| 摘要 |
PURPOSE:To improve the durability of the regulating board and the guide board by forming a boundary layer in which the content ratio of the metal element included in the primary coating layer uniformly decreases in the thickness-direction, which is provided between the primary coating layer of an essential metal element formed on the outer surface of the base material and the secondary layer of ceramic, both being the layers of a hard coating of the regulating board and the guide board. CONSTITUTION:A regulating board 16 and a guide board 17 that respectively regulates and guides a flexible rotary magnetic recording medium are provided in a manner that both are able to face to the recording medium as maintaining a specific interval between the medium and themselves. On the surfaces 18 and 19 of the regulating board 16 and/or the guide board 17 that face to the recording disc, a hard coating that consists of layers 47, 48, and 49 is formed. The layer 47 is made of a metal from groups III, IVa, Va, or VIa of the periodic table such as, for instance, Ti, and is formed directly on a base material of aluminum alloy or stainless steel. The layer 49 is made, for instance, of a ceramic that includes TiN. The boundary layer 48 includes Ti at such a ratio that decreases uniformly in its thickness direction from the layer 47 to the layer 49. In this way, crackings and peelings are prevented from occurring even if the environmental temperature drastically varies repeatedly.
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