Coatings & Linings

Coating of Faying Surfaces

This article discusses the challenges involved with coating contact, or “faying,” surfaces of steel building components that are bolted together. The use of certain zinc-rich primers is one successful solution, provided the primers meet required parameters for slip coefficient.

Painting at Night in the Gulf of Mexico

The heliport on a very large offshore structure required complete coating removal and replacement. The work could not be performed during daylight hours because of a very busy and crucial flight schedule, as well as safety concerns for the workers from paint debris and metal loss. This article describes the methods and materials used to perform the work during nighttime hours. The job was successfully completed in two weeks.

Preventing Mechanical Damage Makes Good “Cents”!

An excellent coating job can be ruined by mechanical damage during shipping and installation of the coated piece. Coating repairs can be time-consuming, expensive, and may yield an inferior coating job. This article provides precautions to be taken to minimize coating damage subsequent to initial coating.

Catastrophic Oxidation of Stainless and Nickel Alloys

Molybdenum-bearing stainless steels and nickel alloys can experience catastrophic oxidation. This occurs during oxidation of molybdenum-bearing materials and is caused by the action of molybdenum trioxide (MoO3) as an oxidation catalyst. This article explains the oxidation phenomenon and suggests ways to prevent it.

Effective Rehabilitation Planning for a Natural Gas Transmission Line—Part 1

This article describes the pipeline rehabilitation program developed by the natural gas transmission company in Colombia, South America. Part 1 presents the work accomplished to develop the Effective Rehabilitation Plan (ERP). Part 2 discusses the ERP in detail, including results and accomplishments.

Corrosion Control Technologies for Wastewater Treatment Plants

Wastewater treatment plant components generally experience both atmospheric and immersion corrosion. Hydrogen sulfide (H2S), which is usually present, has wide-ranging effects in wastewater systems, most notably causing corrosion and odor problems. The corrosion problems can be mitigated by a combination of strategies including judicious selection and implementation of emerging corrosion-resistant coatings.

Prevention of Micro-Flow Marks in Cathodic Electrodeposited Primer Coating in Automotive Industries

There was a defect of severe micro-flow mark lines in cathodic electrodeposited (CED) primer coating on car components. This problem was highlighted after final painting. This article describes the tests performed to determine the root cause of the defect. Tests included a surface profile of the CED coating and the determination of the microstructure and nickel content of the phosphate coating beneath the CED coating. The investigation identified the optimum concentration of nickel in the coating to refine phosphate grain size and create a unity crystal aspect ratio. It also found that the triple point junction of phosphate crystals determines the porosity to provide a uniform CED coating surface finish.

Role of Nonmetallic Composites in Gas Plants

Several factors cause deterioration of critical process equipment in process plants. The options widely utilized for restoration include conventional repair or replacement. Nonmetallic composite materials can be utilized as an option to restore equipment integrity. This article discusses the material degradation aspects in critical streams such as the cooling water system and hydrocarbon pipelines at a Saudi Arabian gas plant. Nonmetallic composite coating materials play a vital role in corrosion protection and life extension of core components.

Advanced Coatings for Water Treatment Plant Components

Components of water treatment plants (WTPs) are susceptible to corrosion from constant immersion in water and proximity to chlorine. A case history of corrosion problems and their treatment at an Army WTP is presented. Solutions included using high micro-silica restoration mortar and advanced coal tar epoxy coatings.

Premature Coating Disbonding on Ships and Offshore Structures

Epoxy/urethane coating systems are widely used for ships and offshore structures because of their excellent resistance to ultraviolet radiation and protection against corrosion. Recently, some of these coating systems used in Korea experienced premature failure. This work investigated the root cause of the failures using pH tests and Fourier transform infrared spectroscopy.

Effective Rehabilitation Planning for a Natural Gas Transmission Line—Part 2

This article outlines the results of a long-term pipeline integrity plan that was used to rehabilitate large segments of a natural gas pipeline over the past eight years. Part 1 of this article discussed the details to be followed in an effective rehabilitation plan to accomplish the goal of a well-maintained pipeline system.

Long-Term Performance of a Fluoropolymer- Lined Process Vessel

An ethylene chlorotrifluoro-ethylene (ECTFE) lining of a process vessel handling alkaline-based fluids and active chlorine was examined after more than 23 years of service. The examination and tests showed that the ECTFE material was undamaged. Test procedures, data evaluation, and conclusions are presented.

Amine Blush in Epoxy Coatings

Carbonated amine material, often called amine blush, is the reaction product of the amine functional curatives in epoxy paint with carbon dioxide (CO2) and water vapor. This article explains the formation of amine blush and discusses factors controlled by the applicator and those controlled by the paint manufacturer.

Restoration of a Brick Chimney with a Dual Lining System and Polymer Concrete

A brick flue at a generating station was in need of rehabilitation because of the spalling and cracking of the brick. This caused a leakage of acid gases into the annulus. A typical flash coat system was not desired because of its relatively short life. A system of corrosion-resistant materials, which has shown excellent performance and durability, was chosen to make the repairs. The system consists of a combination of organic and ceramic-based lining materials. A case history is presented, with descriptions of the operating environment and materials selection criteria.

Lining Prevents Biogenic Sulfide Corrosion In Wastewater Systems

Faced with serious concrete deterioration from biogenic sulfide corrosion within collection systems, engineers and municipalities are extending the service life of wastewater conveyance structures with the use of 100% solids polyamine systems designed for hydrogen sulfide (H2S) permeation resistance. This article explains how sewer interceptors, manholes, and lift stations were protected using fluid-applied linings.