**Liang Hao 1,2, Hiroyuki Yoshida 3, Takaomi Itoi <sup>4</sup> and Yun Lu 4,\***


Academic Editors: Tony Hughes and Russel Varley Received: 1 February 2017; Accepted: 7 April 2017; Published: 10 April 2017

**Abstract:** We successfully applied mechanical coating technique to prepare Ti coatings on the substrates of steel balls and stainless steel balls. The prepared samples were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The weight increase of the ball substrates and the average thickness of Ti coatings were also monitored. The results show that continuous Ti coatings were prepared at different revolution speeds after different durations. Higher revolution speed can accelerate the formation of continuous Ti coatings. Substrate hardness also markedly affected the formation of Ti coatings. Specifically, the substance with lower surface hardness was more suitable as the substrate on which to prepare Ti coatings. The substrate material plays a key role in the formation of Ti coatings. Specifically, Ti coatings formed more easily on metal/alloy balls than ceramic balls. The above conclusion can also be applied to other metal or alloy coatings on metal/alloy and ceramic substrates.

**Keywords:** Ti coatings; steel balls; mechanical coating; process analysis
