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linux kid
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If it's a magnetic shield, then it must be permeable. Right or wrong? I would like to know if mumetal is permeable.
Yes, a superconductor expels flux (perfect diamagnetism) for fields below a critical value, and can act as a non-permeable magnetic shield.linux kid said:Is the a magnet shield that is NOT a permeable?
marcusl said:Yes, a superconductor expels flux (perfect diamagnetism) for fields below a critical value, and can act as a non-permeable magnetic shield.
marcusl said:First of all mumetal doesn't reflect fields at all, it shields by guiding them through the metal. Think of when you go camping and make a little ditch around your tent to conduct water away if it rains. The ditch doesn't reflect water, it guides it along. Designing magnetic shields isn't rocket science but there isn't a simple formula either--it depends on configuration and shape of both the field and the shield, and also on the strength of the field and thickness of the mumetal. The shielding effectiveness drops dramatically if you saturate the material in a strong field, in which case multi-layer shields are used.
Here are some sites to get you started. You'll find many more with a google search.
http://www.advancemag.com/" , click on "Shield Design".
Here's a vendor that sells small quantities of mterials
http://www.lessemf.com/mag-shld.html"
and they have a design guide.
http://www.magnetic-shield.com/dynamics/works.html"
linux kid said:Thanks marcus for the explanation. You bring me to more questions. In the camp scenario, the water can be redirected down a slope to a river or something. What about in the case of the fields? Where does it go, into the air? Do magnetic field build up (eg. like heat) or does it always stay at a certain level?
You can however, get some Type IIs on eBay or any good electromagnetic effects-themed scientific toy website. You also need to rent a dewar for liquid nitrogen.linux kid said:Where can I buy some, do you know?
ranger said:The field moves through the mumetal (picture the magnetic field like field lines) becuase it has higher magnetic permeability than the air around it. The field lines originate from the north pole of the magnet then "flow" to the south pole, through the magnet itself then back out the north pole. Placing mumetal in the vicinity will simply create a sort of like a different path for the fields lines, but it will still flow from north to south through the mumetal. Please keep in mind that fields lines are abstract entities that are used to visualize the magnetic fields.
1. Yes, it goes back into the air.linux kid said:Thanks marcus for the explanation. You bring me to more questions. In the camp scenario, the water can be redirected down a slope to a river or something. What about in the case of the fields? Where does it go, into the air? Do magnetic field build up (eg. like heat) or does it always stay at a certain level?
light_bulb said:i was thinking of making my own brick funace just for this, some sand, stone coal and an accordian blower lol.
Mumetal permeability refers to the ability of the alloy Mumetal to become magnetized in the presence of a magnetic field. This property is important because it allows Mumetal to be used in applications such as shielding against magnetic fields and in the production of sensitive electronic equipment.
No, Mumetal permeability is not always accurate. It depends on various factors such as the composition of the alloy, manufacturing process, and external magnetic fields. These factors can affect the permeability of Mumetal and result in variations in its performance.
Mumetal permeability is measured using a device called a permeameter. This device measures the magnetic flux density and the magnetic field strength of the alloy to determine its permeability. The measurement is usually done at different levels of magnetization to get a complete understanding of the alloy's permeability.
Yes, Mumetal permeability can be improved through various techniques such as heat treatment, cold working, and alloying. These methods can help to optimize the composition and structure of the alloy, resulting in higher permeability and better performance.
While Mumetal is a popular choice for its high permeability, it does have some drawbacks. The alloy is expensive, and its permeability can be affected by factors such as temperature and vibrations. Additionally, it has limited strength and may not be suitable for certain high-stress applications.