Nickel thermal properties

The thermal properties of the nickel complexes obtained with the cupferron ligand (260), NiLj, and with dicupferron (261), NiL-H20, were investigated.1916 1917... 

The metal has a hexagonal close-packed lattice and resembles other transition metals such as iron and nickel in being hard, refractory (m.p. 1680°+10°, b.p. 3260°), and a good conductor of heat and electricity. It is, however, quite light in comparison to other metals of similar mechanical and thermal properties and unusually resistant to certain kinds of corrosion and has therefore come into demand for special applications in turbine engines and industrial chemical, aircraft, and marine equipment. 

The glass-coloring experiments have been performed with gold, silver, nickel and other metals, which are much more difficult to handle theoretically than the alkalis. Among the latter, sodium is the best representative of the nearly free electron gas or jellium model which forms the basic assumption of some of the articles found here. Therefore this review is restricted to sodium clusters, and more specifically to their optical and thermal properties. 

Metals share excellent mechanical and conductivity (electrical and thermal) properties ideal for high stress apphcations such as heart valves. Titanium—nickel alloys have become the most common material for metaUic cardiovascular applications (stents and valves) due to unique properties shape memory effect, super-elasticity, high degree of biocompatibility moreover, they are almost completely inert and nonmagnetic. 

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). 

Because oxides are usually quite brittle at the temperatures encountered on a turbine blade surface, they can crack, especially when the temperature of the blade changes and differential thermal contraction and expansion stresses are set up between alloy and oxide. These can act as ideal nucleation centres for thermal fatigue cracks and, because oxide layers in nickel alloys are stuck well to the underlying alloy (they would be useless if they were not), the crack can spread into the alloy itself (Fig. 22.3). The properties of the oxide film are thus very important in affecting the fatigue properties of the whole component. 

The outstanding properties of copper-base materials are high electrical and thermal conductivity, good durabihty in mildly corrosive chemical environments and excellent ductility for forming complex shapes. As a relatively weak material, copper is often alloyed with zinc (brasses), tin (bronzes), aluminum and nickel to improve its mechanical properties and corrosion resistance. 

Nickel-iron alloys have a number of important applications that are derived from such special physical properties as their unique magnetic characteristics in the regions of 35, 50 and 80% nickel and from their abnormally low thermal expansion in the region of 36-50% nickel. Although not specifically used as corrosion-resistant materials, their high resistance to attack from many common environments is of benefit in their specialised applications. 

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