Search Results for chromium

This article discusses the general welding characteristics and metallurgical welding considerations that play an important function during the welding of nickel, nickel-copper, nickel-chromium, and nickel-chromium-iron alloys.

This article is a compilation of binary alloy phase diagrams for which chromium (Cr) is the first named element in the binary pair. The diagrams are presented with element compositions in weight percent. The atomic percent compositions are given in a secondary scale. For each binary system, a table of crystallographic data is provided that includes the composition, Pearson symbol, space group, and prototype for each phase.

This article is a compilation of ternary alloy phase diagrams for which chromium (Cr) is the first-named element in the ternary system. The other elements are Fe, Mn, Mo, N, Nb, Ni, Ti, V and W. The diagrams are presented with element compositions in weight percent. The article includes 55 phase diagrams (liquidus projection, solidus projection, isothermal section and vertical section).

This article focuses on various heat-treating practices, namely, normalizing, annealing, stress relieving, preheating, austenitizing, quenching, tempering, and nitriding for cold-work tool steels. The cold-work tool steels include medium-alloy air-hardening tool steels, high-carbon high-chromium tool steels, and high-vanadium-powder metallurgy tool steels. The article also describes the properties, types, nominal compositions and designations of these cold-work tool steels.

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.

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 focuses on alternatives to chromium in both hard chromium plating and chromate conversion coating. These include electroless nickel plating, nickel-tungsten composite electroplating, spray coating applications, and cobalt/molybdenum-base conversion coating. The article discusses the material and process substitutions that can be used to eliminate the use or emissions of chromium in industrial processes. It describes the physical characteristics of each coating, economics, environmental impacts, advantages, and disadvantages of alternative processes.

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.

Hard chromium plating is produced by electrodeposition from a solution containing chromic acid and a catalytic anion in proper proportion. This article presents the major uses of hard chromium plating, and focuses on the selection factors, plating solutions, solution and process control, equipment, surface preparation, and crack patterns and other characteristics of hard chromium plating. It offers recommendations for the design and use of plating racks, describes the problems encountered in hard chromium plating, and their corrective procedures. The article provides information on the removal of chromium plate from coated metals, recovery and disposal of wastes, and stopoff media for selective plating.

This article discusses some of the additive manufacturing (AM) based fabrication of alloys and their respective mechanical, electrochemical, and in vivo performance. Firstly, it briefly discusses the three AM techniques that are most commonly used in the fabrication of metallic biomedical-based devices: binder jetting, powder-bed fusion, and directed-energy deposition. The article then characterizes the electrochemical properties of additive-manufactured/processed cobalt-chromium alloys. This is followed by sections providing an evaluation of the biological response to CoCr alloys in terms of the material and 3D printing fabrication. Discussion on the biological response as a function of direct cellular activity on the surface of CoCr alloys in static conditions (in vitro), in dynamic physiological conditions (in vivo), and in computer-simulated conditions (in silico) are further discussed in detail. Finally, the article provides information on the qualification and certification of AM-processed medical devices.