NATIONAL RT-46 NCK Audio Cassette Type I

NATIONAL RT-46
Brand New

Iron Oxide

Iron(III) oxide or ferric oxide is the inorganic
compound with the formula Fe2O3.
Iron (III) oxide was the most common
magnetic particle used in all types of magnetic
storage, magnetic tapes and recording media.
Cassette tapes are made of a polyester-type
plastic film with a magnetic coating.
The original magnetic material was based on
gamma ferric oxide (Fe2O3).
Inexpensive cassettes commonly are labeled
Low-noise, but typically are not optimized
for high frequency response. For this reason,
some low-grade IEC Type I tapes have been
marketed specifically as better suited for
voice or AM radio programs than for music
recording.
Simple voice recorders and earlier cassette
decks are designed to work with standard
ferric formulations. Newer tape decks usually
are built with switches and later detectors for
the different BIAS and equalization requirements
for higher grade tapes. The most common,
iron oxide tapes (defined by the IEC 60094
standard, as “Type I”) use 120 µs equalization.
In 1973, Pfizer produced a new pigment of iron
oxide, MO 2228, so a new generation of Ferric
tapes has emerged, a better quality one.
The quality normally is reflected in the price;
Type I cassettes generally are the cheapest.
In comparative terms of sale, the Ferro cassettes
occupy the first place.
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