| 摘要 |
<p>A long-life member (rotor cylinder member, front cylinder cover member, rear cylinder cover member and the like) of an air motor of excellent abrasion resistance, impact resistance and thermal shock resistance the Vickers hardness of which is higher than that of a conventional member of this kind and uniform, obtained by forming on the surface of a vane-surrounding member which contacts a vane a nitrosulphurization layer having an average value of Vickers hardness of 800 to 1200 and a larger value of not larger than 100 out of a difference between this average value and a maximum value and a difference between the average value and a minimum value, by heating the mentioned contact surface to 450 to 580°C in a mixed gas atmosphere comprising 50 to 95 % hydrogen, 5 to 50 % nitrogen and 0.0l to 99 parts volume of hydrogen sulfide with respect to l00 parts volume of nitrogen, applying a DC voltage of 300 to 500V between the contact surface and a positive electrode provided in a vacuum chamber, and using a bright nitrogen diffusion method.</p> |
