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 describes mechanical/electrochemical phenomena related to in vivo degradation of metals used for biomedical applications. It discusses the properties and failure of these materials as they relate to stress-corrosion cracking (SCC) and corrosion fatigue (CF). The article presents the factors related to the use of surgical implants and their deterioration in the body environment, including biomedical aspects, chemical environment, and electrochemical fundamentals needed for characterizing CF and SCC. It provides a discussion on the use of metallic biomaterials in surgical implant applications, such as orthopedic, cardiovascular surgery, and dentistry. It addresses key issues related to the simulation of an in vivo environment, service conditions, and data interpretation. These include the frequency of dynamic loading, electrolyte chemistry, applicable loading modes, cracking mode superposition, and surface area effects. The article explains the fundamentals of CF and SCC, and presents the test findings from laboratory, in vivo, and retrieval studies.

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.

This article provides information on biomedical aspects such as active biological responses and the chemical environment characterizing the internal physiological milieu, as well as electrochemical fundamentals needed for characterizing corrosion fatigue (CF) and stress-corrosion cracking (SCC). It discusses some of the mechanical and electrochemical phenomena related to the in vivo degradation of materials used for biomedical applications. These materials include stainless steels, cobalt and titanium-base alloy systems, and dental amalgam. The article addresses key issues related to the simulation of the in vivo environment, service conditions, and data interpretation. The factors influencing susceptibility to CF and SCC are reviewed. The article describes the testing methodology of CF and SCC. It also summarizes findings from laboratory testing, in vivo testing and retrieval studies related to CF and SCC.

This article tabulates the chemical composition of iron-base, titanium-base, and cobalt-base alloys and illustrates the microstructures of these materials. It discusses the surface morphology and chemistry of oxide-film-covered alloys and provides insights into the interaction. The article illustrates the interfacial structure of a biomaterial surface contacting with the biological environment. It describes the corrosion behavior of stainless steel, cobalt-base alloy, and titanium alloys. The electrochemical methods used for studying metallic biomaterials corrosion are also discussed. The article concludes with information on the biological consequences of in vivo corrosion and biocompatibility.

Biomaterials are the man-made metallic, ceramic, and polymeric materials used for intracorporeal applications in the human body. This article primarily focuses on metallic materials. It provides information on basic metallurgy, biocompatibility, chemistry, and the orthopedic and dental applications of metallic biomaterials. A table compares the mechanical properties of some common implant materials with those of bone. The article also provides information on coatings, ceramics, polymers, composites, cements, and adhesives, especially where they interact with metallic materials.

This article discusses the mechanisms of metal and alloy biocompatibility. It provides information on early testing and experience with metals in medical device applications. The article describes the response of implant and particulate materials to severe corrosion. It provides a description of metal binding and its effects on metabolic processes. Hypersensitive responses to metal ions are also reviewed. The article concludes with a discussion on the possible cancer-causing effects of metallic biomaterials.

In the field of medical device development and testing, the corrosion of metallic parts can lead to significant adverse effects on the biocompatibility of the device. This article describes the mechanisms of metal and alloy biocompatibility. It reviews the response of implant metals and particulate materials to corrosion. The effect of metal ions from an implanted device on the human body is also discussed. The article concludes with information on the possible cancer-causing effects of metallic biomaterials.

This article focuses on the use of noble and precious metals for biomedical applications. These include gold, platinum, palladium, ruthenium, rhodium, iridium, and osmium. The physical and mechanical properties of noble and precious metals are presented in tables. A brief discussion on the ancient history of noble and precious metal use in dentistry is provided. The article discusses the use of direct gold dental filling materials, direct silver dental filling materials, traditional amalgam alloys, high-copper amalgam alloys, and gallium alloys in biomedical applications. It also provides information on gold coatings and iridium oxide coatings for stents.

