The Effect of Zirconia Coating by the Sol-Gel Method on the Morphology and Corrosion Resistance of Ti-6Al-4V Alloys After Different Surface Treatments

Abstract

Titanium and titanium alloys are widely used in biomedical applications due to their high mechanical strength, low density, and excellent biocompatibility. However, surface modifications are necessary to enhance corrosion resistance and improve biocompatibility for long-term use. In this study, zirconia (ZrO2) coatings were applied to Ti-6Al-4V alloy using the sol-gel method. Prior to coating, the surface preparation of the samples was carried out using different processes. The samples were divided into three groups based on surface treatments: grinding, polishing, and chemical etching. The morphological structure, coating thickness, and corrosion resistance of the sol-gel coatings were examined in detail. The characterization of the coatings was performed using surface roughness measurements, SEM-EDS, XRD, and three-electrode corrosion tests. Corrosion tests were conducted in a simulated body fluid at 37°C and pH 7.4, and the results were evaluated. As a result of the study, the highest coating thickness was measured at 3.3 µm for the sample prepared with 500-grit sandpaper, while the lowest thickness was 1.6 µm for the polished sample. XRD analysis revealed that the dominant phase in the coating was tetragonal ZrO2, indicating a crystallized structure. In corrosion tests, uncoated Ti-6Al-4V alloy exhibited the highest corrosion rate, whereas the lowest corrosion rate was observed in the 500-grit sanded and coated sample, with an 80% reduction in corrosion rate. The results demonstrated that surface preparation significantly affects coating thickness and corrosion resistance.

Keywords

• Ti-6Al-4V alloy
• Zirconia (ZrO2) coating
• Sol-gel method
• corrosion

Supporting Institution

TUBITAK

Ethical Statement

This study does not involve any experiments on human or animal subjects; therefore, ethical approval was not required. The authors declare that there is no conflict of interest.

Thanks

This study was supported by the TÜBİTAK 2209-B Industry-Oriented Research Projects Support Program.

Farklı Yüzey İşlemleri Sonrası Ti-6Al-4V Alaşımlarına Sol-Jel Yöntemi ile Zirkonya Kaplamanın Morfoloji ve Korozyon Direncine Etkisi

Abstract

Titanyum ve titanyum alaşımları, yüksek mekanik dayanımları, düşük yoğunlukları ve mükemmel biyouyumlulukları nedeniyle biyomedikal uygulamalarda yaygın olarak kullanılmaktadır. Ancak, uzun süreli kullanımlarda korozyon direncinin artırılması ve biyouyumluluğun iyileştirilmesi için yüzey modifikasyonları gerekmektedir. Bu çalışmada, Ti-6Al-4V alaşımı üzerine sol-jel yöntemi ile zirkonya (ZrO2) kaplamalar uygulanmıştır. Kaplama öncesinde numunelerin yüzey hazırlıkları farklı işlemlerle gerçekleştirilmiştir. Numuneler, yüzey işlemleri açısından zımparalama, parlatma ve kimyasal dağlama gruplarına ayrılmıştır. Sol-jel yöntemi ile elde edilen kaplamaların morfolojik yapısı, kaplama kalınlığı ve korozyon direnci detaylı olarak incelenmiştir. Kaplamaların karakterizasyonu yüzey pürüzlülük ölçümleri, SEM-EDS, XRD ve üç elektrotlu korozyon testleri kullanılarak gerçekleştirilmiştir. Korozyon testleri, yapay vücut sıvısı ortamında 37°C sıcaklık ve 7,4 pH değerinde gerçekleştirilmiş olup elde edilen sonuçlar değerlendirilmiştir. Çalışma sonucunda kaplama kalınlığı açısından en yüksek değer 3,3 µm ile 500 grit zımpara kullanılan numunede ölçülürken, en düşük değer 1,6 µm ile parlatılmış numunede elde edilmiştir. XRD analizleri, kaplamada baskın olarak tetragonal ZrO2 fazının bulunduğunu ve yapının kristalize olduğunu göstermiştir. Korozyon testlerinde, kaplanmamış Ti-6Al-4V alaşımı en yüksek korozyon hızına sahipken, en düşük korozyon hızı %80 azalma ile 500 grit zımparalanmış ve kaplanmış numunede gözlenmiştir. Sonuçlar, yüzey hazırlama işlemlerinin kaplama kalınlığı ve korozyon direnci üzerinde doğrudan etkili olduğunu göstermiştir.

