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Coating for Permalloy Material

IP.com Disclosure Number: IPCOM000073960D
Original Publication Date: 1971-Feb-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Brock, GW: AUTHOR [+3]

Abstract

Magnetic read/write heads, or transducers, are normally constructed of magnetically permeable material supported within a housing. The magnetic material is often composed of permalloy. In use, the head, including small exposed pole tip portions of permalloy, is exposed to rubbing contact with magnetic recording media. Often, the relative velocity between the head and the media is quite high. This subjects the head to forces of wear and abrasion. These conditions can result in selective damage, similar to erosion, to the permalloy pole tips or to the supporting materials surrounding the permalloy. At high operational speeds, a transducer which has been eroded will cause the magnetic recording media to flutter, or have varying and uncontrolled head-to-media separation.

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Coating for Permalloy Material

Magnetic read/write heads, or transducers, are normally constructed of magnetically permeable material supported within a housing. The magnetic material is often composed of permalloy. In use, the head, including small exposed pole tip portions of permalloy, is exposed to rubbing contact with magnetic recording media. Often, the relative velocity between the head and the media is quite high. This subjects the head to forces of wear and abrasion. These conditions can result in selective damage, similar to erosion, to the permalloy pole tips or to the supporting materials surrounding the permalloy. At high operational speeds, a transducer which has been eroded will cause the magnetic recording media to flutter, or have varying and uncontrolled head-to- media separation. Even slight variations in head-to-media separation will cause substantial loss of signal which cannot be tolerated in sensitive or high-density read/write operations. An eroded head may also cause damage to magnetic recording media with which it comes in contact. These problems can be overcome by coating the transducer with hard nonwearing material, such as chromium, or by coating the head with material which has the same wear characteristics as permalloy.

Heads plated with nickel-phosphorus exhibit good wear resistance compatibility between the plated material and the permalloy pole tips. The nickel-phosphorus is deposited by electrodeposition, for example, as describ...