Search Results for metal-line corrosion

This article presents a detailed examination of corrosion at the various production stages of wafer fabrication. The corrosion issues related to batch metal-etch systems and single-wafer metal-etch systems are also discussed. The article provides a case study, which illustrates that the factors outside the normal processing of wafers or tool-specific problems can contribute to metal-line corrosion.

Stray-current corrosion is an accelerated form of corrosion caused by externally induced electric current. It can occur in unprotected pipelines and submerged metal structures located near electric power sources or anywhere voltage differences exist. This article describes common scenarios and sources of stray current along with ways to detect it and prevent the type of corrosion it can cause.

This article focuses on the internal corrosion of iron and copper in potable water. It tabulates the corrosion and water-quality problems caused by materials in contact with drinking water. The article provides a theoretical description of the reduction-oxidation reactions in water to analyze the causes of corrosion of metals in contact with water. It discusses the Langelier saturation index and the Larson index for determining corrosion in potable water systems. The article describes the two major ways of mitigation against corrosion in potable water systems. The first is to line the pipe surface physically such that water and dissolved oxygen cannot reach the metal surface and the second is to add chemical inhibitors to alter water chemistry.

Corrosion resistance can usually be maintained in the welded condition by balancing alloy compositions, shielding molten and hot metal surfaces, and choosing the proper welding parameters. This article describes some of the metallurgical factors that affect corrosion of weldments. It also reviews the considerations for selected nonferrous alloy systems such as aluminum, titanium, tantalum, and nickel.

This article provides a brief discussion on the common types of overlayers that can be used on a metal surface to protect it from corrosion. These overlayers include phosphate, chromate, and chromate-free conversion coatings; hot dip galvanizing; cementitious linings; glass and porcelain enamels; electroplating; thermal spray coatings; and rubber linings.

Weldments exhibit special microstructural features that need to be recognized and understood in order to predict acceptable corrosion service life of welded structures. This article describes some of the general characteristics associated with the corrosion of weldments. It emphasizes the role of macrocompositional and microcompositional variations to bring out differences that need to be realized in comparing corrosion of weldments to that of wrought materials. The article concludes with a discussion on important welding practices used to minimize corrosion in weldments.

Hydrochloric acid (HCl) may contain traces of impurities that will change the aggressiveness of the solution. This article discusses the effects of impurities such as fluorides, ferric salts, cupric salts, chlorine, and organic solvents, in HCl. It describes the corrosion resistance of various metals and alloys in HCl, including carbon and alloy steels, austenitic stainless steels, standard ferritic stainless steels, nickel and nickel alloys, copper and copper alloys, corrosion-resistant cast iron, zirconium, titanium and titanium alloys, tantalum and its alloys, and noble metals. The article illustrates the effect of HCl on nonmetallic materials such as natural rubber, neoprene, thermoplastics, and reinforced thermoset plastics. It also tabulates the corrosion of various metals in dry hydrogen chloride.

The major benefit of the implementation of the corrosion-control technologies at Army installations is the extension of the service life of buildings and other structures. This article reviews the exposure of military facilities and equipment to a wide variety of environmental conditions, including soils, waters, or atmospheres of varying corrosivity. It presents the case studies illustrating typical examples of the types of corrosion problems found on military installations. The article describes the various corrosion-control technologies used in military facilities. These include protective coatings and linings, cathodic protection, advanced materials selection and design, water treatment, equipment inspection and monitoring, and below-grade moisture mitigation.

This article discusses the materials of construction found in pharmaceutical production facilities. The materials discussed are different stainless steels, nickel and nickel-base alloys, titanium, zirconium, impervious graphite, fluoropolymers, and glass-lined steel. The article describes the three primary causes of failure in the manufacture of pharmaceuticals: embedded iron, failures of glass linings, and corrosion under thermal insulation.

