Lead is a heavy metal that is denser than most common materials. Lead is soft and malleable, and has a relatively low melting point. Lead is widely used as a gamma shield. Major advantage of lead shield is in its compactness due to its higher density. Lead has the highest atomic number of any stable element and concludes three major decay chains of heavier elements.
|Element category||Poor Metal|
|Phase at STP||Solid|
|Ultimate Tensile Strength||17 MPa|
|Yield Strength||5.5 MPa|
|Young’s Modulus of Elasticity||16 GPa|
|Brinell Hardness||38 MPa|
|Melting Point||327.5 °C|
|Boiling Point||1740 °C|
|Thermal Conductivity||35 W/mK|
|Thermal Expansion Coefficient||28.9 µm/mK|
|Specific Heat||0.13 J/g K|
|Heat of Fusion||4.799 kJ/mol|
|Heat of Vaporization||177.7 kJ/mol|
|Electrical resistivity [nanoOhm meter]||208|
|Magnetic Susceptibility||−23e-6 cm^3/mol|
Applications of Lead
Lead metal has several useful mechanical properties, including high density, low melting point, ductility, and relative inertness. Lead is widely used for car batteries, pigments, ammunition, cable sheathing, weights for lifting, weight belts for diving, lead crystal glass, radiation protection and in some solders. The largest use of lead in the early 21st century is in lead–acid batteries. The lead in batteries undergoes no direct contact with humans, so there are fewer toxicity concerns. Lead is used in high voltage power cables as sheathing material to prevent water diffusion into insulation; this use is decreasing as lead is being phased out. A lead is widely used as a gamma shield. Major advantage of lead shield is in its compactness due to its higher density. On the other hand depleted uranium is much more effective due to its higher Z. Depleted uranium is used for shielding in portable gamma ray sources.
Production and Price of Lead
Raw materials prices change daily. They are primarily driven by supply, demand and energy prices. In 2019, prices of pure Lead were at around 15 $/kg.
As of 2014, production of lead is increasing worldwide due to its use in lead–acid batteries. There are two major categories of production: primary from mined ores, and secondary from scrap. In 2014, 4.58 million metric tons came from primary production and 5.64 million from secondary production. The top three producers of mined lead concentrate in that year were China, Australia, and the United States.
Mechanical Properties of Lead
Strength of Lead
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.
See also: Strength of Materials
Ultimate Tensile Strength of Lead
Ultimate tensile strength of Lead is 17 MPa.
Yield Strength of Lead
Yield strength of Lead is 5.5 MPa.
Modulus of Elasticity of Lead
The Young’s modulus of elasticity of Lead is 5.5 MPa.
Hardness of Lead
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.
Brinell hardness of Lead is approximately 38 MPa.
The Vickers hardness test method was developed by Robert L. Smith and George E. Sandland at Vickers Ltd as an alternative to the Brinell method to measure the hardness of materials. The Vickers hardness test method can be also used as a microhardness test method, which is mostly used for small parts, thin sections, or case depth work.
Vickers hardness of Lead is approximately N/A.
Scratch hardness is the measure of how resistant a sample is to permanent plastic deformation due to friction from a sharp object. The most common scale for this qualitative test is Mohs scale, which is used in mineralogy. The Mohs scale of mineral hardness is based on the ability of one natural sample of mineral to scratch another mineral visibly.
Lead is has a hardness of approximately 1.5.
See also: Hardness of Materials
Lead – Crystal Structure
A possible crystal structure of Lead is face-centered cubic structure.
In metals, and in many other solids, the atoms are arranged in regular arrays called crystals. A crystal lattice is a repeating pattern of mathematical points that extends throughout space. The forces of chemical bonding causes this repetition. It is this repeated pattern which control properties like strength, ductility, density, conductivity (property of conducting or transmitting heat, electricity, etc.), and shape. There are 14 general types of such patterns known as Bravais lattices.
See also: Crystal Structure of Materials
Thermal Properties of Lead
Lead – Melting Point and Boiling Point
Melting point of Lead is 327.5°C.
Boiling point of Lead is 1740°C.
Note that, these points are associated with the standard atmospheric pressure.
Lead – Thermal Conductivity
Thermal conductivity of Lead is 35 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.
Coefficient of Thermal Expansion of Lead
Linear thermal expansion coefficient of Lead is 28.9 µm/(m·K)
Thermal expansion is generally the tendency of matter to change its dimensions in response to a change in temperature. It is usually expressed as a fractional change in length or volume per unit temperature change.
Lead – Specific Heat, Latent Heat of Fusion, Latent Heat of Vaporization
Specific heat of Lead is 0.13 J/g K.
Heat capacity is an extensive property of matter, meaning it is proportional to the size of the system. Heat capacity C has the unit of energy per degree or energy per kelvin. When expressing the same phenomenon as an intensive property, the heat capacity is divided by the amount of substance, mass, or volume, thus the quantity is independent of the size or extent of the sample.
Latent Heat of Fusion of Lead is 4.799 kJ/mol.
Latent Heat of Vaporization of Lead is 177.7 kJ/mol.
Latent heat is the amount of heat added to or removed from a substance to produce a change in phase. This energy breaks down the intermolecular attractive forces, and also must provide the energy necessary to expand the gas (the pΔV work). When latent heat is added, no temperature change occurs. The enthalpy of vaporization is a function of the pressure at which that transformation takes place.
Lead – Electrical Resistivity – Magnetic Susceptibility
Electrical property refers to the response of a material to an applied electric field. One of the principal characteristics of materials is their ability (or lack of ability) to conduct electrical current. Indeed, materials are classified by this property, that is, they are divided into conductors, semiconductors, and nonconductors.
See also: Electrical Properties
Magnetic property refers to the response of a material to an applied magnetic field. The macroscopic magnetic properties of a material are a consequence of interactions between an external magnetic field and the magnetic dipole moments of the constituent atoms. Different materials react to the application of magnetic field differently.
See also: Magnetic Properties
Electrical Resistivity of Lead
Electrical resistivity of Lead is 208 nΩ⋅m.
Electrical conductivity and its converse, electrical resistivity, is a fundamental property of a material that quantifies how Lead conducts the flow of electric current. Electrical conductivity or specific conductance is the reciprocal of electrical resistivity.
Magnetic Susceptibility of Lead
Magnetic susceptibility of Lead is −23e-6 cm^3/mol.
In electromagnetism, magnetic susceptibility is the measure of the magnetization of a substance. Magnetic susceptibility is a dimensionless proportionality factor that indicates the degree of magnetization of Lead in response to an applied magnetic field.
Application and prices of other elements