TY - JOUR
T1 - Oxide coating containing apatite formed on Ti-25Nb-25Ta alloy treated by Two-Step Plasma Electrolytic Oxidation
AU - Pereira, Bruno Leandro
AU - Beilner, Gregory
AU - Lepienski, Carlos Maurício
AU - Szameitat, Erico Saito
AU - Chee, Bor Shin
AU - Kuromoto, Neide Kazue
AU - dos Santos, Leonardo Luis
AU - Mazzaro, Irineu
AU - Claro, Ana Paula Rosifini Alves
AU - Nugent, Michael J.D.
N1 - Publisher Copyright:
© 2019 Elsevier B.V.
PY - 2020/1/25
Y1 - 2020/1/25
N2 - Hydroxyapatite (HA) is a bioactive calcium phosphate capable of enhancing the implant/bone connection improving osteoconductivity and osseointegration process. However, the HA presents mechanical properties limiting its application. A good way to resolve this limitation is to combine the excellent biological properties of HA with materials with suitable mechanical behavior, like Ti-25Nb-25Ta alloy. The Ti-25Nb-25Ta alloy is composted by non-toxic and corrosion-resistant elements, presenting good biological compatibility. In this work, Plasma Electrolytic Oxidation (PEO) (using direct current-DC) was applied in conventional mode and Two-Step PEO aiming to produce a porous coating containing HA. It was not possible to produce a satisfactory coating applying conventional PEO due to successive spalling during the oxidation process. Adding a pretreatment to the conventional PEO changed the process to Two-Step PEO allowing to form a porous coating containing HA. The pretreatment was made by PEO using phosphoric electrolyte to produce a pre-coating. After that, the pre-coating was re-oxidized with calcium/phosphorus electrolyte. The Two-Step oxidized surface presented well-known good characteristics to applications in osseous implant devices such as porous formation, roughness in the micrometrical range, surface containing calcium and phosphorus, bioactive crystalline titanium oxide, and well-adhered HA formation. However, the coating morphology and chemical composition of pre-coating and Two-Step oxidized surfaces were not uniform. The non-uniformity of the Two-Step oxidized surface follows a similar non-uniformity pattern of the pre-coating surface. Two distinct morphologies were identified on the Two-Step oxidized surface: a “velvety morphology” with HA formation and a highly porous morphology. Regarding the Ti-25Nb-25Ta alloy, the Two-Step oxidation produced an adhered coating with porous apatite distribution interspersed with calcium-rich porous oxide.
AB - Hydroxyapatite (HA) is a bioactive calcium phosphate capable of enhancing the implant/bone connection improving osteoconductivity and osseointegration process. However, the HA presents mechanical properties limiting its application. A good way to resolve this limitation is to combine the excellent biological properties of HA with materials with suitable mechanical behavior, like Ti-25Nb-25Ta alloy. The Ti-25Nb-25Ta alloy is composted by non-toxic and corrosion-resistant elements, presenting good biological compatibility. In this work, Plasma Electrolytic Oxidation (PEO) (using direct current-DC) was applied in conventional mode and Two-Step PEO aiming to produce a porous coating containing HA. It was not possible to produce a satisfactory coating applying conventional PEO due to successive spalling during the oxidation process. Adding a pretreatment to the conventional PEO changed the process to Two-Step PEO allowing to form a porous coating containing HA. The pretreatment was made by PEO using phosphoric electrolyte to produce a pre-coating. After that, the pre-coating was re-oxidized with calcium/phosphorus electrolyte. The Two-Step oxidized surface presented well-known good characteristics to applications in osseous implant devices such as porous formation, roughness in the micrometrical range, surface containing calcium and phosphorus, bioactive crystalline titanium oxide, and well-adhered HA formation. However, the coating morphology and chemical composition of pre-coating and Two-Step oxidized surfaces were not uniform. The non-uniformity of the Two-Step oxidized surface follows a similar non-uniformity pattern of the pre-coating surface. Two distinct morphologies were identified on the Two-Step oxidized surface: a “velvety morphology” with HA formation and a highly porous morphology. Regarding the Ti-25Nb-25Ta alloy, the Two-Step oxidation produced an adhered coating with porous apatite distribution interspersed with calcium-rich porous oxide.
KW - Hydroxyapatite
KW - Nanoscratch test
KW - Ti-25Nb-25Ta
KW - Two-Step PEO
KW - β-Titanium alloys
UR - http://www.scopus.com/inward/record.url?scp=85076159581&partnerID=8YFLogxK
U2 - 10.1016/j.surfcoat.2019.125224
DO - 10.1016/j.surfcoat.2019.125224
M3 - Article
AN - SCOPUS:85076159581
SN - 0257-8972
VL - 382
JO - Surface and Coatings Technology
JF - Surface and Coatings Technology
M1 - 125224
ER -