Sputtered WS2 films can be modified by adding some amount of hetero-elements to overcome the porous columnar microstructure and thereby to enhance the wear resistance. However, the recession of tribological properties of WS2-hetero-element composite films in low earth orbit environment would be a potential danger because most hetero-elements succumbed to oxidation by atomic oxygen. Herein, by altering deposition argon pressure to adjust the plasmas bombard function on growing WS2 film, the characteristic porous microstructure disappeared. At the optimization condition, the sputtered WS2 film exhibited a dense microstructure, high ratio of S to W, and thereby much better wear-resistance. However, the excessive bombardment would result in the prominent loss of S atoms in WS2 film and the deterioration of tribological properties. (C) 2018 Elsevier B.V. All rights reserved.