Browse Prior Art Database

Cracking of Ferrite Material

IP.com Disclosure Number: IPCOM000059853D
Original Publication Date: 1986-Jan-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Bhushan, B: AUTHOR [+4]

Abstract

For proper formation of ferrite heads, it is essential that the surface of the head be as smooth as possible and free of surface defects. It has been discovered that a suitably scribed square bulk ferrite material can be fractured to provide such a surface.

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Cracking of Ferrite Material

For proper formation of ferrite heads, it is essential that the surface of the head be as smooth as possible and free of surface defects. It has been discovered that a suitably scribed square bulk ferrite material can be fractured to provide such a surface.

In the Figure, bulk ferrite specimen 1 has a square cross section and is provided with a relatively blunt scratch 2 on one surface. Specimen 1 is then inserted in fixture 3 that enables specimen 1 to be subjected to high fluid pressure in the vicinity of scratch 2. Nylon cord 4, similar to that used for "O" ring seals, is provided in grooves in fixture 3 on either side of the region to be pressurized. Fluid pressure is then provided through a suitable fitting at 5 and increased until a crack 6 initiates at scratch 2 and runs abruptly across the specimen. The quality of the cracked surface (flatness and smoothness) increases with the energy stored before fracture. This in turn is proportional to the pressure required. It is therefore important that the initial scratch 2 be a relatively blunt one of low stress concentration so that a high pressure will be required to initiate the sharp crack that runs across the specimen. The pressure required to produce a suitable cracked surface in a typical ferrite is between 12 and 15 Kpsi (83 to 103 MPa).

Disclosed anonymously.

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