**2. Experimental**

Okasaki [1] evaluated the properties of metallic biomaterials with regard to the effect of friction on anodic polarization. He observed that corrosion was accelerated in the frictional environment with respect to static conditions. This effect was due to the formation of anodic

Metallic particles released from the corrosion process may move passively, through tissue and/or circulatory system or can be transported in an active way when metabolized by macrophages [2]. In either case, this mass transport may lead to debris accumulation in surrounding tissues or even remote sites where they can participate in undesirable biological reactions,

Interaction between metallic implants and the human body can be affected by numerous factors such as the structure of the metal surface, its mechanical properties, size, and shape. When in contact with the body tissues after implantation, metallic devices affect the intensity of stresses to which the whole human body is subjected as well the implant itself. Wear and corrosion processes are additional effects arising from the interaction between metallic bio-

The orthopaedic implants are projected and manufactured so that when used under the conditions and for the purposes designed, without compromising the clinical condition or the safety of patients. Any risks that may be associated with the implants use are acceptable when

The alloy described in part 1 of ISO 5832 [4] (ASTM F138/ASTM F139) is an austenitic stainless steel. It is one of the metallic materials most used in Brazil for manufacturing implants, because of its suitable mechanical strength, reasonable corrosion resistance, and low cost [5–8]. Stainless steel implantable medical devices are used as permanent or temporary implants to help bone healing. The laser texturing process is used to modify the biomaterial surface

The microscale abrasion test (or ball-cratering wear test) is a practical method to analyze the wear resistance of materials [8–11]. The ball-cratering wear test has gained large acceptance at universities and research centers and is widely used in studies focusing on the abrasive wear behavior of different materials [12–16]. **Figure 1** presents a schematic diagram of the principle of this wear test, where a rotating ball is forced against the specimen being tested and an

**Figure 1.** Schematic representation of the operating principle of ball-cratering wear test.

areas in the stressed regions under friction whereas its periphery is cathodic.

compromising biomaterial's biocompatibility.

materials and the body tissues [3].

66 Lubrication - Tribology, Lubricants and Additives

roughness and hardness.

compared to benefits for the patients [2, 3].
