Search Results for rhenium powders

Refractory metals are extracted from ore concentrates or scrap, processed into intermediate chemicals, and then reduced to metal, usually in powder form. This article discusses the raw materials needed and the processing steps for producing pure and alloyed refractory metal powders. The effects of processing conditions on the physical and chemical properties of tungsten, molybdenum, tantalum, niobium, and rhenium powders are reviewed.

This article discusses the pressing and sintering of various refractory metal powders for the production of intermediate products as well as special cases of finished products. The metal powders considered include tungsten, molybdenum, tantalum, niobium and their alloys, as well as rhenium.

This article focuses on the selection, properties, and applications of powder metallurgy refractory metals and their alloys, including tungsten, molybdenum, tantalum, niobium, and rhenium.

This article describes various procedures used in the metallographic preparation of niobium, tantalum, molybdenum, and tungsten alloys. It provides information on sectioning, grinding, mounting, polishing, and electrolytic etching as well as alternate procedures that have been used on refractory metals. The article presents and analyzes several micrographs, provides etchant formulas for various materials, and discusses the unique characteristics of rhenium and its alloys.

The refractory metals include niobium, tantalum, molybdenum, tungsten, and rhenium. They are readily degraded by oxidizing environments at moderately low temperatures. Protective coating systems have been developed, mostly for niobium alloys, to permit their use in high-temperature oxidizing aerospace applications. This article discusses the properties, processing, applications, and classes of refractory metals and its alloys, namely molybdenum, tungsten, niobium, tantalum and rhenium. It also provides an outline of the coating processes used to improve their oxidation resistance.

This article briefly discusses the annealing practices for refractory metals such as tungsten, molybdenum, niobium, tantalum, and rhenium and their alloys. It also presents the applications and properties of these metals and their alloys.

All refractory metals, except osmium and iridium, have the highest melting temperatures and lowest vapor pressures of all metals. This article discusses the commercial applications, and production procedures of refractory metals and alloys. These procedures include fabrication, machining, forming, cleaning, joining, and coatings. The article also presents information on, and specifications for, the following metals and their alloys: niobium, tantalum, molybdenum, tungsten, rhenium, and refractory metal fiber-reinforced composites. It discusses the processes involved in their production, their mechanical properties, physical properties, thermal properties, electrical properties, chemical properties, applications, and corrosion resistance.

This article discusses special metallurgical considerations during the fusion welding of refractory metal alloys. These considerations are: microstructure, interstitial impurities, and welding conditions that are considered during the fusion welding of refractory metal alloys, including tantalum, niobium, rhenium, molybdenum, and tungsten. Refractory metal alloys are discussed in the order of decreasing weldability: tantalum, niobium, rhenium, molybdenum, and tungsten.

Refractory metals are typically processed from powders into ingots that are subsequently swaged into round bars or rolled into plates. Secondary operations are required to fabricate more complex refractory metal components. This article discusses two such secondary operations, namely, machining and joining processes for tungsten, tungsten heavy alloys, molybdenum, tantalum, niobium, and rhenium components. It describes the various types of metal joining processes, including mechanical fastening, brazing, and welding.

This article focuses on the forging characteristics of different types of refractory metals and alloys, namely, niobium and niobium alloys, molybdenum and molybdenum alloys, tantalum and tantalum alloys, and tungsten and tungsten alloys.

This article presents the principles of chemical vapor deposition (CVD) with illustrations. It discusses the types of CVD processes, namely, thermal CVD, plasma CVD, laser CVD, closed-reactor CVD, chemical vapor infiltration, and metal-organic CVD. The article reviews the CVD reactions of materials related to hard, tribological, and high-temperature coatings and to free-standing structures. It concludes by reviewing the advantages, disadvantages, and applications of CVD.

Thermocouple devices are the most widely used devices for measurement of temperature in the metals industry. Favorable characteristics of these devices include good accuracy, suitability over a wide temperature range, fast thermal response, ruggedness, high reliability, low cost, and great versatility of application. Thermocouples are grouped into two broad categories, namely, standard thermocouples, including five base-metal thermocouples and three noble-metal thermocouples that have been given letter designations, and nonstandard thermocouples, including iridium-rhodium, platinum-molybdenum, platinel, and tungsten-rhenium thermocouples. This article discusses the basic principles, classification, and properties of thermocouples, and the techniques for insulating and protecting thermocouple wires from the operating environment.

This article focuses on the principles and applications of X-ray photoelectron spectroscopy (XPS) for the analysis of elemental and chemical composition. The discussion covers the nomenclature, instruments, and specimen preparation process of XPS. Some of the factors pertinent to the calibration of materials for accurate measurements using XPS are provided, along with some aspects of the accuracy in quantitative analysis by XPS. In addition, the article presents examples of how XPS data can be used to solve problems with surface interactions.

This article provides an in-depth review of thermocouples and the metals from which they are made. It explains how dissimilar metal conductors in contact at opposite ends can generate an electromotive force if the junctions are heated or cooled to different temperatures. The article discusses thermocouple circuits and instrumentation, calibration methods, insulation requirements, operating ranges, measurement errors, and maintenance procedures. It also provides property data and emf curves for common metals and thermocouple types, and contains information on color coding used around the world.

Chemical vapor deposition (CVD) involves the formation of a coating by the reaction of the coating substance with the substrate. Serving as an introduction to CVD, the article provides information on metals, ceramics, and diamond films formed by the CVD process. It further discusses the characteristics of different pack cementation processes, including aluminizing, siliconizing, chromizing, boronizing, and multicomponent coating.

This article is a comprehensive collection of tables that list the values for hardness of plastics, rubber, elastomers, and metals. The tables also list the tensile yield strength and tensile modulus of metals and plastics at room temperature. A comparison of various engineering materials, on the basis of tensile strength, is also provided.

This article focuses on the monolithic form of nonferrous alloys, including aluminum, copper, nickel, cobalt, titanium, zinc, magnesium, and beryllium alloys. Each metal and alloy offers unique combinations of useful physical, chemical, and structural properties that are made available by its particular composition and the proper choice of processing method. The article describes the composition, designation system, properties, and processing method of these metals and alloys. It discusses the effect of alloying elements in these alloys. The article explains microstructure/property relationships that are used to make specific properties available to the designers of structural applications. It provides examples of phase diagrams that illustrate eutectic and peritectic reactions.

Metal powders are used as fuels in solid propellants, fillers in various materials, such as polymers or other binder systems, and for material substitution. They are also used in food enrichment, environmental remediation market, and magnetic, electrical, and medical application areas. This article reviews some of the diverse and emerging applications of ferrous and nonferrous powders. It also discusses the functions of copier powders and the processes used frequently for copier powder coating.