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20XV International Symposium on Self-Propagating High-Temperature Synthesis
STRUCTURE AND PROPERTIES OF ANTIBACTERIAL YET BIOCOMPATIBLE Ag-DOPED MULTICOMPONENT COATINGS OBTAINED BY PULSED ELECTROSPARK DEPOSITION USING SHS-ELECTRODES
E. I. Zamulaeva*", A. Yu. Potanin", A. N. Sheveyko", N. A. Gloushankovafi, N. V. Shvindina", S. G. Ignatovc, E. A. Levashov", and D. V. Shtansky"
aNational University of Science and Technology MISIS, Moscow, 119049 Russia bN. N. Blokhin Medical Research Center of Oncology of Ministry of Health, Moscow, 115478 Russia
cState Research Center for Applied Microbiology and Biotechnology, Obolensk, 142279 Russia *e-mail: zamulaeva@gmail.com
DOI: 10.24411/9999-0014A-2019-10202
Bone and joint degenerative and inflammatory problems affect millions of people worldwide, and the development of antibacterial yet biocompatible surfaces is a challenge that the biological community has been facing for many years, but the "materials of dream" have not been developed yet. Although the bulk properties of metallic materials in healthcare applications have been more or less optimized, the poor interfacial bonding between their surface and the surrounding tissue, as well as the occurrence of implant-related microbial infections remains a serious problem in reconstructive surgery. Surface engineering is an effective tool to impart desirable chemical, biological, and mechanical characteristics to the surface without compromising material bulk properties. For example, changing the chemical composition and surface roughness of metal implants can significantly improve their osteoconductive and osteoinductive characteristics. Another important task is imparting antibacterial characteristics to a surface in order to reduce the risk of microbial contamination when integrating the implant into living tissue. Self-propagating high-temperature synthesis (SHS) has become a "hot" and a rapidly developing topic in surface engineering. The most notable progress has been made in the field of SHS-produced targets and electrodes, which are widely used for deposition of various types of coatings. The aim of this work is to obtain antibacterial yet biocompatible coatings using pulsed electrospark deposition (PED). For this purpose new composite electrodes were fabricated from reaction mixtures Ti-C-20%Fe-10%Ca3(PO4)2-3.4%Mg-¥%Ag with different amount of antibacterial component (X = 0, 0.5, 1.0, 1.5. and 2.0 at % Ag) using SHS method. Figure 1 represents the microstructure of the synthesized electrodes.
During the pulsed electrospark deposition (PED) the electrodes with a high Ag content demonstrated an enhanced mass transfer (77%) but reduced material erosion. The PED coatings mainly consisted of spherical TiCx grains evenly distributed in the Ti-based matrix and oxide inclusions. The Ag particles were homogeneously distributed through the coating thickness and their amount increased when the Ag content in electrode was raised. The Ag-doped PED coatings are characterized by a relatively high hardness (> 11 GPa) and an increased surface roughness (Ra > 4.5 p,m). Regardless of the method of Ag introducing into the coatings (PED using Ag-containing electrode or Ag+ ion implantation into an Ag-free PED coating), the material with a small amount of Ag (< 1 at %) demonstrated a high antibacterial effect against both gram-positive S. aureus and gram-negative E. coli bacteria. Although small Ag concentrations had a negative effect on the adhesion of osteoblast cells, at the optimal Ag content (< 0.7 at %), the number of cells on the coating surfaces noticeably increased with time
iSHS 2019
Moscow, Russia
and were not statistically significantly different from that in controls after 3-5 days. Thus, the PED is a promising technology that allows for implementation of a relatively simple, cost-effective, and scalable approach to obtaining biocompatible yet bactericide materials with a rough surface in a single technological run.
Tie-
3/ flr1 Hi 1 MgO 1bT CaO
FeTiP ^f kM/M TiFe2
5 ¡xm
In
Ag(i-x)Mgx FeTiP
MgO
5 ¡m 5 ¡m 5 ¡¡m
(a) (b) (c) (d)
Fig. 1. Back-scattered electron SEM images of electrodes: X = 0 (a); 0.5 (b); 1 (c); and 2 (d) at %.
2
1. E.I. Zamulaeva, A.N. Sheveyko, A.Y. Potanin, I.Y. Zhitnyak, N.A. Gloushankova, I.V. Sukhorukova, N.V. Shvindina, S.G. Ignatovc, E.A. Levashov, D.V. Shtansky, Comparative investigation of antibacterial yet biocompatible Ag-doped multicomponent coatings obtained by pulsed electrospark deposition and its combination with ion implantation, Ceram. Int., 2018, vol. 44, pp. 3765-3774.
