Re: [Phys-L] magnetic field reversals

["John Clement" <clement@hal-pc.org>]

I have seen that old bar magnets tend to be weak the next year and need some
refreshment.  We didn't have new bar magnets.  The commercial magnetisers
worked well.

John M. Clement
Houston, TX 

> -----Original Message-----
> From: Phys-l [mailto:phys-l-bounces@www.phys-l.org] On Behalf 
> Of Bernard Cleyet
> Sent: Monday, October 05, 2015 4:03 PM
> To: Phys-L@Phys-L.org
> Subject: Re: [Phys-L] magnetic field reversals
>
>
> On 2015, Oct 05, , at 13:13, John Clement <clement@hal-pc.org> wrote:
>
> > Old bar magnets do not hold their
> > magnetism very well, so you have to use a magnetizer fairly 
> frequently 
> > on them.  I would say that mususe of the magnetizer may be 
> a real possibility.
> > I did not always have access to a magnetizer so I would 
> carefully use 
> > ceramic magnets to "refresh" the bar magnets.
>
>
> antique bars softer than alnico? 
>
> Ceramics very approximately 5X alnico.  
>
>
> https://en.wikipedia.org/wiki/Coercivity  
>
> https://en.wikipedia.org/wiki/Coercivity  
>
>
> bc
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