| 摘要 |
<p>The invention relates to the plating of holes not exceeding 20 mm in diameter which are made in steel parts. A chemical process for plating in a gas phase, based on at least one additional element with a degree of electropositivity which is higher than that of iron, the surface of holes whose diameter is constant or variable over their length and does not exceed 20 mm, the holes being made in steel parts, this process employing a reductive or neutral atmosphere comprising at least hydrogen and halogenated vapour, with or without argon, at temperatures between 800 and 1050 DEG C and being characterised in that the said additional element constitutes all or part of a least one cylindrical core obtained beforehand by sintering, impregnated with an ammonium halide at the surface and arranged in the middle of the hole to be plated, over its whole length, in a well-centred manner, this cylindrical core having a diameter smaller than that of the hole to be plated. The invention applies specially to the chrome-plating of small holes in steel parts.</p> |
