Low friction ZnO coating and manufacturing method thereof

To provide a ZnO coating of low friction, even in a liquid such as oil as well as in vacuum. By sputtering using by controlling the oxygen gas ratio of zinc target in a sputtering gas environment with inert gases as A sputtering gas (002) and (103) with including a surface (100), (101 ), (102) and (104) the plane including the (002) and (103) at a ratio smaller than surface, to produce a low-friction ZnO coating. With this coating has a specifically good low friction coefficient by the piezoelectric effect, even in oil, such as n- hexadecane The friction reduction mechanism is maintained, it was found to have excellent low friction characteristics. .BACKGROUND