Source: Johnson Matthey

Platinum Group Metals

• strength and durability
• rarity
• strong catalytic properties
• resistance to oxidation and corrosion
• conductivity and ductility
• high melting point

Referred to as the "noble metals" in the periodic table of elements due to their rarity and unique properties, PGM’s are extremely efficient and durable. PGM’s are at the centre of technological advances in the fields of autocatalysts, power generation, alternative fuel sources (fuel cells), transportation, electronics and healthcare.

The largest PGM deposits are found primarily in South Africa and Russia, while North America accounts for a lesser proportion of PGM output. South Africa is the primary producer of platinum with palladium as a by-product whereas Russia produces palladium as a by-product of nickel. 

When recycled, over 96% of PGMs are recovered through highly-efficient refining techniques. Their recyclability means that they have a uniquely long lifecycle, allowing them to contribute significantly to the protection of the environment by reducing any negative impact which is normally associated with metal waste disposal.

Chemical Properties of PGM Metals

	Platinum	Palladium	Rhodium
Chemical Symbol	Pt	Pd	Rh
Density (g/cm3)	21.45	12.02	12.41
Melting point (°C)	1,769	1,554	1,960
Vickers hardness no.*	41	41	101
Electrical resistivity (microhm.cm at 0°C)	9.85	9.93	4.33
Thermal conductivity (watts/metre/°C)	73	76	150
Tensile strength* (kg/mm2)	14	17	71

The six platinum group metals (PGMs) are chemically very similar while platinum, iridium and osmium are among the densest. Platinum is 11% denser than gold and about twice the weight of silver or lead. Palladium, rhodium and ruthenium are lighter with palladium having about the same density as silver.

Platinum and Palladium are soft, ductile and resistant to oxidation and high temperature corrosion. They have widespread catalytic uses. In industry they are often used with the addition of other metals, including other PGMs.

Rhodium and Iridium present challenges to work with, but are valuable alone as well as in alloys. Their chemical compounds have many uses, and rhodium is a particularly good catalyst.

Ruthenium and Osmium are hard, brittle and almost unworkable in the metallic state, with poor oxidation resistance, but are valuable as additions to other metals, usually other PGMs, and as catalysts.

	Iridium	Ruthenium	Osmium
Chemical Symbol	Ir	Ru	Os
Density (g/cm3)	22.65	12.45	22.61
Melting point (°C)	2,443	2,310	3,050
Vickers hardness no.*	220	240	350
Electrical resistivity (microhm.cm at 0°C)	4.71	6.80	8.12
Thermal conductivity (watts/metre/°C)	148	105	87
Tensile strength* (kg/mm2)	112	165	-