pipes, tanks, and vessels. The paper presents CUI-mimicking laboratory results for a liquid-applied aluminium flake-filled silicone coating and for a metallic thermal spray aluminium (TSA) coating. Laboratory findings are used to predict real-world performance from case histories, including 20 years of CUI mitigation and 10 years of corrosion protection in high-temperature immersion service for oilpatch wellheads.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages7

Reading Time18 min

AccessFree to download

Abstract

Introduction

Key questions for CUI mitigation

Mechanisms of action: IMM coating containing aluminium flake pigments

Buffering pH and cathodic inhibition

Inspiring Colourful Futures Technical Paper Technical Paper Beyond TSA-The rise of aluminium flake silicone coatings in hightemperature CUI applications and wellhead casing protection Mike O’Donoghue, Vijay Datta, Douglas Beaumont, Darren Ward, Toby Stein, International Paint LLC.; Nicole de Varennes, Vision Integrity Engineering Abstract For more than four decades the oil & gas and petrochemical industries have had to contend with high maintenance costs, plant outages and sometimes catastrophic infrastructure failures caused by corrosion under insulation (CUI) of insulated pipes, tanks and vessels. This article highlights how coating manufacturers have done superbly wellin formulating silicone high temperature‑ resistant coatings to protect thermally insulated critical structures from the ravages of CUI. Results are presented of CUI‑simulating laboratory tests of a liquid‑ applied aluminium flake‑filled silicone coating and a metallic thermal spray aluminium (TSA) coating. The test results have value in terms of predicting the liquid coating’s real‑world performance for case histories provided, namely 20 years of CUI mitigation in the oil and gas industry and 10 years of corrosion protection in mostly high temperature immersion service on oilpatch wellheads. Introduction CUI is a particularly aggressive degradation mechanism for asset owners. Localised corrosion and pitting occur when thermal insulation traps moisture and contaminants on steel surfaces. Similar but not identical to immersion conditions, micro‑environments beneath insulation include the presence of dissolved oxygen, moisture and concentration of soluble chlorides, and numerous temperature scenarios, viz, high or low temperature, repetitive thermal cycling, different rates of temperature change, and thermal shock1. High‑performance silicone temperature resistant coatings, often described as inert multi‑polymeric matrix (IMM) coatings, are single‑component (1K) or two‑component (2K) inorganic coatings that exhibit high heat and cryogenic resistance, respectively up to 650°C (1202°F) and down to ‑ 196°C (‑321°F). They have also been shown to provide broad anticorrosion performance at ambient and high temperature for harsh environments when tested according to ISO 12944‑6:2018 (CX being the highest corrosion category for extreme environments) or exposed to real world CX conditions2. Some mechanisms of action are discussed for an aluminium flake‑filled IMM liquid‑ applied coating and a metallic TSA coating applied to carbon steel pipes. The ISO19277:2018 Houston Vertical Pipe Test was employed to simulate certain CUI conditions where temperatures cycled between 96°C (205°F) and 446°C (835°F)3,4 . High‑performance coatings for CUI mitigation need to have the right balance of heat resistance, anticorrosive properties and flexibility. According to NACE SP0198 the critical corrosion temperature ranges that a high heat coating must withstand are ‑4°C (25°F) to 175°C (347°F) for carbon steel, and 50°C (122°F) to 175°C (347°F) for stainless steel5. Industrial and marine process assets that operate at high or low temperatures often require corrosion protection for steel vulnerable to CUI or chloride‑induced external stress corrosion cracking (ESCC) . As a result, carbon steel coated with IMM coatings or TSA is often specified when CUI temperatures range from ‑ 196°C (‑321°F) to 650°C (1202°F) . Against this backdrop, the following key questions are of interest: 1. For CUI mitigation, what is better as the last line of defence: a liquid applied aluminium flake‑filled IMM coating or TSA for corrosion protection and long‑life coating performance? 2. Do the aluminium‑flake pigments inan IMM coating enhance the coating’s reliability and predictability of success for decades of CUI mitigation in cyclic temperature service? 3. Could the same aluminium flake‑ filled IMM coating deliver 10‑years corrosion‑free performance for immersion service on

FAQs

What problem does the paper address regarding oil & gas assets?

It addresses corrosion under insulation (CUI) that causes localized corrosion, pitting, and can lead to major infrastructure failures.

Which coatings are evaluated in the study?

The paper evaluates a liquid-applied aluminium flake-filled silicone coating and a metallic thermal spray aluminium (TSA) coating.

How does aluminium flake pigment contribute to corrosion protection in IMM coatings?

The aluminium flakes are described as electrically inert at the coating–substrate interface and their incorporation helps mitigate cathodic disbondment by lowering local pH through reactions in aqueous NaCl environments.

Sep 18, 2026

Uploaded by Noah