Annealing (metallurgy) brass can be cooled slowly in air, or quickly by quenching in water, unlike ferrous metals, such as steel, which must be cooled slowly to anneal. In this fashion, the metal is softened and prepared for further work—such as shaping, stamping, or forming. Annealing occurs by the diffusion of atoms within a solid material, so that the material progresses towards its equilibrium state. Heat increases the rate of diffusion by providing the energy needed to break bonds. The movement of atoms has the effect of redistributing and eradicating the dislocations in metals and (to a lesser extent) in ceramics. This
Ancient Chinese glass these forms were normally made out of lacquer or ceramic, although some jade vessels in those shapes are also known. All vessels were produced by mould casting. Ancient Chinese glass Ancient Chinese glass refers to all types of glass manufactured in China prior to the Qing Dynasty (1644–1911). In Chinese history, glass played a peripheral role in the arts and crafts, when compared to ceramics and metal work. The limited archaeological distribution and use of glass objects are evidence of the rarity of the material. Literary sources date the first manufacture of glass to the 5th century AD. However, the