History of Technology in India, Vol. I: From Antiquity to c. 1200 A.D. v1.c13.s2.t11.10

v1.c13.s2.t11.10

The alloys in this range contain Zn from 5 to 20% and they can be cast and cold or hot worked, and these have a very low M.P. i.e. only 750°C. Brasses having higher Zn content have been rarely reported from ancient sources. These are called α- β brass and they can be generally used only in as cast condition. These alloys are characterised by their Gold like colour and capacity to take very shining polish. These could be easily gilded with Gold. On storage of alkalies or food having organic acids the food gets stale in short time and the surface of the pot tarnishes black, giving out foul smell. This metal is also subjected to a special type of corrosion on storage i.e. Dezincification. Many brass objects found during archaeological excavations have suffered from this type of corrosion and got converted into a lump of copper powder, due to the loss of Zn with time. In RRS two type of brass have been mentioned ‘Ritika’ and ‘Kakatundi’: on coming in contact with hot lemon juice (Kanjika) Ritika used to turn copper red whereas Kakatundi used to become black.