Although aluminum alloys are inherently corrosion resistant, there are many operating environments where they require additional protection. This article describes the conditions under which aluminum is prone to corrode and explains how to prevent it through the addition of conversion coatings and paints. It addresses some of the more common corrosion mechanisms, including corrosion driven by pH extremes, pitting corrosion, crevice corrosion, galvanic corrosion, and filiform corrosion. The article also describes in-plant as well as field application procedures for cleaning and coating, and discusses the advantages and limitations of the various materials and chemicals used.

Cast irons provide excellent resistance to a wide range of corrosion environments when properly matched with that service environment. This article presents basic parameters to be considered before selecting cast irons for corrosion services. Alloying elements can play a dominant role in the susceptibility of cast irons to corrosion attack. The article discusses the various alloying elements, such as silicon, nickel, chromium, copper, and molybdenum, that enhance the corrosion resistance of cast irons. Cast irons exhibit the same general forms of corrosion as other metals and alloys. The article reviews the various forms of corrosions, such as graphitic corrosion, fretting corrosion, pitting and crevice corrosion, intergranular attack, erosion-corrosion, microbiologically induced corrosion, and stress-corrosion cracking. It discusses the four general categories of coatings used on cast irons to enhance corrosion resistance: metallic, organic, conversion, and enamel coatings.

This article reviews the corrosion interactions between biomedical alloys, in particular iron-base, titanium-base, and cobalt-base alloys, in complex geometries and in applications where there are significant cyclic stresses and potential for wear and fretting motion. It discusses the nature of these metal surfaces and their propensity for corrosion reactions when combined with similar or different alloys in complex restrictive environments within the human body and under loading conditions. The article describes the factors that influence mechanically assisted crevice corrosion. It reviews the tests developed to investigate the aspects of mechanically assisted corrosion of metallic biomaterials: the scratch test and the in vitro fretting corrosion test.

This article discusses the commonly encountered forms of automotive body corrosion. The corrosion forms include general or uniform corrosion, cosmetic or under-film corrosion, galvanic corrosion, crevice corrosion, poultice or under-deposit corrosion, and pitting corrosion. Corrosion-resistant sheet metals, such as electrogalvanized steel, hot dip galvanized steel, and hot dip galvannealed steel, are reviewed. The article provides information on the paint and sealant systems for corrosion control in automotive body applications.

This article begins with a discussion on the components and importance of flue gas desulfurization (FGD) technology used in power plant for pollution control. It further discusses the corrosion problems encountered in different operating zones of FGD system and the major forms of corrosive attack encountered in those zones, including crevice corrosion, pitting corrosion, and acid attack. The article concludes with information on the materials selection and design features for minimizing the possibility of corrosion.

This article reviews the understanding of corrosion interactions between alloys in complex geometries and in applications where there are significant cyclic stresses and potential for wear and fretting motion. These alloys include iron-base, titanium-base, and cobalt-base alloys. The article discusses the surface characteristics and electrochemical behavior of metallic biomaterials. It summaries the clinical context for mechanically assisted corrosion and describes mechanically assisted crevice corrosion. There have been several tests developed to investigate aspects of mechanically assisted corrosion. The article also explains the scratch test and the in vitro fretting corrosion test.

Steel automotive exhaust systems suffer from various forms of corrosion. This article illustrates exhaust system components with typical upper metal skin temperatures and alloys of construction. It discusses high-temperature corrosion of automotive exhaust systems, including oxidation, hot salt attack, and thermal fatigue. The article describes the various forms of corrosion which occur at the cold end of an exhaust system. The forms of cold end exhaust corrosion, including condensate pitting corrosion, exterior salt pitting, crevice corrosion, intergranular corrosion, and galvanic corrosion.

Advances in vehicle design and technology require engine coolant technology to minimize the degradation of nonmetals and prevent the corrosion of the metals in the cooling system. This article provides a detailed discussion on the functions, operation, materials, and major components of the cooling system. It discusses various forms of corrosion that occur in cooling systems, including uniform corrosion, galvanic corrosion, crevice corrosion, pitting corrosion, intergranular corrosion, erosion corrosion, and cavitation corrosion. The article presents information on engine coolant base components and inhibitors used for corrosion prevention. It reviews the coolant performance tests recommended by ASTM, SAE, and vehicle manufacturers. The article concludes with a description on the difference between light-duty automotive and heavy-duty diesel engine coolants.

This article provides an overview of the principle forms of corrosion that can occur on automotive aluminum components and offers general guidelines on how best to avoid these situations. It discusses the most common forms of aluminum corrosion such as stress-induced corrosion, cosmetic corrosion, crevice corrosion, and galvanic corrosion.

Corrosion, fatigue, and their synergistic interactions are among the principal causes of damage to aircraft structures. This article describes aircraft corrosion fatigue assessment in the context of different approaches used to manage aircraft structural integrity, schedule aircraft inspection intervals, and perform repair and maintenance of aircraft in service. It illustrates the types of corrosive attack observed in aircraft structures, including uniform, galvanic, pitting, filiform, fretting, intergranular, exfoliation corrosion, and stress-corrosion cracking. The article discusses geometric parameters such as pit dimensions, surface roughness, loss of metal thickness, and volume increase due to pillowing to quantitatively characterize the types of corrosion. It also explains the two most common fatigue life assessment methods used in the military aerospace industry: fatigue crack initiation and crack growth analysis.

This article reviews the generator industry experience with stress-corrosion cracking of 18Mn-5Cr alloy retaining rings. It provides a description of corrosion of magnetic retaining rings. The article also discusses the primary repair alternatives to address crevice-corrosion cracking in water-cooled generators.

This article describes the commonly observed forms of airplane corrosion, namely: general corrosion, exfoliation corrosion, pitting corrosion, microbiologically induced corrosion, galvanic corrosion, filiform corrosion, crevice corrosion, stress-corrosion cracking, and fretting. It discusses the factors influencing airplane corrosion from the manufacturing perspective: design, manufacturing, and service-related factors. The article explains the collection of corrosion data and provides an overview of the implementation and evolution of airline corrosion prevention and control programs and directions being considered in the design for corrosion prevention of airplanes.

This article describes the corrosion of principal parts of mining equipment such as mine shafts, wire rope, rock bolts, and pump and piping systems. It discusses the diagnosis and prevention of various types of corrosion including uniform corrosion, pitting corrosion, crevice corrosion, erosion-corrosion, and intergranular corrosion. The article explains the corrosion in tanks, reactor vessels, cyclic loading machinery, and pressure leaching equipment.

This article describes the processes involved in the production of hafnium and its alloys. It discusses the physical, mechanical and chemical properties of hafnium. The aqueous corrosion testing of hafnium and its alloys is detailed. The article reviews the corrosion resistance of hafnium in specific media, namely, water, steam, hydrochloric acid, nitric acid, sulfuric acid, alkalis, organics, molten metals, and gases. Forms of corrosion, namely, galvanic corrosion, crevice corrosion, and pitting corrosion are included. The article explains the corrosion of hafnium alloys such as hafnium-zirconium alloys and hafnium-tantalum alloys. It also deals with the applications of hafnium and its alloys in the nuclear and chemical industries.

This article provides an overview of the identification systems for various grades of wrought stainless steels, namely, the American Iron and Steel Institute numbering system, the Unified Numbering System, and proprietary designations. It elaborates on five major families of stainless steels, as defined by the crystallographic structure. These include ferritic stainless steels, austenitic stainless steels, martensitic stainless steels, and precipitation-hardening stainless steels. The mechanism of corrosion protection for stainless steels is reviewed. The article examines the effects of composition, processing, design, fabrication, and external treatments on the corrosion of stainless steels. Various forms of corrosion, namely, general, galvanic, pitting, crevice, intergranular, stress-corrosion cracking, erosion-corrosion, and oxidation, are reviewed. Corrosion testing for; corrosion in atmosphere, water, and chemical environments; and the applications of stainless steels in various industries are also discussed.

This article discusses the five basic matrix structures in cast irons: ferrite, pearlite, bainite, martensite, and austenite. The alloying elements, used to enhance the corrosion resistance of cast irons, including silicon, nickel, chromium, copper, molybdenum, vanadium, and titanium, are reviewed. The article provides information on classes of the cast irons based on corrosion resistance. It describes the various forms of corrosion in cast irons, including graphitic corrosion, fretting corrosion, pitting and crevice corrosion, intergranular attack, erosion-corrosion, microbiologically induced corrosion, and stress-corrosion cracking. The cast irons suitable for the common corrosive environments are also discussed. The article reviews the coatings used on cast irons to enhance corrosion resistance, such as metallic, organic, conversion, and enamel coatings. It explains the basic parameters to be considered before selecting the cast irons for corrosion services.

This article focuses on the various forms of corrosion that occur in the passive range of aluminum and its alloys. It discusses pitting corrosion, galvanic corrosion, deposition corrosion, intergranular corrosion, stress-corrosion cracking, exfoliation corrosion, corrosion fatigue, erosion-corrosion, atmospheric corrosion, filiform corrosion, and corrosion in water and soils. The article describes the effects of composition, microstructure, stress-intensity factor, and nonmetallic building materials on the corrosion behavior of aluminum and its alloys. It also provides information on the corrosion resistance of anodized aluminum in contact with foods, pharmaceuticals, and chemicals.

Titanium alloys are often used in highly corrosive environments because they are better suited than most other materials. The excellent corrosion resistance is the result of naturally occurring surface oxide films that are stable, uniform, and adherent. This article offers explanations and insights on the most common forms of corrosion observed with titanium alloys, including general corrosion, crevice corrosion, anodic pitting, hydrogen damage, stress-corrosion cracking, galvanic corrosion, corrosion fatigue, and erosion-corrosion. It also provides practical strategies for expanding the useful application range for titanium and includes a comprehensive overview of available corrosion data.

This article provides a description of the classification, industrial applications, microstructures, physical, chemical, corrosion, and mechanical properties of zirconium and its alloys. It discusses the formation of oxide films and the effects of water, temperature, and pH on zirconium. The delayed hydride cracking of zirconium is also described. The article provides information on the resistance of zirconium to various types of corrosion, including pitting corrosion, crevice corrosion, intergranular corrosion, galvanic corrosion, microbiologically induced corrosion, erosion-corrosion, and fretting corrosion. The article explains the effects of tin content in zirconium and effects of fabrication on corrosion. Corrosion control measures for all types of corrosion are also highlighted. The article concludes with information on the safety precautions associated with handling of zirconium.

This article discusses corrosion fatigue, its effects on the damage tolerance of aircraft, and its predictive modeling. A conceptual framework is presented that incorporates two distinctive cyclic-based life-prediction philosophies and expands them both to include the time domain in order to consider the effects of corrosion. These philosophies include crack initiation used for safe-life design and crack growth used for damage tolerance. The article presents the methodology for computing the effects of real-time age degradation on an aircraft structure for two different corrosion types: crevice and pitting corrosion. It describes the rationale and techniques needed to apply the age-based structural integrity processes to in-service structures in order to realize the benefits throughout the full structural life cycle.