Zone refining and phase diagrams

In summary, to solve the problem, you can use the equation for C_s that you derived and plug in the values of k and xL. To incorporate the C_l term, you can use the equation C_l = C_o - C_s or C_l = k*C_o*exp(-xL/k).
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twohaha
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Homework Statement



From Ashby's "Engineering Materials"[/B]
upload_2016-1-25_13-37-45.png


upload_2016-1-25_13-37-55.png


Homework Equations


[itex]k=C_o/C_s=m_1/m_2[/itex]
upload_2016-1-25_13-39-37.png

The Attempt at a Solution


Solving for k
[itex]m_1=(660-548)/(0-32)=-3.5[/itex]
[itex]m_2=(660-548)/(0-7)=-16[/itex]
[itex]k=m_1/m_2=0.219[/itex]

[itex]C_s=C_o*(1-(1-0.219)exp(-xL/0.219))[/itex]How do I proceed from there? Also, how do I incorporate the [itex] C_l [/itex] term in the equation?

Thanks!
 

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To proceed, you can use the equation for C_s that you have derived and plug in the value of k that you calculated. Then, you can also plug in the value of xL for the specific material you are working with. This will give you the value of C_s for that material.

To incorporate the C_l term, you can use the equation C_l = C_o - C_s, where C_o is the initial concentration and C_s is the concentration at a specific distance xL. This will give you the concentration gradient of the material at that specific distance.

Alternatively, you can also use the equation C_l = k*C_o*exp(-xL/k), where k is the same constant that you calculated earlier. This equation takes into account the concentration gradient and can be used to calculate the concentration at any distance xL.

Hope this helps!
 

FAQ: Zone refining and phase diagrams

What is zone refining and how does it work?

Zone refining is a process used to purify materials by creating a controlled temperature gradient along a solid material. This causes impurities to move towards one end of the material, leaving behind a more pure substance. The impurities can then be removed, resulting in a more pure material. This process is commonly used in the semiconductor industry to produce highly pure silicon for electronic devices.

What are the advantages of using zone refining over other purification methods?

Zone refining has several advantages over other purification methods. First, it is a relatively simple and low-cost process. It also allows for high purity levels to be achieved, often over 99.9999%. Additionally, it is a continuous process, meaning large quantities of material can be purified at once.

What are the different phases of matter and how do they relate to phase diagrams?

The three main phases of matter are solid, liquid, and gas. A phase diagram is a graphical representation of how these phases change with varying pressure and temperature. It shows the conditions under which a substance will exist as a solid, liquid, or gas, and also where phase transitions occur between these phases.

How are impurities removed during the zone refining process?

Impurities are removed during the zone refining process by creating a temperature gradient along the material. As the material is heated, the impurities will move towards the hotter end, leaving behind a more pure substance. The pure substance can then be collected and the process can be repeated to further purify the material.

Can zone refining be used for all types of materials?

Zone refining is most commonly used for purifying semiconductors, such as silicon and germanium. However, it can also be used for other materials such as metals and alloys. The effectiveness of the process may vary depending on the material's properties and impurity levels.

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