Search Results for microdiscontinuous coating

Most decorative chromium coatings have been applied using hexavalent and trivalent plating processes that are based on chromic anhydride. This article provides a discussion on chromium electrodeposits and their use as microdiscontinuous coating for corrosion protection. It focuses on the operating conditions of various chromium plating parameters: bath composition, temperature, voltage, anode materials, and current density. These parameters need to be considered for obtaining high quality decorative chromium coatings. An overview of plating problems encountered in chromium plating and their corrections is also provided.

This article discusses the process considerations and deposit properties of nickel plating. It describes the Watts solution and the anode materials used. The article focuses on the nickel plating processes used for decorative, engineering, and electroforming purposes. It provides information on the quality control of nickel plating. It concludes with a review of the environmental, health, and safety considerations associated with nickel plating.

Chromium alloys yield alloy coatings with properties that range from completely satisfactory to marginally acceptable, depending on the end use. This article provides a detailed description of plating solutions and deposition conditions and rates of chromium-iron, chromium-nickel, and chromium-iron-nickel alloys.

This article discusses the corrosion of chromium electrodeposits and the ways for optimizing corrosion resistance. It describes the processing steps and conditions for hard chromium plating. These steps include pretreatment, electroplating, and posttreatment. The article also provides information on duplex coatings and the applications of chromium electrodeposits.

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.

This article discusses the classifications, compositions, properties, advantages, disadvantages, limitations, and applications of the most commonly used methods for surface engineering of carbon and alloy steels. These include cleaning methods, finishing methods, conversion coatings, hot-dip coating processes, electrogalvanizing, electroplating, metal cladding, organic coatings, zinc-rich coatings, porcelain enameling, thermal spraying, hardfacing, vapor-deposited coatings, surface modification, and surface hardening via heat treatment.

Copper can be electrodeposited from numerous electrolytes. Cyanide and pyrophosphate alkalines, along with sulfate and fluoborate acid baths, are the primary electrolytes used in copper plating. This article provides information on the chemical composition, plating baths, and operating conditions of electrodeposition processes for chromium plating, nickel plating, iron plating, cadmium plating, zinc plating, indium plating, lead plating, tin plating, silver plating, gold plating, brass plating, bronze plating, tin-lead plating, zinc-iron plating, and zinc-nickel plating. The article also discusses selective plating, electroforming, and other processes and where they are typically used.

Fracture toughness is the ability of a material to withstand fracture in the presence of cracks. This article focuses on the use of fracture toughness as a parameter for engineering and design purposes. Both linear elastic and elastic-plastic fracture mechanics concepts are reviewed as they relate to fracture toughness and design process. The article explores the use of plane strain fracture toughness, crack-tip opening displacement, and the J-integral as the criteria for the design and safe operation of structures and mechanical components. It discusses the variables affecting fracture toughness, including yield strength, loading rate, temperature, and material thickness. A summary of different fatigue and fracture mechanics design philosophies and their relationship with fracture toughness is provided. The article concludes with information on the examples of fracture toughness in design.

Fatigue crack initiation is an important aspect of materials performance in design. This article summarizes some fundamental concepts and procedures for the fatigue life prediction of relatively homogeneous, wrought metals when a major portion of total life is exhausted in crack initiation. It presents an overview of the strain-based, as opposed to stress-based, criterion of material behavior and fatigue analysis. The article describes the cyclic stress-strain behavior of metals to illustrate the inadequacy of the monotonic or tensile stress-strain curve in accounting for material instabilities caused by cyclic deformations. It discusses the effect of mean stress on fatigue life and presents the analysis of cumulative fatigue damage. The article concludes with examples of application techniques for fatigue life prediction.

Of the various thermal processing methods for steel, heat treating has the greatest overall impact on control of residual stress and on dimensional control. This article provides an overview of the effects of material- and process-related parameters on the various types of failures observed during and after heat treating of quenched and tempered steels. It describes phase transformations of steels during heating, cooling of steel with and without metallurgical transformation, and the formation of high-temperature transformation products on the surface of a carburized part. The article illustrates the use of carbon restoration on decarburized spring steels. Different geometric models for carbide formation are shown schematically. The article also describes the different microstructural features such as grain size, microcracks, microsegregation, and banding.