Search Results for substrate potential

This article begins with a list of the factors that influence the properties of physical vapor deposited films. It describes the steps involved in ion plating, namely, surface preparation, nucleation, interface formation, and film growth. The article discusses the factors influencing the properties of ion-plated films. The sources of potential applied on substrate surface, bombarding species, and depositing species are addressed. The article also provides information on the parameters that influence bombardment. It concludes with a discussion on the advantages, limitations, and applications of ion plating.

This article focuses on the testing and typical corrosion behavior of coating-substrate systems in aqueous solutions and humid aggressive atmospheres. It includes a short review of the fundamentals of corrosion, followed by a discussion of specific system behavior, electrochemical and laboratory accelerated tests, and simulated service tests. The article also contains examples of different types of corrosion damage and presents guidelines for improving corrosion resistance.

This article discusses the properties of aluminum surface and the applications of aluminum alloys. It explains the effects of trace elements on aluminum alloys. The article considers microstructural development of aluminum in terms of the surface and explains how it will impact corrosion resistance and surface treatment. It describes the thermodynamics of equilibrium oxidation processes and non-equilibrium corrosion processes. The article provides a discussion on aluminum oxidation under atmospheric and dynamic conditions. It presents the potential/pH (Pourbaix) diagram for aluminum under atmospheric and dynamic conditions. The article also explains the polarization effects during the formation of stable aluminum oxide under dynamic conditions. It concludes with information on the designation system for aluminum finishes.

This article discusses the factors affecting corrosion behavior. It describes galvanic corrosion and its protection methods. The article also provides information on coatings and inhibitors, which are used in corrosion protection.

Surface modification is the alteration of the surface composition or structure using energy or particle beams. This article discusses two different surface modification methods. The first, ion implantation, is the introduction of ionized species into the substrate using kilovolt to megavolt ion accelerating potentials. The second method, laser processing, is high-power laser melting with or without mixing of materials precoated on the substrate, followed by rapid melt quenching. The article also describes the advantages and disadvantages of the surface modification approach to promote corrosion resistance.

Anodizing produces a uniform, continuous, highly ordered network of individual cells comprising a layer whose thickness and cell dimensions, and ultimately engineering properties, depend on the electrochemical parameters of the anodizing process. This article discusses the nucleation and growth of anodic aluminum oxide and the important characteristics of the finished porous anodic aluminum oxide. In industry, anodic oxides and the anodizing processes have been categorized into types that exhibit specific properties to suit specific applications. The article reviews the two most basic types of oxides, namely, barrier-layer anodic oxides and porous anodic oxides. It concludes with a description of postanodizing processes, such as dyeing and sealing.

Thermal spray processes involve complete or partial melting of a feedstock material in a high-temperature flame, and propelling and depositing the material as a coating on a substrate. This article describes the properties of sprayed electronic materials, including dielectrics, conductors, and resistors, and discusses their implications and associated limitations for device applications and potential remedial measures. The article presents specific examples of electrical/electronic device applications, including electromagnetic interference/radio-frequency interference shielding, planar microwave devices, waveguide devices, sensing devices, solid oxide fuel cells, heating elements, electrodes for capacitors and other electrochemical devices.

The friction surfacing process enables deposition of a wide variety of high-specification materials with an ideal metallurgical bond onto a range of metal substrates. This article provides a process description and discusses the equipment used for, and the applications of, friction surfacing.

The nitriding process typically involves the introduction of nitrogen into the surface-adjacent zone of a component, usually at a temperature between 500 and 580 deg C. This article provides an overview of the essential aspects of the thermodynamics and kinetics of nitriding and nitrocarburizing of iron-base materials with gaseous processes. It describes nitriding potentials and the Lehrer diagram, carburizing potentials, controlled nitriding and nitrocarburizing, and the microstructural evolution of the compound layer and the diffusion zone.

This article discusses the various factors that affect the corrosion performance of electroplated coatings. It describes the effects of environment and the deposition process on substrate coatings. The article provides a discussion on the electrochemical techniques capable of predicting the corrosion performance of a plated part. It reviews the designs of coating systems for optimal protection of the substrate. The article also discusses controlled weathering tests and accelerated tests used to predict and determine the relative durability of the coating.

In the friction surfacing process, a rotating consumable is brought into contact with a moving substrate, which results in a deposited layer on the substrate. This article describes the process as well as the equipment used. It also provides information on the applications of the friction surface process.

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.

Wipe solvents are used to remove contaminants from a workpiece before it undergoes manufacturing operations that require clean surfaces, such as bonding, sealing, painting, welding, plating, specialized surface treatment procedures, and others. This article describes the evaluation parameters for wipe solvent cleaners, including methyl ethyl ketone, methyl isobutyl ketone, trichloroethene, tetrachloroethylene, acetone, toluene, dichloromethane, benzene, xylene, and other alternate wipe solvent cleaners. It contains a table that lists the compositions and properties of wipe solvent cleaners.

Sputtering is a nonthermal vaporization process in which the surface atoms are physically ejected from a surface by momentum transfer from an energetic bombarding species of atomic/molecular size. It uses a glow discharge or an ion beam to generate a flux of ions incident on the target surface. This article provides an overview of the advantages and limitations of sputter deposition. It focuses on the most common sputtering techniques, namely, diode sputtering, radio-frequency sputtering, triode sputtering, magnetron sputtering, and unbalanced magnetron sputtering. The article discusses the fundamentals of plasma formation and the interactions on the target surface. A comparison of reactive and nonreactive sputtering is also provided. The article concludes with a discussion on the several methods of process control and the applications of sputtered films.

This article provides a general technical description of thermal spray coatings used for corrosion protection in atmospheric and aqueous environments. It further discusses two basic coating approaches of corrosion protection, namely, the sacrificial coating of thermal spray aluminum (TSA) and thermal spray zinc (TSZ), and the barrier-type coating of corrosion-resistant materials. The emphasis is on sacrificial coatings. The article describes the steps involved in the application of TSA and TSZ: surface preparation, coating deposition, and postspray treatment. It discusses their field exposure tests and application history. The article also contains helpful information on the dense barrier coatings by high-velocity spraying processes along with their corrosion performance.

This article is a brief account of low-energy ion-scattering spectroscopy (LEIS) for determining the atomic structure of solid surfaces. It begins with a description of the general principles of LEIS. This is followed by a section providing information on the equipment used for LEIS. Various steps involved in the sample preparation, calibration, and data analysis are then discussed. The article concludes with a section on the applications and interpretation of LEIS in material analysis, including discussion on surface structural analysis, layer-by-layer (Frank-van der Merwe) growth, and low-energy atom-scattering spectroscopy.

Multiple-layer alloy electrodeposition involves the formation of an inhomogeneous alloy consisting of lamellae of different composition. This article reviews the process description, engineering parameters, characterization, and applications of multiple-layer alloys. Pulsed-current plating and pulsed-potential plating are also discussed.