| 摘要 |
PURPOSE:To obtain a magnetic tape with good durability, by forming a ferromagnetic layer on the surface of a tapelike base which moves along a cooling roll, etc., so that the partial pressure of oxygen is maximum and the ratio between the whole pressure of gas other than oxygen and a mean vapor-deposition speed is less than a specific value. CONSTITUTION:The inside of a vacuum tank 10 is partitioned by a partition 11 into a take-up room 12 and a vaporation room 13 to form mutually independent evacuation systems and on the tapelike base 2 which moves along a cylindrical can 1 as shown by an arrow, the magnetic layer is formed by emitting an electron beam 7 from an electron gun 6 to a vapor-deposition source 3 for Co-Ni, etc. In this case, the minimum angle of incidence of the vapor flow passed through the mask 4 is limited; when the part where the vapor is received is A, the center of the can 1 is 0, and the part that the vapor strikes at an angle close to a tangent is A, the mean vapor-desposition speed R (Angstrom /sec) depending upon the angle AOB and the moving speed V of the substrate 1 is calculated, and vapor deposition is carried out so that the relation when the partial pressure of oxygen is maximized and the partial pressure of gas other than oxygen is denoted as Pt is satisfied. In this case, Pa is pressure unit pascal. Thus, the long-life magnetic tape which is durable even when stored under various conditions. |
