CoCrMo alloys have been used for biomedical implants for a number of years. One of the important parameters which influences durability of the coating and thus whole implant are parameters of surface texture, namely Ra and Rt, which are determined by standards ISO 7206-2:2011 and ISO 7207-2:2011. Three duplex surface systems were applied to improve mechanical properties. The combination of plasma nitriding and subsequent deposited thin films of the nACo 3 ®, DLC and ZrN were used as a duplex treatment. Plasma nitriding was implemented under these conditions: duration time 10 hours, the ratio of gases H 2 :N 2 =3:1, process temperature 450 °C, 500 °C and 550 °C. The surface texture parameters were measured on the polished surface of the CoCrMo alloy at first, then on the polished surface after plasma nitridation process and finally on the polished surface of deposited coating. It has been demonstrated that deposition of the selected coatings on the nitride surface influences the surface texture parameters Ra and Rt.
Texture of the surface is very important in process reproduction of the components. Not only in engineering area, but also in other industrial sectors, the assessment of the surface texture ranks among basic techniques of the determining the surface properties of the component. Pretreatment of the surface can reduce running costs in the case of coating on the tools. The paper describes the changes of the surface textures of the HS6-5-2-5 steel CSN EN ISO 4957 with different technological treatments of the substrates, coating and subsequently polishing of the coating. Substrate was sandblasted (wet) and polished before coating. Coating nACo® was applied by PVD method and surface of the coating specimens was subsequently polished by µLap method. Surface textures together with properties of the coating are decisive factors for their lifetime and durability of the cutting tools. The qualitative assessment of the changes surface texture was carried out by the 3D topography measurement of the surface by using Talysurf CCI Lite. TalyMap software was used for evaluation of the changes surface texture. For evaluation of the surface were used parameters: Sa -arithmetic mean deviation of the surface [μm], Sdq -root mean square slope of the surface [-] and Rk -core roughness depth [μm]. The results in the paper demonstrate positive effect of the polishing on texture coating on the tools.
Hydroxyapatite (HA) is widely applied as bone graft material due to its osteoconductive potential and well-established biocompatibility. The high osteoconductive potential of the HA coating provides a potential structure for use as bone substitute in orthopedic, oral, and cranio-maxillofacial reconstructive surgery, and as dento-alveolar implants. The aim of this work is to present hydroxyapatite coatings which were prepared on CoCrMo as-cast alloy by electrochemical deposition technology in the mixed solution Ca(NO 3 ) 2 ·4H 2 O and NH 4 H 2 PO 4 . CoCrMo alloy complies with the ISO 5832-4 standard and is widely used in the manufacturing of orthopedic implants because of its high strength, good corrosion resistance and excellent biocompatibility properties. HA coating is used to ensure sufficient bioactivity, but application of hydroxyapatite in orthopedic implants suffers from its low fracture toughness and poor wear resistance. Carbon nanotube (CNT), with its high stiffness and mechanical strength, is an attractive reinforcement for HA to surmount these issues.
The aim of the paper is analyse changes of the surface texture during pre-treatment, PVD coating and post-treatment. Generally, the effect of the production technology is often discussed with well-known parameters such as material, geometry of tools, coating methods and conditions. Effect treatment of the substrate or tools manufacturing are mostly ignored. Pre-treatment, coating and post-treatment obviously change surface texture. Quality of surface or surface texture together with properties of the surface layer have a significant effect of lifetime and reliability of operation component in practice. Surface texture effect running accuracy components, noise and running in period, friction loss, heat transfer, fatigue strength, resistance against wear and corrosion. The experiment was performed on ASP2052® tool steels during coating by PVD (Physical Vapour Deposition). The surface of the substrate was wet and dry sandblasted. Treated surface of experimental samples were coating of TiN. After coating surface of the samples was polished by and wet sandblasted to achieve glossy finished. The results of the paper show effect various type of the treatment on surface texture before and after PVD coating. Measurement of the surface texture shows progression of the parameters surface textures.
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