The bronzes are also vulnerable to bacterial corrosion

  Ancient wrought iron (block iron smelting) is composed of ferrite, ferrite solid solution of carbon low, was cavernous stomatal loose structure, easy to penetrate the air-water variety of pollution, therefore corrosion-resistant ability of poor. The ancient white pig iron is composed of ferrite and cementite. The cementite general uneven distribution of the content of the alloy surface is greater than the alloy. Although it is in the alloy surface layer of protective film, but cementite between the ferrite serious contorted phenomenon between the two micro-crack gap can still make it to corrode. From south to north around China the bronze store have the monotony of goods.
    Cementite is a very stable compound, under certain conditions will be broken down into iron and graphite. Gray iron and malleable cast iron in ancient China, a large number of graphite, graphite layers between the cracks and holes, harmful molecules into the Bronze deep inside the channel, poor corrosion resistance. They pay no attention to the development of personality characteristics and patent protection about the bronze. The ancient steel by repeated forging porous less, and the protection of cementite, so there is a strong resistance to corrosion. However, due to the iron body has a more active chemical properties of the iron electrode potential of the various organizations, it will cause electrochemical corrosion
    Bronze in a humid environment, a very easily oxidized up to brown rust. Combined with the ancient smelting, casting, technical level restrictions bronze metal loose tissue, high porosity. These gaps can store large amounts of water, the iron corrosion process intensified, accelerated. Rusty bronze in contact with the nature of chloride can be formed in the Bureau of part of the bronze micro battery, chemical corrosion, chloride plays the role of the electrolyte in the corrosion process. Between the rust and iron potential, through the electrolyte to the electrochemical reaction, the reaction of iron metal ion in the reaction, so that the objects matrix have been seriously eroded. Even more, they lack the leading person to take the lead to organize the Chinese bronze to sell abroad.
    In addition, the bronzes are also vulnerable to bacterial corrosion. Sulfate-reducing bacteria in the soil can be used to restore the hydrogen produced in the electrochemical corrosion of sulfate in the soil, making it the erosion of metallic iron sulfide. Sulfide corrosion of bronze surface of the porous black iron sulfide. To the late Shang and early Western Zhou Dynasty, the technology of bronze smelting and casting has reached a peak.  Same time, due to bacterial corrosion, oxygen atoms are oxidized to the hydroxide ion, in order to clear the extreme chemical reaction of cathode hydrogen can slow down the electrochemical corrosion electrochemical corrosion Yuyan crack.