Development of Metal Powder for Magnetic Recording

Abstract

The metal powder first used in the audio field (around 1980) had an Hc value of 1100 to 12000e, and a particle length of 0.5μm. Since audio systems have not changed, the situation is basically the same today, but improvements are constantly being made in electromagnetic conversion and coating characteristics. With the development of eightmillimeter video, the characteristics of metal powder changed significantly, with an Hc value of 15000e and a particle length as small as 0.3μm (around 1985). With the development of high-band eight-millimeter video around 1990, the degree of fineness was further improved, with an Hc value of 16000e and a particle length of 0.2μm being achieved.
Current metal powder has an He value of 1700 to 18000e and a particle length of 0.15μm. With the development of next-generation systems already underway, even greater degrees of fineness and higher He and σs values are being demanded. As time pass on, the realization of characteristics, such as 0.1μm in length and 20000e, will soon become an accomplished fact.