History of Technology in India, Vol. I: From Antiquity to c. 1200 A.D. v1.c13.s2.t8.11

v1.c13.s2.t8.11

The chemical analysis of ancient metal artifacts have revealed the presence of many other elements in minute quantities affecting the properties of the parent metal many a times favourably. For example the copper artifacts containing 2-5% Arsenic have been reported to have better hardness than pure copper but it is difficult to say whether this alloy originated from the arsenic bearing complex sulphide ore or Arsenic metal deliberately added to copper to produce this alloy. In exceptional cases copper containing 20-24% Arsenic have been reported and this must have been definitely made by alloying. Most probably the acquaintance with first alloy might have been accidental due to the coexistence and co-reduction of two or more metals but after observing the beneficial effect on strength, hardness, hot and cold workability, lusture and corrosion resistance ancient craftsmen must have started adding these metal deliberately and thus the alloy technology must have been born. The acquaintance with the naturally occurring Au-Ag alloy ‘Electrum’ found at Kolar might have been the first introduction of Indians to the difference between the property of pure Gold and Au-Ag alloy. The history of production technology of alloys most probably begins with the manufacture of bronze or Fe-C alloys of known composition, but it is difficult to say which one of these was developed first because in India according to the Indian Archaeologists bronze and iron have an overlapping growth. Dube and Prakash(1970) have studied the analysis of the ancient Harappan bronze objects and they have concluded that these alloys of Cu+Sn were not a result of chance intermixing but designed to develop certain specific properties. Biswas(1981) has reviewed *Rasa Ratna Samuccaya* and noted that the alloy of two metals were called *Durmela lohadvayametañca* if the additives were incompatible otherwise it was known as *dvandvana*. The process of addition to the liquid metal was known as *Niravapana*, and an alloy containing five metals was called *Pañcaloha* or *Vartaloha*. Many specific alloys have been given a separate name such as brass was called ‘Suvarnaka’ and Cu-Pb alloy *Sulvanage*. The objective of alloying could have been one or more of the following: