Carbide-derived carbon (CDC) coatings with dimple (CDC@GSiC coating) and loosely dispersive particles structures (CDC@RBSiC coating) were prepared on two kinds of SiC substrates by using chlorination at 1,000 A degrees C in a 5 vol.% Cl-2-Ar gas. Microstructural effect makes the two CDC coatings exhibit different frictional behavior in ambient pressure and in vacuum. For the CDC@RBSiC coating, the friction coefficient was from 0.08 to 0.12 at ambient pressure and is sensitive to evacuation from ambient pressure to 10(3) Pa while it was as high as 0.42 up to a pressure of 10(-4) Pa. Progressive evacuation does not vary the friction coefficient of the CDC@GSiC coating up to 10(-3) Pa. The wear of the CDC@GSiC coating was low with a maximum depth of 8 mu m and much lower than that of the CDC@RBSiC coating (70 mu m). The dimples on the surface and pores in the CDC@GSiC coating are reservoirs for ion liquid (IL), and the IL impregnated CDC@GSiC coating shows very low friction and wear at ambient pressure and in vacuum.