| 摘要 |
PURPOSE:To improve the melt nitrided surface state of an Al material and provide superior wear resistance by repeatedly subjecting the material to heat melting and slow cooling in a mixed gas atmosphere of an inert gas and ammonia under different arc conditions. CONSTITUTION:Al or its alloy is melted by heating with arc heat for a predetermined time in a mixed gas atmosphere formed by adding 0.10-20% gaseous ammonia to an inert gas such as Ar, He or nitrogen, and the molten Al material is slowly cooled. While changing the arc condition within 25-85% of the arc current value in the melt nitriding, melting is repeated 1-5 times in the same gas atmosphere or a nitrogen-free gas atmosphere. By this method the uneven state of a melt nitrided surface is reduced to give a fine surface state. |
