heelp Consider the following two solidification processes for molten silica (SiO
ID: 822591 • Letter: H
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heelp
Consider the following two solidification processes for molten silica (SiO2). A liquid sample of SiO2 is cooled slowly to room temperature, forming a crystalline solid. A liquid sample of SiO2 is cooled very quickly to room temperature, forming a non crystalline solid. Explain why the silica solidified by slow cooling was able to form a crystalline structure. Explain why each of the following methods increases the carburization rate of steel. Recall that carburization depends on C atoms being able to diffuse into the metal surface. Using a high temperature. Using a finer-grained steel, in other words, metal with smaller grains so the grain density is higher.Explanation / Answer
1.) In crystalline silica, atoms are arranged in a regularly repeating pattern in three dimensions (i.e., they have long-range order). In contrast, in amorphous materials, the atoms exhibit only short-range order.So, A crystalline form of SiO2 results when molten silica is slowly cooled from a temperature because slow cooling gives sufficient time for ordered arrangement.On other hand, rapid cooling favors noncrystalline formation since time is not allowed for ordered arrangements to form.
2 a) Higher temperature means higher the velocity of C atoms which increases the rate of diffusion of C atoms into metal surfaces thus increasing the carburization rate of steel.
b) Using a finer-grained steel,means more effective area for C to diffuse which increases the rate of diffusion of C atoms.
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