The properties of diamond-like carbon coatings used for artificial joints

Abstract

The paper presents the results of the tribological tests for materials used in elements of hip and knee endoprostheses. The tests were conducted for a Co-Cr-Mo alloy and the same material with a diamond-like coatings (DLC) coating produced by applying the plasma assisted chemical vapor deposition (PACVD) method. The materials to be tested were selected because of their good biocompatibility and high resistance to corrosion and sliding wear. The coating structure was determined by applying scanning electron and atomic force microscopes. The tribological characteristics were obtained with a T-17 tester operating in the pin-on-plate configuration under lubricated friction conditions. The friction pair consisted of a cobalt-based alloy plate, or alternatively, a cobalt-based alloy plate with a diamond-like carbon coating, and an ultra-high molecular weight polyethylene (UHMWPE) pin. The model lubricant used in the tests was Ringer's solution. The results indicated that the mechanisms of wear of the endoprosthesis elements were dependent mainly on the material used for the working surfaces in the friction joint. The wear resistance and friction coefficient of a cobalt-based alloy disc, or alternatively, a cobalt-based alloy disc with a diamond-like carbon coating, and an alumina ball were also determined by means of a T-01M tester during technically dry friction and lubrication in Ringer's solution. The comparative analysis confirmed different tribological effectiveness of the cobalt-based alloy and DLC coatings during friction. K e y w o r d s :

Diamond-like carbon coatings in biotribological applications

“…The superb mechanical and tribological characteristics, high surface smoothness and high biocompatibility make DLC a material highly recommended for biotribological applications [3,[7][8][9][10][11][12]. DLC coatings deposited on metal elements prove extremely useful in implants, because of their high resistance to wear and other surface properties, such as low surface energy and chemical passivity, which prevent blood coagulation and promote adhesion of osteoblasts, especially in corrosive environments [13][14][15][16][17].…”

“…Since endoprostheses are vulnerable to various kinds of tribological and corrosive damage, their longterm reliability depends primarily on the materials used for the friction pair [5,7,9,18]. The main parts of an artificial joint are a UHMWPE cup and a metal or ceramic ball (head).…”

The Structure and Characteristics of Tribological Systems with Diamond Like Carbon Coatings under Ionic Liquid Lubrication Conditions

“…The performance of machine components depends not only on the load-carrying capacity in the entire cross-section of the material, but mainly on the structure and characteristics of the surface layers [3,4]. For a coating to meet the required criteria, a suitable combination of physical, chemical and mechanical properties must be ensured, including high hardness, resistance to shear stress and bending, fracture toughness, resistance to friction wear and corrosion, and good adhesion on the substrate [3,[5][6][7][8][9][10]. Further investigations of the materials and lubricants are necessary to be able to address stringent requirements of the market.…”

“…While cooling a low-energy carbon ion beam in the argon environment, they produced hydrogen-free amorphous carbon films. This discovery was a huge breakthrough in the field of DLC coatings, and the recent years have seen substantial progress in DLC films-related research and application [3,[4][5][6][7][8][9][10][11]. Amorphous carbon consists of a mixture of sp 3 [15].…”

“…Owing to their unique properties, DLC coatings have a wide range of applications, for example, in electronics, for automobiles, in the textile industry, as medical devices and as wear resistant films for MEMS and NEMS devices [3,[5][6][7]11].…”