580470.fig.003a
(a) Nitrided driving gears
580470.fig.003b
(b) Nitrided driven gears
580470.fig.003c
(c) Nitrided+TiN coated driving gears
580470.fig.003d
(d) Nitrided+TiN coated driven gears
Figure 3: The macrophotograph of tooth surface after running test.