![]() Zinc was added in the twelfth century to form silvery and rust-resisting alloy known as paktong (white copper), which was widely used in Europe before stainless steel was invented. When the sulfide ores of copper and nickel were smelted together, it led to copper–nickel alloy in the fourth century in China. This is an early application of an intermetallic. Archaeo-metallurgical investigations by Sharada Srinivasan on vessels from South Indian megaliths of the Nilgiris and Adichanallur (1000–500 bce) showed that they were of wrought and quenched high-tin beta bronze, ranking among the earliest known artifacts. Mirrors were made of bronzes in different parts of the Old World including India and China, due to their higher hardness which makes it easy in getting mirror finish to reflect like silver. It is interesting to mention that intermetallics of copper–tin alloys had been used in ancient time. The eighth metal, zinc, is added because of the unique Indian context but also because the discovery of other metals had to await the advent of the scientific revolution for a few centuries. The seven metals found in antiquity were gold, copper, silver, iron, lead, tin, and mercury. A more intentional alloying of tin with copper (tin bronzes in 2500 bce) gave birth to the Bronze Age, as bronze was superior in its mechanical properties. The first alloy of copper and arsenic (Arsenical bronze, 3000 bce) was entirely accidental. In the primitive fires in the caves, ores of copper got mixed with ores of arsenic, zinc, and tin. It is an early example of multicomponent high-entropy alloys (HEAs), since platinum is often found as alloys with the other platinum group metals and iron mostly.Īlloying was an accidental discovery. Also, mixtures of platinum metals are found to occur in nature. When platinum was discovered in 1735, it was compared with silver. Native alloys such as tumbaga and electrum are alloys of gold–copper and gold–silver, respectively. Ranganathan, in High Entropy Alloys, 2014 1.2 The Coming of Alloys
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