Copper niobium alloy

Many of uses of tin are also those of lead, because the metals form useful alloys. When lead is alloyed with a few percent of tin, it becomes harder and more durable. Although other compositions are produced, common solder consists of about an equal mixture of tin and lead. An alloy known as type metal contains about 82% Pb, 15% Sb, and 3% Sn, and pewter contains approximately 90% tin that is alloyed with copper and antimony. Babbitt, an alloy used in making bearings, contains 90% Sn, 7% Sb, and 3% Cu. Tin is also used to coat other metal objects to retard corrosion, and a tin-niobium alloy is used in superconducting magnets. 

Other interesting matrices are niobium alloys (investigated for long-term, high-temperature applications in space power systems) and copper and silver for electrical applications and heat exchangers [6.50,6.51]. 

Elements, which usually originate from alloyed steel scrap and non-ferrous metals in the steel charge, of the type which can be added to steels as alloying elements. They include nickel, chromium, molybdenum, copper, niobium and vanadium. Residual elements... 

COPPER/NIOBIUM ELEMENTS CLAD WITH PURE TIN OR COPPER-TIN ALLOY... 

Besides nickel, cobalt, and copper-based alloys, there are other industrial non-ferrous corrosion-resistant metals such as the reactive metals zirconium, titanium, niobium, and tantalum. Table 2-18 shows the chemical composition and UNS designations of the reactive metals alloys. 

Characteristic transformation temperatures depend strongly on composition (see table on next page and the previous section on chemistry). Typical hysteresis widths range from 10 C (18 °F) for certain titanium-nickel-copper alloys, to 40 to 60 °C (72 to 108 °F) for binary alloys, to 100 °C (180 °F) for titanium-nickel-niobium alloys. 

Antonova et al. (33) discuss different fluxing agents in combination with combustion in a tube furnace at 1250 to 1300°C in an oxygen stream of 200 ml/min. Carbon dioxide is determined by titrimetry. For niobium alloys they propose copper as fluxing agent, for molybdenum alloys a mixture of zinc oxide and copper, and for tungsten alloys copper oxide. 

Since the number of slip systems is not usually a function of temperature, the ductility of face-centered cubic metals is relatively insensitive to a decrease in temperature. Metals of other crystal lattice types tend to become brittle at low temperatures. Crystal structure and ductility are related because the face-centered cubic lattice has more slip systems than the other crystal structures. In addition, the slip planes of body-centered cubic and hexagonal close-packed crystals tend to change at low temperature, which is not the case for face-centered cubic metals. Therefore, copper, nickel, all of the copper-nickel alloys, aluminum and its alloys, and the austenitic stainless steels that contain more than approximately 7% nickel, all face-centered cubic, remain ductile down to the low temperatures, if they are ductile at room temperature. Iron, carbon and low-alloy steels, molybdenum, and niobium, all body-centered cubic, become brittle at low temperatures. The hexagonal close-packed metals occupy an intermediate place between fee and bcc behavior. Zinc undergoes a transition to brittle behavior in tension, zirconium and pure titanium remain ductile. 

The important (3-stabilizing alloying elements are the bcc elements vanadium, molybdenum, tantalum, and niobium of the P-isomorphous type and manganese, iron, chromium, cobalt, nickel, copper, and siUcon of the P-eutectoid type. The P eutectoid elements, arranged in order of increasing tendency to form compounds, are shown in Table 7. The elements copper, siUcon, nickel, and cobalt are termed active eutectoid formers because of a rapid decomposition of P to a and a compound. The other elements in Table 7 are sluggish in their eutectoid reactions and thus it is possible to avoid compound formation by careful control of heat treatment and composition. The relative P-stabilizing effects of these elements can be expressed in the form of a molybdenum equivalency. Mo (29) ... 

Stainless Steel There are more than 70 standard types of stainless steel and many special alloys. These steels are produced in the wrought form (AISI types) and as cast alloys [Alloy Casting Institute (ACI) types]. Gener y, all are iron-based, with 12 to 30 percent chromium, 0 to 22 percent nickel, and minor amounts of carbon, niobium (columbium), copper, molybdenum, selenium, tantalum, and titanium. These alloys are veiy popular in the process industries. They are heat- and corrosion-resistant, noncontaminating, and easily fabricated into complex shapes. 

The basic corrosion behaviour of stainless steels is dependent upon the type and quantity of alloying. Chromium is the universally present element but nickel, molybdenum, copper, nitrogen, vanadium, tungsten, titanium and niobium are also used for a variety of reasons. However, all elements can affect metallurgy, and thus mechanical and physical properties, so sometimes desirable corrosion resisting aspects may involve acceptance of less than ideal mechanical properties and vice versa. 

Other more highly alloyed types, of which a typical example is given in Table 3.11, have the designation of precipitation hardening martensitic. Relative to the simple 13% chromium types they have a substantial nickel content and low carbon with additions from molybdenum, copper, aluminium, titanium and niobium. These offer improved corrosion resistance, strength, toughness, weldability and fabrication properties, but not always together. 

The corrosion behaviour of amorphous alloys has received particular attention since the extraordinarily high corrosion resistance of amorphous iron-chromium-metalloid alloys was reported. The majority of amorphous ferrous alloys contain large amounts of metalloids. The corrosion rate of amorphous iron-metalloid alloys decreases with the addition of most second metallic elements such as titanium, zirconium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, cobalt, nickel, copper, ruthenium, rhodium, palladium, iridium and platinum . The addition of chromium is particularly effective. For instance amorphous Fe-8Cr-13P-7C alloy passivates spontaneously even in 2 N HCl at ambient temperature ". (The number denoting the concentration of an alloy element in the amorphous alloy formulae is the atomic percent unless otherwise stated.)... 

The question of the compatibility of metals and alloys with carbon and carbonaceous gases has assumed considerable importance in connection with the development of the gas-cooled nuclear reactor in which graphite is used as a moderator and a constituent of the fuel element, and carbon dioxide as the coolant. Tests of up to 1 000 h on a series of metals and nickel-containing alloys under pressure contact with graphite at 1 010°C" showed that only copper was more resistant than nickel to diffusion of carbon and that the high-nickel alloys were superior to those of lower nickel content. The more complex nickel-chromium alloys containing titanium, niobium and aluminium were better than the basic nickel-chromium materials. 

Some positive steps were made in this direction through the use of niobium-based alloys. In 1973 the alloy Nb3Ge was found to have a Tc = 23 K, which remained the highest attainable critical temperature until 1986. In 1986 two IBM scientists in Zurich, the German, Johannes Georg Bednorz and the Swiss, Karl Alex Muller found that a ceramic oxide based on lanthanum, barium and copper (of stoichiometry... 

There are transition metals in many of the products that people use in daily life. Some of these metals have obvious roles, such as the coin metals of gold, silver, and copper. Iron, which makes up 90% of all metal that is refined, or purified for use, is found in everything from tools to paper staples to washing machines. The most important iron product is steel, an iron-based metal alloy. Most steel made for manufacturing purposes is iron alloyed with the element carbon, which makes the steel much harder than iron alone. Several other transition metals are alloyed with iron to make different kinds of steel for different uses. Vanadium, niobium, molybdenum, manganese, chromium, and nickel are all used in steel alloys. For instance, chromium and nickel are alloyed with iron to create stainless steel, a type of steel that does not rust and is used in surgical instruments, cookware, and tools. Some famous landmarks such as the top of the Chrysler skyscraper in New York City and the St. Louis Gateway Arch are covered in stainless steel. 

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