Titanium–Silicon on CoCr Alloy for Load-Bearing Implants Using Directed Energy Deposition-Based Additive Manufacturing

Abstract

Cobalt–chromium (CoCr) alloys offer outstanding wear resistance when compared to other biocompatible metallic materials and are extensively used in articulating surfaces of total hip and knee arthroplasty. However, CoCr alloys’ biocompatibility is known to be inferior to titanium (Ti). Wear- and corrosion-induced metal-ion release from CoCr alloys has been reported to cause cancer and negative physiological impacts. In this study, CoCr alloy was coated with commercially pure Ti (CpTi) and CpTi–Silicon (CoCrTi–Si) with the specific objective of reducing Co and Cr ion release during articulation, without degrading the excellent wear resistance of the CoCr alloy. Directed energy deposition (DED), a blown powder-based laser additive manufacturing technique, was utilized to process CpTi- and CpTi–Si-based coatings on Stellite 6B commercial CoCr alloy. Scanning electron microscopy (SEM), X-ray diffraction (XRD) analyses, and hardness testing found that refined carbides and titanium silicides increased the hardness from 321 ± 13 to 758 ± 48 HV0.5. Tribological studies determined a comparable wear rate between Stellite 6B alloy and CoCrTi–Si in DI water but a statistically significant reduction in Dulbecco’s Modified Eagle Medium (DMEM). The wear rates for Stellite 6B were 8.5 ± 0.8 × 10–5 and 12.9 ± 0.4 × 10–5 mm3/Nm in DI water and DMEM, respectively. While the wear rates for CoCrTi–Si were 9.1 ± 0.5 × 10–5 and 8.9 ± 0.8 × 10–5 mm3/Nm in DI water and DMEM, respectively. Contact resistance acquisition displayed the presence of a passive film formation during tribological testing. ICP-MS results for Stellite 6B and CoCrTi–Si concluded a reduction of Co ions release in DI water from 149.8 ± 66.7 to 17.5 ± 0.7 ppb and a reduction in Cr ions release from 66.7 ± 32.4 to 18.0 ± 0.5 ppb, respectively. In DMEM media, Co ion release for Stellite 6B and CoCrTi–Si reduced from 10.1 ± 1.4 to 4.1 ± 0.2 ppb and Cr ion release for Stellite 6B and CoCrTi–Si reduced from 8.7 ± 0.2 to 5.0 ± 0.7 ppb, respectively. The current study revealed a new mode of manufacturing for CoCr alloy-based load-bearing implants that can reduce toxic metal ions release due to wear- and corrosion-induced damages.

Design of High-Entropy Alloy Coating for Cavitation Erosion Resistance by Different Energy-Induced Dynamic Cyclic Behaviors

“…As shown in Figure B–D, these spherical particles were actually composed of more particles with a size of only 3–5 nm, and their composition was determined as Cr 2 O 3 by measuring the interplanar spacing ( d (110) ≈ 0.2496 nm, d (202) ≈ 0.2052 nm, and d (113) ≈ 0.2184 nm). It is well known that Cr is one of the most corrosion-resistant metal elements, and it is almost impossible to be corroded in deionized water with very weak aggressivity. , Therefore, it could be inferred that these Cr 2 O 3 nanoparticles were mainly derived from the oxidation of material surface by cavitation heat. However, due to the powerful hysteresis diffusion effect of high-entropy alloy, the oxidation rate was extremely slow, so only nanoscale oxides were formed.…”

“…It is well known that Cr is one of the most corrosion-resistant metal elements, and it is almost impossible to be corroded in deionized water with very weak aggressivity. 58,59 Therefore, it could be inferred that these Cr 2 O 3 nanoparticles were mainly derived from the oxidation of material surface by cavitation heat. However, due to the powerful hysteresis diffusion effect of high-entropy alloy, the oxidation rate was extremely slow, so only nanoscale oxides were formed.…”

Doğrudan Enerji Biriktirmesi ve Seçimli Lazer Ergitmesi Uygulamalarının Inconel 718 Mikroyapısında Yol Açtığı Değişimler

“…Biyomedikal, otomotiv ve hava-uzay gibi birçok uygulama alanı mevcuttur [3,4]. Eklemeli imalat teknikleri seçimli lazer [5] ve elektron ışını ergitmesi [6,7] gibi toz yataklı sistemlerin yanı sıra, tel-arkı eklemeli imalat [8,9] ve doğrudan enerji biriktirmesi [10,11] gibi yöntemleri de kapsamaktadır. Eklemeli imalat yöntemi kafes yapılar ve ince kanalların bulunduğu parçaların üretimi dışında geometrik olarak kompleks parçaların üretilmesi, topoloji optimizasyonu ile dizayn edilen parçaların üretilebilmesi ve işlemesi zor malzemelerin imalatına da olanak sağlar [5,12,13].…”

Niobium carbide reinforced‐Ti6Al4V composites via directed energy deposition

“…Its implementation has been shown to reduce part weight and allow for designs never before feasible with conventional methods 9,10 . The next stage of AM is to ease the manufacturing of bimetallic/multi‐material parts or apply coatings in a one‐step process, as has been seen with current novel work 11–15 . Adding high temperature, harder and wear‐resistant coatings while building a structural part will increase the part's service life.…”

“…9,10 The next stage of AM is to ease the manufacturing of bimetallic/multi-material parts or apply coatings in a one-step process, as has been seen with current novel work. [11][12][13][14][15] Adding high temperature, harder and wear-resistant coatings while building a structural part will increase the part's service life.…”