| 摘要 |
PURPOSE:To obtain a video recording medium which excels in the traveling performance with high video characteristics and high durability, by using the ferromagnetic metallic powder consisting of the 1st and 2nd ferromagnetic powder with the specific surface area of the 1st ferromagnetic powder set more than the specific value and the specific surface area of the 2nd ferromagnetic powder set smaller than the 1st powder respectively. CONSTITUTION:It is needed that the specific surface area of the 1st ferromagnetic powder of small gtain size is set at >=40m<2>/gr (preferably at >=45m<2>/gr) and at the same time at <=100m<2>/gr (preferably at <=80m<2>/gr). If this specific surface area is too large, the characteristics are unstable. This increases the deterioration of characteristics of a magnetic tape. The 2nd ferromagnetic metallic powder has a specific surface area smaller than the 1st powder. The difference of the specific surface areas between the 1st and 2nd metallic powders should be larger than the value shown by a curve of a figure (a). If this difference is smaller than the value of said curve, the durability is unsatisfactory. At the same time, the mixture ratio between the 1st and 2nd metallic powders must be larger than the value shown by a curve of a fugure (b) in terms of the mixture ratio of the 1st powder. If this mixture ratio is smaller than the value of the curve, the video characteristics are unsatisfactory. |
