Silicon is a hard and brittle crystalline solid with a blue-grey metallic lustre, it is a tetravalent metalloid and semiconductor.
|Phase at STP||Solid|
|Ultimate Tensile Strength||170 MPa|
|Yield Strength||165 MPa|
|Young’s Modulus of Elasticity||150 GPa|
|Brinell Hardness||2300 MPa|
|Melting Point||1410 °C|
|Boiling Point||3265 °C|
|Thermal Conductivity||148 W/mK|
|Thermal Expansion Coefficient||2.6 µm/mK|
|Specific Heat||0.71 J/g K|
|Heat of Fusion||50.55 kJ/mol|
|Heat of Vaporization||384.22 kJ/mol|
|Electrical resistivity [nanoOhm meter]||2.3E12|
|Magnetic Susceptibility||−3.9e-6 cm^3/mol|
Applications of Silicon
Most silicon is used industrially without being purified, and indeed, often with comparatively little processing from its natural form. Silicon is a vital ingredient in aluminum, steel, and iron alloys. It is added as a fluxing agent for copper alloys. In the form of clay and sand, it is used to manufacture bricks and concrete; it is a valuable refractory material for high-temperature work, for example, molding sands for castings in foundry applications. Silica is used to make fire brick, a type of ceramic. Silicate minerals are also in whiteware ceramics, an important class of products usually containing various types of fired clay minerals (natural aluminium phyllosilicates). An example is porcelain, which is based on the silicate mineral kaolinite. Traditional glass (silica-based soda-lime glass) also functions in many of the same ways, and also is used for windows and containers. Hyperpure silicon metal and doped hyperpure silicon (doping with boron, phosphorous, gallium, or arsenic) are used in solar cells, transistors and semiconductors.
Production and Price of Silicon
Raw materials prices change daily. They are primarily driven by supply, demand and energy prices. In 2019, prices of pure Silicon were at around 500 $/kg.
Second only to oxygen, silicon is the most abundant element in Earth’s crust. It is found in rocks, sand, clays and soils, combined with either oxygen as silicon dioxide, or with oxygen and other elements as silicates. Silicon’s compounds are also found in water, in the atmosphere, in many plants, and even in certain animals. Silicon of 96–99% purity is made by reducing quartzite or sand with highly pure coke. The reduction is carried out in an electric arc furnace.
Mechanical Properties of Silicon
Strength of Silicon
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 Silicon
Ultimate tensile strength of Silicon is 170 MPa.
Yield Strength of Silicon
Yield strength of Silicon is 165 MPa.
Modulus of Elasticity of Silicon
The Young’s modulus of elasticity of Silicon is 150 GPa.
Hardness of Silicon
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 Silicon is approximately 2300 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 Silicon 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.
Silicon is has a hardness of approximately 7.
See also: Hardness of Materials
Silicon – Crystal Structure
A possible crystal structure of Silicon is face-centered diamond-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 Silicon
Silicon – Melting Point and Boiling Point
Melting point of Silicon is 1410°C.
Boiling point of Silicon is 3265°C.
Note that, these points are associated with the standard atmospheric pressure.
Silicon – Thermal Conductivity
Thermal conductivity of Silicon is 148 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 Silicon
Linear thermal expansion coefficient of Silicon is 2.6 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.
Silicon – Specific Heat, Latent Heat of Fusion, Latent Heat of Vaporization
Specific heat of Silicon is 0.71 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 Silicon is 50.55 kJ/mol.
Latent Heat of Vaporization of Silicon is 384.22 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.
Silicon – 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 Silicon
Electrical resistivity of Silicon is 2.3E12 nΩ⋅m.
Electrical conductivity and its converse, electrical resistivity, is a fundamental property of a material that quantifies how Silicon conducts the flow of electric current. Electrical conductivity or specific conductance is the reciprocal of electrical resistivity.
Magnetic Susceptibility of Silicon
Magnetic susceptibility of Silicon is −3.9e-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 Silicon in response to an applied magnetic field.
Application and prices of other elements