Wear behavior of graphite(C) and molybdenum disulfide(MoS_2) in some regulated relative humidity was examined on a reciprocated sliding test against a single steel ball. These two solid lubricants were used singly or by mixture(C/MoS_2) in the form of powder layer or laser clad layer on the stainless steel substrate. Wear life of powder layers was affected by humidity. With C, MoS_2 and C/MoS_2 powder layers, wear life decreased with increasing humidity. Humidity change had also a marked effect on the life of the laser clad C/MoS_2 layer formed in argon, but provided no influence on the layer formed in air, since the latter layer was combined with the substrate, not by themselves, by a molybdenum oxide MoO_3.