This article describes the eight chemical cleaning methods, namely, circulation, fill and soak, cascade, foam, vapor-phase organic, steam-injected, on-line chemical, and mechanical cleaning. It presents information on deposit types, solvents used to remove them, and construction material incompatibilities in a table. The article summarizes the uses of chemical cleaning solutions, including hydrochloric acid, phosphoric acid, and sulfamic acid, as well as the additives used to neutralize their impact on corrosion. It discusses the chemical cleaning procedures, including selection of cleaning method and solvent, documentation of cleaning, and corrosion monitoring in chemical cleaning.

Pitting is a form of localized corrosion that is often a concern in applications involving passivating metals and alloys in aggressive environments. This article describes the test methods for pitting corrosion. These methods include ASTM G 48, ASTM F 746, ASTM G 61, ASTM G 100, and electrochemical noise measurements. The visual examination, metallographic examination, and nondestructive inspection of pits are discussed. The article reviews the procedures for the use of standard charts, metal penetration, statistical analysis, and loss in mechanical properties to quantify the severity of pitting damage.

This article describes the mechanisms of differential corrosion cells corrosion, microbiologically influenced corrosion, and stray direct current corrosion. It discusses the most common causes and contributing factors for corrosion and stress-corrosion cracking, as well as prevention, mitigation, detection, and repair processes.

Two-component polyurea elastomeric coating/lining systems are the newest technology in the protective coating/lining industry and a wide variety of applications have been developed. These include coating/lining applications over concrete, geotextile membranes, various metals for corrosion and decorative areas, and some plastics. This article discusses the formulation basics of polyurea technology and compares the technology to that of polyurethane and polyurethane/polyurea systems. It addresses performance issues and describes application processing considerations and safety practices of polyurea coating/lining systems.

This article provides a discussion on the operation of various methods and sensors that have been used or have the potential to be used for on-line, real-time monitoring of localized corrosion. These include the electrochemical noise (ECN) method, nonelectrochemical methods, the galvanically coupled differential flow cell, galvanically coupled crevice cell, coupled multielectrode sensor, and electrochemical biofilm activity sensor.

This article provides a general introduction to the kinetics of aqueous corrosion with an emphasis on electrochemical principles. It describes the thermodynamic basis for corrosion by determining the equilibrium potentials of electrochemical reactions from the Nernst equation. A corrosion process can be controlled by the electronic conductivity of passive films when the cathodic reaction occurs on the surface of the film and by activation control of corrosion. Passivation becomes thermodynamically possible when the corrosion potential exceeds the potential corresponding to the equilibrium between a metal and one of its oxides/hydroxides. The article schematically illustrates a current-potential or polarization curve for an anodic process.

A potential pH diagram is a graphical representation of the relations, derived from the Nernst equation, between the pH and the equilibrium potentials (E) of the most probable electrochemical reactions occurring in a solution containing a specific element. This article describes three types of reactions for calculation and construction of E-pH diagrams: electrochemical reactions of pure charge (electron) transfer; reactions involving both electron and solvated proton transfer; and acid-base reactions of pure solvated proton transfer. It illustrates the practical use of E-pH diagrams for temperature aqueous solutions and adsorbed species and in prediction of corrosion of nickel and copper.

This article provides information on the municipal wastewater system components such as piping, pump stations, headworks, clarifiers, aeration structures, digesters, biosolids dewatering equipment, and sludge stabilization. It explains the major corrosion damage mechanisms to which those component parts of the system are exposed. It presents useful guidelines for selecting and using protective coatings in municipal sewerage collection systems and water reclamation facilities in wastewater treatment plants. The article includes annotated flow diagrams of a wastewater collection system, wastewater treatment plants, and spreadsheets listing the most widely used generic coating systems by structure and substrate material. It concludes with a section on quality watchouts when selecting or using protective coatings in municipal wastewater systems.

This article discusses the effects of parameters on corrosivity and explains why it is critical to examine the parameter interactions prior to capturing the synergistic effects of the parameters on corrosion. It examines the methods of internal corrosion prediction for multiphase pipelines. The article reviews methodologies to perform internal corrosion direct assessment for pipelines. Real-time monitoring techniques for assessing actual corrosion at critical locations are discussed. The article also presents the case studies for multi-technique electrochemical corrosion monitoring.