Coatings & Linings

Inorganic Zincs—How Do They Cure?

Inorganic zinc (IOZ) coatings are used pervasively in industry to provide reliable protection from corrosion on a variety of substrates. Problems have emerged with coatings applied over zinc primers, however, such as delamination and blistering. This article discusses proper curing methods for IOZs to ensure dependable performance of the entire coating system.

Importance of the ‘Little Things’ in a Good Coating Job

Many years ago, early in my career, I was reminded that it’s the little things that make a standard paint job a good paint job. Coatings are too often thought of as something that must be done, but it’s not necessary to spend much time on surface preparation or application. After all, “paint is paint and anybody can apply paint.”

Service Life Extension for Protective Coatings

Because of increasing costs, owners are demanding longer coating service life. Ten to 15 years is no longer satisfactory. Simply adding dry film thickness will not work since many coatings crack at excessive thicknesses. Recent coating technology advances permit the use of solvent-free epoxy and polyurethane systems having >15-year lives. Newer combinations of epoxy and polysiloxane resins will make a 25-year life achievable.

Predicting Coating Life

The prediction of coating life depends on many factors, including the coating system used, preparation and application methods, and the severity of the environment. This article describes the knowledge needed to estimate coating life and the conditions that can compromise coating systems.

The Importance of the Pre-Job Meeting

A thorough pre-job meeting is an essential part of any project. This article covers the requirements of a pre-job meeting before starting a coating project. It presents advice on who should attend, the roles of the attendees, and references needed.

Managing a Coating & Plating Supply Chain

Re-engineering supply chains can reduce costs, cut delivery times, provide a significant competitive advantage, and enhance customer relationships. Supply chain concepts can be applied to the finishing phase (coating or plating) of production to further cut costs and delivery times.

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.