Tdk Corporation

Jun-ichi Satoh

Keiji Koga

Kenji Yokoyama

Yasumichi Tokuoka

Akinori Nisizawa

Tadashi Suzuki

Satoshi Maruyama

Tsuyoshi Iijima

Akinori Nishizawa

In a lithium secondary battery comprising positive and negative electrodes each comprising at least an active material capable of occluding and releasing lithium ions, a binder and a current collector, and an electrolytic solution, the active material in the positive and/or negative electrode has been made conductive by coating its surface with a conductive agent and a binder, and affixed to the surface of the collector by a dry process. The lithium secondary battery is given a higher energy density and a higher output density and will find a wider range of application.

Lithium secondary battery

When a magnetic disc is fabricated by forming on a rigid substrate a film of a magnetic coating material containing magnetic fine particles and a binder, and orienting and curing the film, the film is formed while a magnetic field is applied thereto, said magnetic field being larger in the strength on the inner side than on the outer side of said rigid substrate, thereby making it possible to form a magnetic layer that is uniform in thickness, or is thicker on the inner side and thinner on the outer side. This makes it possible to provide a coated type of magnetic disc in which there is a limited difference in the reproduction output and overwriting properties between the inner and outer sites.

Magnetic disc

A magnetic disk suitable for high density recording and reproduction of information wherein said disk is a coating type disk comprising a rigid substrate having a magnetic layer coated thereon from a magnetic coating composition of ferromagnetic submicron particles in a binder, wherein the substrate has a surface roughness Ra of up to 0.007 .mu.m, the magnetic layer has a thickness of up to 0.5 .mu.m, a surface roughness Ra of up to 0.005 .mu.m, and a porosity of 4 to 45%.

Magnetic disk

Information is magnetically recorded in and reproduced from a magnetic disk using a flying magnetic head. The disk is a coating type disk comprising a rigid substrate having a magnetic layer coated thereont from a magnetic coating composition of ferromagnetic submicron particles in a binder. High density recording is possible when the substrate has a surface roughness Ra of up to 0.007 .mu.m, the magnetic layer has a thickness of up to 0.5 .mu.m, a surface roughness Ra of up to 0.005 .mu.m, and a porosity of 4 to 45%.

Method for making a magnetic disk

Information is magnetically recorded in and reproduced from a magnetic disk using a flying magnetic head. The disk is a coating type disk comprising a rigid substrate having a magnetic layer coated thereon from a magnetic coating composition of ferromagnetic submicron particles in a binder. High density recording is possible when the magnetic layer having a coercive force of at least 1100 Oe and a thickness of up to 0.5 .mu.m is combined with the flying magnetic head whose gap adjoining portion is made of a soft magnetic material having a saturation magnetic flux density of at least 0.7 T.

Growing community of inventors

Saku, Japan

Jun-ichi Satoh