Samarium and Cobalt - Comparison - Properties

This article contains comparison of key thermal and atomic properties of samarium and cobalt, two comparable chemical elements from the periodic table. It also contains basic descriptions and applications of both elements. Samarium vs Cobalt.

samarium and cobalt - comparison

Compare samarium with another element

Compare cobalt with another element

Samarium and Cobalt – About Elements

Samarium

Samarium is a typical member of the lanthanide series, it is a moderately hard silvery metal that readily oxidizes in air. The name samarium is after the mineral samarskite from which it was isolated. Although classified as a rare earth element, samarium is the 40th most abundant element in the Earth’s crust and is more common than such metals as tin. In nuclear industry, especially natural and artificial samarium 149 has an important impact on the operation of a nuclear reactor. Samarium 149 has a very large neutron capture cross-section (about 42 000 barns). Since natural samarium contains about 14% of 149Sm, it can be used as an absorbing material in control rods.

Cobalt

Cobalt is found in the Earth’s crust only in chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, produced by reductive smelting, is a hard, lustrous, silver-gray metal.

Samarium in Periodic Table

Cobalt in Periodic Table

Source: www.luciteria.com

Samarium and Cobalt – Applications

Samarium

Samarium is mainly used in preparing samarium-cobalt alloy magnets for electric guitars, small motors and headphones. Samarium-cobalt magnets are much more powerful than iron magnets. They remain magnetic at high temperatures and so are used in microwave applications. They enabled the miniaturisation of electronic devices. However, neodymium magnets are now more commonly used instead. Its oxide is used for manufacturing special infrared adsorbing glass for carbon arc-lamp electrodes. It is useful in doping calcium fluoride crystals employed in optical lasers.

Cobalt

Cobalt has been used in many industrial, commercial, and military applications. Cobalt is primarily used in lithium-ion batteries, and in the manufacture of magnetic, wear-resistant and high-strength alloys. Cobalt-based Superalloys. This class of alloys is relatively new. In 2006, Sato et al. discovered a new phase in the Co–Al–W system. Unlike other superalloys, cobalt-base alloys are characterized by a solid-solution-strengthened austenitic (fcc) matrix in which a small quantity of carbide is distributed. While not used commercially to the extent of Ni-based superalloys, alloying elements found in research Co-based alloys are C, Cr, W, Ni, Ti, Al, Ir, and Ta. They possess better weldability and thermal fatigue resistance as compared to nickel based alloy. Moreover, they have excellent corrosion resistance at high temperatures (980-1100 °C) because of their higher chromium contents. Several cobalt compounds are oxidation catalysts. Typical catalysts are the cobalt carboxylates (known as cobalt soaps). They are also used in paints, varnishes, and inks as “drying agents” through the oxidation of drying oils.

Samarium and Cobalt – Comparison in Table

Element	Samarium	Cobalt
Density	7.353 g/cm3	8.9 g/cm3
Ultimate Tensile Strength	124 MPa	900 MPa
Yield Strength	110 MPa	220 MPa
Young’s Modulus of Elasticity	49.7 GPa	209 GPa
Mohs Scale	N/A	5
Brinell Hardness	441 MPa	800 MPa
Vickers Hardness	412 MPa	1040 MPa
Melting Point	1074 °C	1495 °C
Boiling Point	1900 °C	2927 °C
Thermal Conductivity	19 W/mK	100 W/mK
Thermal Expansion Coefficient	12.7 µm/mK	14 µm/mK
Specific Heat	0.2 J/g K	0.42 J/g K
Heat of Fusion	8.63 kJ/mol	16.19 kJ/mol
Heat of Vaporization	192 kJ/mol	376.5 kJ/mol