Pneumatic devices including surface coatings

A method of applying a coating to a pneumatic device comprising a piston member configured to move between a first position to a second position during actuation by a motor or engine, the method comprising depositing a surface coating on an exterior surface of the piston member of the pneumatic device, wherein the surface coating comprises an alloy layer comprising (i) molybdenum and (ii) phosphorous, boron, nitrogen or carbon and (iii) at least one element selected from the group consisting of nickel, tungsten, and tin, wherein the at least one element selected from the group consisting of nickel, tungsten, and tin is present in the alloy layer at 65% by weight or more based on the weight of the alloy layer, wherein the surface coating comprises a surface roughness Ra of less than or equal to 1 micron, and wherein the alloy layer comprises uniform and non-uniform grain sizes with an average grain size less than 2 microns.