What is this component in the HD?

[harddriveuser]

Hi, when I opened some hard drives bought 10-20 years ago, I found that there is a metallic component covering a small portion of the HD plate. Anybody knows what is name?

http://postimg.org/image/feldf48c9/53effe01/

 

[CountMike]

Looks like magnetic shield over heads swing arm.

 

[harddriveuser]

Thanks. What does the magnetic shield do? What is it made of?

 

[CountMike]

There are magnets and quite powerful ones inside head movement mechanism that moves heads. It's field has to be contained because magnet can erase data on disks. It should be made of soft iron because steel can be magnetized but soft (elementary) iron can't but does stop magnetic field. Nickel is like that too.

 

[harddriveuser]

Thanks. I want to make sure that we are talking about the same thing. I am referring to the highlighted plate. Could you please double check? I want to know exactly what material is that. Thanks.

http://postimg.org/image/4uazd5mwp/

 

[CountMike]

Sorry, can't tell you but one thing is for sure, a magnet may stick to it but it can't be magnetized. Many composite metals fit that bill.