Recording head has standard ferrite core directly coated with a thin film of a magnetic alloy composed of aluminum, iron, and silicon. Coated head has a lifespan from five to ten times longer than that of conventional heads and shows superior inductance characteristics and frequency response

Kern, J. D.

Vodicka, V. W.

English

NASA Technical Reports Server

September 1970	 Brief 70-10521 
NASA TECH BRIEF 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage commercial 
application. Tech Briefs are available on a subscription basis from the Clearinghouse for Federal Scientific and Technical 
Information, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Division, NASA, Code UT, Washington, D.C. 20546. 
I	 -. 
Extended-Life Magnetic Recording Heads 
An extended-life magnetic recording head has been 
developed in which a standard ferrite core is directly 
coated with a thin film of a magnetic alloy. The re-
cording head thus coated has a lifespan from five to 
ten times longer than that of conventional heads. At 
the same time, it shows superior inductance charac-
teristics and frequency response. 
In the coating process, the alloy, composed of 
aluminum, iron, and silicon, is deposited on the fer-
rite core by the technique of plasma arc sputtering. An 
electrically isolated ferrite substrate is mounted in a 
vacuum chamber about 1-1/2 inches from a target 
made from the bulk alloy. Both target and substrate 
are positioned midway between a filament and an 
anode that is maintained at a potential of 700 volts. 
During the sputtering process, the target is cooled by 
liquid from an external refrigeration unit. Initially, 
the chamber is evacuated to approximately 10- 6
 torr, 
the target is given a high negative potential, and a 
filament is heated to emit thermionic electrons. These 
electrons, streaming toward the anode, create a plasma 
between the target and substrate. 
At this point, the chamber pressure is raised to 10 
torr by the addition of high-purity argon gas. In the 
plasma, ionizing collisions occur between electrons 
and argon atoms, producing positively charged argon
ions. These ions bombard the target surface and dis-
lodge particles of the alloy, which are then deposited 
on the ferrite substrate. Using this system-, the rate 
of alloy deposition on the substrate ranges from 50 to 
300 A/mm. Total thickness of the alloy coating may 
be varied from 0.0015 to 0.004 in. 
The increased lifetime and improved properties of 
prototype alloy-coated magnetic recording heads has 
been measured in actual tests. 
Note: 
No additional documentation is available. Specific 
questions, however, may be directed to: 
Technology Utilization Officer 
Goddard Space Flight Center 
Code 207.1 
Greenbelt, Maryland 20771 
Reference: B70-10521 
Patent status: 
Inquiries about obtaining rights for the commercial 
use of this invention may be made to NASA, Code 
GP, Washington, D.C. 20546. 
Source: J. D. Kern and V. W. Vodicka of

Applied Magnetics Corp.
under contract to

Goddard Space Flight Center

(GSC- 10097) 
Category 01 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights.
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Extended-life magnetic recording heads

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