Abstract
Purpose
Ion implantation with a high kinetic energy has advantages in controlling the size and distribution of coating materials, helping to overcome the limitations of conventional methods. This method resulted in uniformly and homogeneously distributed in a CoCr alloy even without a further annealing process. The study was to investigate the wear rate of UHMWPE on CoCr alloy for metal head by plasma immersion ion implantation (PIII) treatments.
MATERIALS AND METHODS
Commercially CoCr alloy (ISO 5832-12, ASTM F1537, alloy 1) were used as the substrate. PIII surface treatments were performed in a high-vacuum chamber with a radio frequency plasma source. We divided with two groups: PIII CoCr alloy, CoCr ally as control. Wear amount of UHMWPE (ISO 5834-2, ASTM F648, Type 1) on CoCr alloy specimens (three samples per group) was evaluated after 500,000 and 1,000,000 cycles using pin-on disk wear tester. After test, surface morthology was examined by SEM, and surface roughness was calculated in both groups.
RESULTS
The wear amount of UHMWPE was 0.00030g on PIII CoCr, and 0.00042g on control group (p=0.032). We observed statistical difference (p = 0.021) in surface roughness in the PIII CoCr and control group: 0.086 and 0.112, respectively. SEM images after 1,000,000 cycles shows the abrasion tracks on both groups.
CONCLUSIONS
PIII treatment could reduce the wear amount of UHMWPE for acetabular liner application. The surface roughness of PIII CoCr was lower than CoCr alloy.
