Platinum is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal. Platinum is one of the least reactive metals. It has remarkable resistance to corrosion, even at high temperatures, and is therefore considered a noble metal. Platinum is used in catalytic converters, laboratory equipment, electrical contacts and electrodes, platinum resistance thermometers, dentistry equipment, and jewelry.
|Element category||Transition Metal|
|Phase at STP||Solid|
|Ultimate Tensile Strength||150 MPa|
|Yield Strength||70 MPa|
|Young’s Modulus of Elasticity||168 GPa|
|Brinell Hardness||400 MPa|
|Vickers Hardness||550 MPa|
|Melting Point||1772 °C|
|Boiling Point||3827 °C|
|Thermal Conductivity||72 W/mK|
|Thermal Expansion Coefficient||8.8 µm/mK|
|Specific Heat||0.13 J/g K|
|Heat of Fusion||19.6 kJ/mol|
|Heat of Vaporization||510 kJ/mol|
|Electrical resistivity [nanoOhm meter]||105|
|Magnetic Susceptibility||+201e-6 cm^3/mol|
Applications of Platinum
Platinum is primarily an industrial metal. It is a critical material for many industries and is considered a strategic metal. Platinum is used as a catalyst, platinum is mostly found in vehicle catalytic converters that reduce toxic exhaust chemicals, and also in fuel cells to increase efficiency. The most common use of platinum is as a catalyst in chemical reactions, often as platinum black. In catalytic converters, platinum allows the complete combustion of low concentrations of unburned hydrocarbons from the exhaust into carbon dioxide and water vapor. Platinum has been used in thermocouple devices that measure temperature with high accuracy. Platinum is a component in magnetic coatings for high-density hard disk drives and some of the newer optical storage systems.
Production and Price of Platinum
Raw materials prices change daily. They are primarily driven by supply, demand and energy prices. In 2019, prices of pure Platinum were at around 31500 $/kg.
Platinum, along with the rest of the platinum-group metals, is obtained commercially as a by-product from nickel and copper mining and processing. During electrorefining of copper, noble metals such as silver, gold and the platinum-group metals as well as selenium and tellurium settle to the bottom of the cell as “anode mud”, which forms the starting point for the extraction of the platinum-group metals. Of the 218 tonnes of platinum sold in 2014, 98 tonnes were used for vehicle emissions control devices (45%), 74.7 tonnes for jewelry (34%), 20.0 tonnes for chemical production and petroleum refining (9.2%), and 5.85 tonnes for electrical applications such as hard disk drives (2.7%). As of 2020, the value of platinum is around $32.00 per gram ($1,000 per troy ounce).
Mechanical Properties of Platinum
Strength of Platinum
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 Platinum
Ultimate tensile strength of Platinum is 150 MPa.
Yield Strength of Platinum
Yield strength of Platinum is 70 MPa.
Modulus of Elasticity of Platinum
The Young’s modulus of elasticity of Platinum is 70 MPa.
Hardness of Platinum
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 Platinum is approximately 400 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 Platinum is approximately 550 MPa.
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.
Platinum is has a hardness of approximately 3.5.
See also: Hardness of Materials
Platinum – Crystal Structure
A possible crystal structure of Platinum 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 Platinum
Platinum – Melting Point and Boiling Point
Melting point of Platinum is 1772°C.
Boiling point of Platinum is 3827°C.
Note that, these points are associated with the standard atmospheric pressure.
Platinum – Thermal Conductivity
Thermal conductivity of Platinum is 72 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 Platinum
Linear thermal expansion coefficient of Platinum is 8.8 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.
Platinum – Specific Heat, Latent Heat of Fusion, Latent Heat of Vaporization
Specific heat of Platinum 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 Platinum is 19.6 kJ/mol.
Latent Heat of Vaporization of Platinum is 510 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.
Platinum – 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 Platinum
Electrical resistivity of Platinum is 105 nΩ⋅m.
Electrical conductivity and its converse, electrical resistivity, is a fundamental property of a material that quantifies how Platinum conducts the flow of electric current. Electrical conductivity or specific conductance is the reciprocal of electrical resistivity.
Magnetic Susceptibility of Platinum
Magnetic susceptibility of Platinum is +201e-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 Platinum in response to an applied magnetic field.
Application and prices of other elements