Monel properties

Nickel—Copper. In the soHd state, nickel and copper form a continuous soHd solution. The nickel-rich, nickel—copper alloys are characterized by a good compromise of strength and ductihty and are resistant to corrosion and stress corrosion ia many environments, ia particular water and seawater, nonoxidizing acids, neutral and alkaline salts, and alkaUes. These alloys are weldable and are characterized by elevated and high temperature mechanical properties for certain appHcations. The copper content ia these alloys also easure improved thermal coaductivity for heat exchange. MONEL alloy 400 is a typical nickel-rich, nickel—copper alloy ia which the nickel content is ca 66 wt %. MONEL alloy K-500 is essentially alloy 400 with small additions of aluminum and titanium. Aging of alloy K-500 results in very fine y -precipitates and increased strength (see also Copper alloys). 

As you can see from the tables in Chapter 1, few metals are used in their pure state -they nearly always have other elements added to them which turn them into alloys and give them better mechanical properties. The alloying elements will always dissolve in the basic metal to form solid solutions, although the solubility can vary between <0.01% and 100% depending on the combinations of elements we choose. As examples, the iron in a carbon steel can only dissolve 0.007% carbon at room temperature the copper in brass can dissolve more than 30% zinc and the copper-nickel system - the basis of the monels and the cupronickels - has complete solid solubility. 

The Cs structure and dimensions (Fig. 17.26b) were established by microwave spectroscopy which also yielded a value for the molecular dipole moment p. 1.72D. Other physical properties of this colourless gas are mp -115° (or -123°), bp -6°, A//f(g,298K) —34 10kJmol [or — 273kJmol when corrected for A//f(HF, g) ]. FCIO2 is thermally stable at room temperature in dry passivated metal containers and quartz. Thermal decomposition of the gas (first-order kinetics) only becomes measurable above 300° in quartz and above 200° in Monel metal ... 

Nonmagnetic drill collars are manufactured from various alloys, although the most common are Monel K500 (approximately 68% nickel, 28% copper with some iron and manganese, and 316L austenitic stainless steel). A stainless steel with the composition of 0.06% carbon, 0.50% silicon, 17-19% manganese, less than 3.50% nickel, 12% chromium, and 1.15% molybdenum, with mechanical properties of 110 to 115 Ksi tensile strength is also used. 

Monel, the classic nickel-copper alloy with the metals in the ratio 2 1, is probably, after the stainless steels, the most commonly used alloy for chemical plant. It is easily worked and has good mechanical properties up to 500°C. It is more expensive than stainless steel but is not susceptible to stress-corrosion cracking in chloride solutions. Monel has good resistance to dilute mineral acids and can be used in reducing conditions, where the stainless steels would be unsuitable. It may be used for equipment handling, alkalies, organic acids and salts, and sea water. 

Cryogenic service is usually defined as temperatures below -100°C (-150°F). Properties of some cryogenic fluids are listed in Table 2.73. Valve materials for operation at temperatures down to -268°C (-450°F) include copper, brass, bronze, aluminum, 300-series stainless steel alloys, nickel, Monel, Durimet, and Hastelloy. The limitation on the various steels falls between 0° and -150°F (-17 and -101°C), with cast carbon steel representing 0°F (-17°C) and 3.5% nickel steel being applicable to -150°F (-101°C). Iron should not be used below 0°F (-17°C). 

Monel, an alloy of nickel containing 67 percent nickel and 30 percent copper, is often used in the food industries. This alloy is stronger than nickel and has better corrosion-resistance properties than either copper or nickel. Another important nickel alloy is Inconel (77 percent nickel and 15 percent chromium). The presence of chromium in this alloy increases its resistance to oxidizing conditions. 

Hydrofluoric acid is the most basic common precursor of most fluorochemicals. Aqueous hydrofluoric acid is prepared by reaction of sulfuric acid with fluorspar (CaF2). Because HF etches glass with formation of silicon tetrafluoride, it must be handled in platinum, lead, copper. Monel (a Cu-Ni alloy developed during the Manhattan Project), or plastic (e.g. polyethylene or PTFE) apparatus. The azeotrope contains 38 % w/w HF and it is a relatively weak acid (pfC 3.18, 8 % dissociation), comparable with formic acid. Other physicochemical properties of hydrofluoric acid are listed in Table 1.2. 

Not much is known about astatine because it is very rare, is radioactive, and decays very quickly. Would you predict the chemical and physical properties of astatine to be more like those of a metal or nonmetal Defend your answer on the basis of astatine s location on the periodic table. Elemental chlorine is obtained by the electrolysis of molten NaCl (Downs cell). Elemental fluorine is obtained by the electrolysis of KHE2 in a cell made of Monel metal (a stainless steel alloy). Both of these processes are dangerous. Why ... 

Metals used for liquid hydrogen equipment must have satisfactory properties at very low operating temperatures. Ordinary carbon steels lose their ductility at liquid hydrogen temperatures and are considered too brittle for this service. Suitable materials include austenitic chromium-nickel steels (stainless steels), copper, copper silicon alloys, aluminum. Monel, and some brasses and bronzes. 

Bromine trifluoride is a pale yellow hquid at 298 K and is an aprotic non-aqueous solvent. Selected physical properties are given in Table 9.8 and the compound is discussed further in Section 17.7. Bromine trifluoride is an extremely powerful fluorinating agent and fluorinates essentially every species that dissolves in it. However, massive quartz is kine-tically stable towards Brp3 and the solvent can be handled in quartz vessels. Apparatus made from Cu, Ni or Monel metal (68% Ni and 32% Cu) can also be used the metal surface becomes protected by a thin layer of metal fluoride. 

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