窒素イオン注入したTi合金のトライボロジー特性

抄録

In order to investigate the mechanical properties of ion-implanted Ti alloy (Ti-6Al-4V), disk samples of Ti-6Al-4V were implanted with 200keV N₂⁺ ions at doses of 2.5×10¹⁶ to 5×10¹⁷ ions/cm². Tribological properties were evaluated with pin-on-disk tests. Bearing steel (SUJ2) balls 5mm in diameter were used as pins. Sliding conditions were as follows: load, 0.46N; speed, 0.04m/s; oil lubrication, SAE 7.5W-30.
Knoop hardness (load: 98mN) increased from Hk 356 to Hk 556 (dose: 5×10¹⁷ions/cm²) with ion dosage. The coefficient of friction of N₂⁺ ion-implanted Ti-6Al-4V disks ranged from 0.1 to 0.2, values that were lower than 0.6 obtained for an unimplanted disk. N₂⁺ ion implantation reduced wear on the pins as well as on the Ti-6Al-4V disks. The seizure load of N₂⁺ ion-implanted disks increased with ion dosage.