National Institute for Materials Science

Masahiro Tosa

Akira Kasahara

Masahiro Goto

Michiko Sasaki

Toyohiro Chikyo

Kazuhiro Yoshihara

Tetsuo Oishi

ZnO sputtering is performed while a rolling body is housed in a basket made of a metal wire and is rotated. By setting a ratio of a mesh size of the basket to a diameter of the rolling body in a range of 40 to 95%, fine and uniform ZnO coating can be formed on a surface of the rolling body. By using the rolling body with ZnO coating prepared in this manner in a bearing which is rotated at high speed in a high-load state, a friction coefficient can significantly be lowered in comparison with a case of no coating.

ZnO coating method for rolling body, rolling body with ZnO coating, and bearing incorporating same

Low friction coating of the present invention includes a boron-doped zinc oxide thin film, wherein piezoelectric polarization in a vertical direction perpendicular to a film surface and a lateral direction horizontal to the film surface occurs and a magnitude of the piezoelectric polarization in the vertical direction is within 150 pm and a magnitude of the piezoelectric polarization in the lateral direction is within 100 pm at 90% or more of measurement points. This makes it possible to greatly decrease the friction in a nanometer order.

Low friction coating formed of boron-doped zinc oxide thin film and micromachine

Provided is a polymer nanowire which contains nanoparticles so as to have new functionalities. A thin film is formed on a substrate and includes functional nanoparticles and polymers, and further includes a photosensitive pigment as required. The thin film is irradiated with a pulsed laser. This causes a polymer nanowire containing the functional nanoparticles to grow from a surface of the thin film.

Nanoparticle-containing polymer nanowire and method for producing the same

[Problem to be Solved] To provide a ZnO coating having low friction not only in a vacuum but in a liquid such as oil. [Solution] The low-friction ZnO coating, comprising (002) and (103) planes, and further comprising (100), (101), (102), and (104) planes in lower proportions than those of the (002) and (103) planes, has been prepared by sputtering using a zinc target in a sputter gas environment, wherein the sputter gas comprises an inert gas and oxygen gas, and the oxygen gas ratio is controlled. This coating has a specifically good low friction coefficient due to the piezoelectric effect, and this friction reduction mechanism is maintained even in oil such as n-hexadecane. Thus, this coating has been found to have excellent low-friction properties.

Low-friction ZnO coating and method for preparing the same

A copper oxide thin film mainly containing CuO is formed by a plasma film-forming process on a substrate for film formation. The friction coefficient of the copper oxide thin film can be controlled remarkably low.

Growing community of inventors

Ibaraki, Japan

Masahiro Tosa