The effect of EO and steam sterilization on the mechanical and electrochemical properties of titanium Grade 4

Abstract

Currently, various modifications to surfaces are made more and more frequently in order to improve implants' haemocompatibility. The main criterion determining the applicability of the respective surface-modification method is obtaining a product featuring suitable functional properties. These properties depend to a great extent on the corrosion resistance in the environment of human blood. Subject-matter literature does not devote much attention to the sterilisation process for titanium and cpTi alloys with surface modifications. A problem that still remains unsolved is the selection of a proper test showing the full characteristics of their behaviour contact with a blood environment during the time that the implant is used. Therefore, the authors of this study made an attempt to evaluate the impact of medical sterilisation methods, i.e., the ethylene oxide anodic oxide and SiO2 layer, by means of the sol-gel method. The efficiency of the suggested technology for oxide layer application was evaluated on the basis of mechanical and electrochemical tests. Sterilisation in ethylene oxide and steam had a favourable influence on the electrochemical and mechanical properties of cpTi, irrespective of the method of surface preparation. In order to simulate real conditions, the tests were performed in artificial plasma at a temperature of T = 37 ± 1°C and pH = 7.0 ± 0.2. The results proved the diversification of electrochemical properties of the oxide layers, depending on the technological parameters of its application. The suggestion of proper variants of the surface modification with the application of electrochemical and chemical methods is of long-range importance and will contribute to the development of technological conditions with specific parameters for the creation of oxide layers on metallic implants made of cpTi. Keywords: cpTi (Grade 4), SiO 2 , TiO 2 , mechanical properties, electrochemical properties Vedno pogosteje se opravljajo razli~ne modifikacije povr{ine, da bi se izbolj{ala hemokompatibilnost vsadkov. Glavni kriterij, ki dolo~a uporabnost metode za modifikacijo povr{ine je, da proizvod poka`e primerne funkcionalne lastnosti. Te lastnosti so v veliki meri odvisne od korozijske odpornosti v~love{ki krvi. Obstoje~a literatura ne posve~a velike pozornosti postopku sterilizacije titana in cpTi zlitin z modificirano povr{ino. Problem, ki {e ni re{en, je izbira primernega preizkusa, ki bi pokazal vse zna~ilnosti o obna{anju stika s krvjo med uporabo vsadka. Zato so avtorji v tej {tudiji poizkusili oceniti vpliv medicinskih metod sterilizacije, kot je etilen oksid anodni oksid in SiO2 plast izdelano s pomo~jo metode sol-gel. Predlagana tehnologija uporabe oksidnega sloja je bila ocenjena z mehanskimi in elektrokemijskimi preizkusi. Sterilizacija v etilen oksidu in pari je imela ugodne vplive na elektrokemijske in mehanske lastnosti cpTi, ne glede na na~in priprave povr{ine. Za simulacijo realnih pogojev so bili preizkusi izvr{eni v umetni plazmi pri temperaturi T = 37 ± 1°C in pH = 7,0 ± 0,2. Dobljeni rezu...

Corrosion resistance of Ti6Al4V alloy coated with caprolactone-based biodegradable polymeric coatings

“…A common method of modifying the surface of titanium alloys is anodic oxidation. Interesting results were obtained by applying sol-gel and ALD coatings on titanium alloys [1,2,12,15,19]. However, despite numerous studies, the problem of harmful effects of metal biomaterial degradation products is still not fully resolved.…”

Potentiostatic, Potentiodynamic and Impedance Study of TiO2 Layers Deposited of 316 LVM Steel Used for Coronary Stents

“…All electrochemical test were carried out in the environment of artificial plasma with the chemical composition recommended by the standard [3,13,14] at the temperature T = 37±1°C, and pH = 7.0±0.2…”

“…R s -means resistance of the artificial plasma, R pore -is resistance of the electrolyte in the sublayer pores, and C pore -is capacity of the sublayer (porous, top), whereas R ct and CPe dl are resistance of charge transfer and capacity of the double layer. Application of two constant phase elements in the electric substitute circuit was beneficial for the quality of adjusting the curves determined experimentally [3].…”

“…There are many methods of surface modification of metal biomaterials. Those used most often include anodic passivation, the sol-gel method or PVD [1][2][3][4]. These modifications of surface of metal biomaterials by way of application of surface layers, resulting improvement of their physical and chemical properties in various degrees.…”

Physicochemical properties of a Ti67 alloy after EO and steam sterilization

“…2 Chemical methods include primarily etching and passivation, which result in the formation of a thin (<10 nm) oxide layer composed mostly of TiO 2 and oxides of the alloying elements, as well as impurities from chemical reagents. [3][4][5][6] Repeatable layers with a fully controlled thickness, microstructure and chemical composition are obtained with high-temperature treatments, immersion in H 2 O 2 , alkaline etching, electropolishing, anodic oxidation and vacuum treatments. However, the method for increasing the haemocompatibility of titanium and titanium-alloy surfaces, which is increasingly often applied, involves using the sol-gel technique to produce thin oxide coatings based on Si.…”