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Browse Prior Art Database

Head Wear Sensors

IP.com Disclosure Number: IPCOM000051855D
Original Publication Date: 1981-Mar-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Hahn, FW: AUTHOR [+2]

Abstract

Thin metallic films of a nickel-iron material can be used to measure wear rates and temperature of a magnetic head, for instance, at the wearing interface. Vacuum deposition and photolithographic techniques can be used to fabricate and pattern these sensors and their associated leads. The small dimensions of the films permit making wear samples with the sensor sandwiched between two pieces of the actual test material. Calibration curves of subsurface depth versus resistance and of temperature versus resistance are readily established.

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Head Wear Sensors

Thin metallic films of a nickel-iron material can be used to measure wear rates and temperature of a magnetic head, for instance, at the wearing interface. Vacuum deposition and photolithographic techniques can be used to fabricate and pattern these sensors and their associated leads. The small dimensions of the films permit making wear samples with the sensor sandwiched between two pieces of the actual test material. Calibration curves of subsurface depth versus resistance and of temperature versus resistance are readily established.

As shown in the figure, a vertically disposed wear sensor was constructed such that the sensor element is sandwiched between two pieces of the material for which the wear and temperature data is to be obtained. For instance, in a magnetic head, the sensor element could be a nickel-iron film sandwiched between two insulator films of aluminum oxide, for instance, bonded by epoxy to the ferrite head material. The contoured air bearing surface is formed by a lapping process, with the resistance of the sensor element being monitored during the lapping process. The lapping process is stopped when a preselected resistance is attained. After this, the sensor element can be continually monitored during a wear test operation. The resistance of the sensor element determines the amount of wear that is taking place when the wearing medium, such as a magnetic tape, is drawn over the test medium, such as a head material.

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