Refractory Metals: Part One
As a group they provide a number of unique characteristics – such as resistance to high heat, corrosion and wear – making them useful in a multitude of applications.Refractory metals have one characteristic in common: an exceptionally high melting point. Tungsten, for example, melts at 3410°C (6170°F), which is more than double that of iron and ten times that of lead.
Refractory Metals: Part Two
Tantalum is soluble in fused alkalis, insoluble in sulfuric, hydrochloric, and nitric acids, and soluble in hydrofluoric acid. It ignites in air to form tantalum pentoxide (sometimes referred to as tantalum (V) oxide or tantalic acid anhydride).Tantalum belongs to the group of metals that includes vanadium and niobium. It occurs mainly in the mineral tantalite (see Columbite), FeTa2O6.
Tungsten represents one of the most important refractory metals, consumed primarily in four distinct forms: tungsten carbide (65% of consumption), alloying additions, pure tungsten, and tungsten-based chemicals. Tungsten carbide, combined with cobalt binders to form cemented carbides, dominates cutting and wear applications due to its exceptional hardness and thermal stability. Metallic tungsten and tungsten alloys account for 16% of consumption, serving high-density applications including kinetic energy penetrators.
Silicon Carbide (SiC)
Silicon carbide (SiC) is a remarkable compound of carbon and silicon, initially produced through a high-temperature electrochemical reaction between sand and carbon. Its exceptional properties—including high-temperature strength, oxidation resistance, thermal shock resistance, and hardness—make it one of the most promising structural materials for diverse applications.
Silver and its alloys represent crucial materials in both decorative and industrial applications. While traditionally known for jewelry and tableware, over half of global silver demand now comes from industrial uses, particularly in electronics.