About Nickel Silver
Nickel silver, known also as German silver, nickel brass or alpacca, is a copper alloy with nickel and often zinc. UNS C75700 nickel silver 65-12 copper alloy has good corrosion and tarnish-resistance, and high formability. Nickel silver is named due to its silvery appearance, but it contains no elemental silver unless plated.
|Phase at STP||solid|
|Ultimate Tensile Strength||400 MPa|
|Yield Strength||170 MPa|
|Young’s Modulus of Elasticity||117 GPa|
|Brinell Hardness||90 BHN|
|Melting Point||1040 °C|
|Thermal Conductivity||40 W/mK|
|Heat Capacity||377 J/g K|
Composition of Nickel Silver
The usual formulation is 60% copper, 20% nickel and 20% zinc. For example the alloy C75700 contains 63.5 to 66.5% of Cu, 11.0 to 13.0% of Ni, 0.05% Pb max, 0.25% Fe max, 0.5% Mn max, and balance of Zn.
Applications of Nickel Silver
Nickel silver alloys are used for decorative applications, jewellery, model making, musical instruments (e.g., flutes, clarinets), flutes ball point refills, screws, rivets and fishing rods, test probes.
Mechanical Properties of Nickel Silver
Strength of Nickel Silver
In mechanics of materials, the strength of a material is its ability to withstand an applied load without failure or plastic deformation. Strength of materials basically considers the relationship between the external loads applied to a material and the resulting deformation or change in material dimensions. In designing structures and machines, it is important to consider these factors, in order that the material selected will have adequate strength to resist applied loads or forces and retain its original shape.
Strength of a material is its ability to withstand this applied load without failure or plastic deformation. For tensile stress, the capacity of a material or structure to withstand loads tending to elongate is known as ultimate tensile strength (UTS). Yield strength or yield stress is the material property defined as the stress at which a material begins to deform plastically whereas yield point is the point where nonlinear (elastic + plastic) deformation begins. In case of tensional stress of a uniform bar (stress-strain curve), the Hooke’s law describes behaviour of a bar in the elastic region. The Young’s modulus of elasticity is the elastic modulus for tensile and compressive stress in the linear elasticity regime of a uniaxial deformation and is usually assessed by tensile tests.
See also: Strength of Materials
Ultimate Tensile Strength of Nickel Silver
Ultimate tensile strength of Nickel Silver is 400 MPa.
Yield Strength of Nickel Silver
Yield strength of Nickel Silver is 170 MPa.
Modulus of Elasticity of Nickel Silver
The Young’s modulus of elasticity of Nickel Silver is 117 GPa.
Hardness of Nickel Silver
In materials science, hardness is the ability to withstand surface indentation (localized plastic deformation) and scratching. Brinell hardness test is one of indentation hardness tests, that has been developed for hardness testing. In Brinell tests, a hard, spherical indenter is forced under a specific load into the surface of the metal to be tested.
The Brinell hardness number (HB) is the load divided by the surface area of the indentation. The diameter of the impression is measured with a microscope with a superimposed scale. The Brinell hardness number is computed from the equation:
Brinell hardness of Nickel Silver is approximately 90 BHN (converted).
See also: Hardness of Materials
Thermal Properties of Nickel Silver
Nickel Silver – Melting Point
Melting point of Nickel Silver is 1040 °C.
Note that, these points are associated with the standard atmospheric pressure. In general, melting is a phase change of a substance from the solid to the liquid phase. The melting point of a substance is the temperature at which this phase change occurs. The melting point also defines a condition in which the solid and liquid can exist in equilibrium. For various chemical compounds and alloys, it is difficult to define the melting point, since they are usually a mixture of various chemical elements.
Nickel Silver – Thermal Conductivity
Thermal conductivity of Nickel Silver is 40 W/(m·K).
The heat transfer characteristics of a solid material are measured by a property called the thermal conductivity, k (or λ), measured in W/m.K. It is a measure of a substance’s ability to transfer heat through a material by conduction. Note that Fourier’s law applies for all matter, regardless of its state (solid, liquid, or gas), therefore, it is also defined for liquids and gases.
The thermal conductivity of most liquids and solids varies with temperature. For vapors, it also depends upon pressure. In general:
Most materials are very nearly homogeneous, therefore we can usually write k = k (T). Similar definitions are associated with thermal conductivities in the y- and z-directions (ky, kz), but for an isotropic material the thermal conductivity is independent of the direction of transfer, kx = ky = kz = k.
Nickel Silver – Specific Heat
Specific heat of Nickel Silver is 377 J/g K.
Specific heat, or specific heat capacity, is a property related to internal energy that is very important in thermodynamics. The intensive properties cv and cp are defined for pure, simple compressible substances as partial derivatives of the internal energy u(T, v) and enthalpy h(T, p), respectively:
where the subscripts v and p denote the variables held fixed during differentiation. The properties cv and cp are referred to as specific heats (or heat capacities) because under certain special conditions they relate the temperature change of a system to the amount of energy added by heat transfer. Their SI units are J/kg K or J/mol K.
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