The biocompatibility of a material relates to its immunological response, toxicity profile, and ability to integrate with surrounding tissue without undesirable local or systemic effects on a patient. This article underscores the transformation of the medical device design ecosystem engaged as an integral part of the device ecosystem. It discusses the applications of biomaterials, including orthopedic, cardiovascular, ophthalmic, and dental applications. The article describes four major categories of biomaterials such as metals, polymers, glass and ceramics, and composites. A discussion on natural materials, nanomaterials, and stem cells is also provided. The article concludes with examples of biomaterials applications, such as endovascular devices, knee implants, and neurostimulation.

Titanium and its alloys have been used extensively in a wide variety of implant applications, such as artificial heart pumps, pacemaker cases, heart valve parts, and load-bearing bone or hip joint replacements or bone splints. This article discusses the properties of titanium and its alloys and presents a list of titanium-base biomaterials. Titanium components are produced in wrought, cast, and powder metallurgy (PM) form. The article describes forging, casting, and heat treating of titanium alloys for producing titanium components. Typical mechanical properties of titanium biomedical implant alloys are listed in a tabular form. The article presents an overview of the surface-modification methods for titanium and its alloys implants. It concludes with a section on biocompatibility and in vivo corrosion of titanium alloys.

Porous coatings are used in the field of joint replacement, particularly in cementless total hip/knee arthroplasty. This article reviews the offerings and biomaterial properties in orthopedic surgery for the contemporary class of highly porous metals. It describes the traditional porous metals/coatings having an open-cell structure, high porosity, and a microstructure resembling that of the cancellous bone. The traditional porous metal/coating includes fiber-metal mesh, cobalt-chromium (CoCr) beads, cancellous-structured titanium, and plasma spray. The article discusses other porous metals/coatings that have been developed due to the limitations of traditional porous metals for numerous open-cell-structured metals, such as titanium-base foams and trabecular metals.

This article outlines the selection criteria for choosing an implant material for biomedical devices in orthopedic, dental, soft-tissue, and cardiovascular applications. It details the development of various implants, such as metallic, ceramic, and polymeric implants. The article discusses specific problems associated with implant manufacturing processes and the consequent compromises in the properties of functionally graded implants. It describes the manufacturing of the functionally-graded hip implant by using the LENS process. The article reviews four different types of tissue responses to the biomaterial. It discusses the testing methods of implant failure, such as in vitro and in vivo assessment of tissue compatibility.

This article provides an overview of the fundamentals of tribology. It describes the advantages, disadvantages, and applications of the pin-on-disk method, which is the most commonly used configuration for testing biomaterials and for the reproducible measurement of friction and wear. The article illustrates a practical tribocorrosion setup that allows a user to perform wear tests in corrosive environments under well-defined electrochemical conditions and at controlled temperature. It explains the effect of changes in electrical contact resistance on tribological mode. The article discusses various in vivo environmental conditions in tribological tests. Some typical examples of biomaterials testing are also provided.

This article reviews the concepts considered important for an understanding of the processes used for preparing cobalt-chromium alloy implants, the microstructures resulting from this processing, and the resulting material properties. The review includes solidification of alloys, diffusionless (martensitic) phase transformation as occurs with face-centered cubic to hexagonal close-packed transformation in cobalt-chromium alloys, and stacking faults and twins and their role in this transformation. It also discusses the strengthening mechanisms that are responsible for the mechanical properties of cast and wrought cobalt alloys. The article contains tables that list the commonly used cobalt alloys and their biomedical applications and chemical compositions. It discusses the mechanical and corrosion properties of cobalt alloys, and provides a description of the microstructure of cobalt alloys.

This article includes a collection of color images that aid in the identification and classification of forms of corrosion in industries and environments. It emphasizes the negative aspects of corrosion and examines the cost and the effort to test, evaluate, simulate, and prevent corrosion. The ability of corrosion to undo the best complex engineered systems has been documented.

This article is an overview of the division Surface Analysis of this volume. The division covers various developed surface-analysis techniques, such as scanning probe and atomic force microscopy. The division focuses on the analysis of surface layers that are less than 100 nm. A quick reference summary of surface-analysis methods is presented in this article.