To evaluate the friction properties of new lubrication systems, two types of ammonium-based ionic liquids (ILs), N,N-diethyl-N-methyl-N-(2-methoxyethyl) ammonium tetrafluoroborate ([DEME] [BF4]) and N,N-diethyl-N-methyl-N-(2-methoxyethyl) ammonium bis(trifluoromethanesulfonyl) imide aDEME][TFSI]), were investigated by resonance shear measurements (RSM) and reciprocating type tribotests between silica (glass) surfaces. RSM revealed that an IL layer of ca. 2 nm in thickness was maintained between the silica surfaces under an applied load of 0.40 mN similar to 1.2 mN. The relative intensity of the RMS signal indicated that the friction of the system was lower for [DEME] [BF4], 0.12, than that of [DEME] [TFSI], 0.18. On the other hand, the friction coefficients mu(k) obtained from the tribotests of [DEME] [BF4] were lower than that of [DEME] [TFSI] for sliding velocities in the range of 5.0 X 10(-4)m s(-1) to 3.0 x 10(-2) m s(-1) under applied loads of 196-980 mN. The friction coefficients obtained by the tribotest are discussed with reference to the RSM results.