SONY FerriChrome | 1976/1978
Sony developes double layer Ferrichrome tape (thiner chrome coat lie on a top of gamma ferric pigment). Since SONY had exclusive right to chrome pigment in Japan. Maxell, TDK and FUJI decided to purse other possibilities to replace chrome pigment with cobalt dotted ferric. It took Japanese chemists to fix the cobalt ions to the outside crystalline structure (epitaxial) or within the structure (adsorptive Avilyn) to stabilize the pigment and get away from having to pay Sony for American oxide. As a result TDK develops AVILYN, Maxell developes EPITAXIAL and FUJI develops BERIDOX. Also TDK, Maxell and FUJI are not able to produce FerriChrome tapes.