At about the same time, chromium dioxide (CrO 2) was introduced by DuPont and BASF and then coatings using magnetite (Fe 3 O 4) such as TDK's Audua were produced in an attempt to approach or exceed the sound quality of vinyl records.
At about the same time, chromium dioxide (CrO 2) tape, later designated Type II, was introduced by DuPont, the inventor of the particle, and BASF, the inventor and longtime manufacturer of magnetic recording tape. Next, coatings using magnetite (Fe 3 O 4) such as TDK's Audua were produced in an attempt to approach or exceed the sound quality of vinyl records.