Keywords

• Ti-6Al-4V alaşımı
• Zirkonya (ZrO2) kaplama
• Sol-jel yöntemi
• korozyon

Supporting Institution

Tübitak

Ethical Statement

Bu çalışma insan veya hayvan denekler üzerinde herhangi bir deney içermemektedir; dolayısıyla etik kurul onayı gerekmemektedir. Yazarlar, herhangi bir çıkar çatışması olmadığını beyan eder.

Thanks

Bu çalışma TÜBİTAK 2209-B Sanayiye Yönelik Araştırma Projeleri Destekleme Programı tarafından desteklenmiştir.

References

1. [1] Shokrani A, Dhokia V, Newman ST. Environmentally conscious machining of difficult-to-machine materials with regard to cutting fluids. International Journal of Machine Tools and Manufacture. 2012; 57: 83–101.
2. [2] Sivakumar K, Mathan Kumar P, Amarkarthik A, Jegadheeswaran S, Shanmugaprakash R. Empirical modeling of material removal rate and surface roughness of OHNS steel using Cu-TiB2Tool in EDM. Materials Today: Proceedings. 2021; 45: 2725–2729.
3. [3] Matoorian P, Sulaiman S, Ahmad MMHM. An experimental study for optimization of electrical discharge turning (EDT) process. Journal Of Materials Processing Technology. 2008; 204: 350–356.
4. [4] Pant P, Bharti PS. Electrical Discharge Machining (EDM) of nickel-based nimonic alloys: A review. Materials Today: Proceedings. 2020; 25: 765–772.
5. [5] Bishnoi P, Sahu M. Optimization of the Keyseat Design with Consideration of Effect of Stress Concentration on Different Materials. International Journal of Engineering Research & Technology. 2014; 3: 477–481.
6. [6] Kishor HP, Raghu T. Desıgn Analysıs of A Keyless Couplıng. International Journal of Recent Research in Civil and Mechanical Engineering. 2014; 1: 37–43.
7. [7] Verma V, Sajeevan R. Multi Process Parameter Optimization of Diesinking EDM on Titanium Alloy (Ti6Al4V) Using Taguchi Approach. Materials Today: Proceedings. 2015; 2: 2581–2587.
8. [8] Klocke F, Mohammadnejad M, Holsten M, Ehle L, Zeis M, Klink A. A Comparative Study of Polarity-related Effects in Single Discharge EDM of Titanium and Iron Alloys. Procedia CIRP. 2018; 68: 52–57.

9. [9] Bhaumik M, Maity K. Effect of different tool materials during EDM performance of titanium grade 6 alloy. Engineering Science and Technology, An International Journal. 2018; 21: 507–516.
10. [10] Singh NK, Singh Y, Sharma A, prasad R. Experimental investigation of flushing approaches on EDM machinability during machining of titanium alloy. Materials Today: Proceedings. 2021; 38: 139–145.
11. [11] Prakash J, Equbal MdI, Equbal A. Investigative study on dimensional accuracy of machined cavity formed during EDM of AISI 1035. Materials Today: Proceedings. 2021; 47: 3217–3220.
12. [12] Kumar P, Dewangan S, Pandey C. Analysis of surface integrity and dimensional accuracy in EDM of P91 steels. Materials Today: Proceedings. 2020; 33: 5378–5383.
13. [13] Sanchez JA, Lopez de Lacalle LN, Lamikiz A, Bravo U. Dimensional accuracy optimisation of multi-stage planetary EDM. International Journal of Machine Tools and Manufacture. 2002; 42: 1643–1648.
14. [14] Çakıroğlu R, Günay M. Comprehensive analysis of material removal rate, tool wear and surface roughness in electrical discharge turning of L2 tool steel. Journal Of Materials Research and Technology. 2020; 9: 7305–7317.
15. [15] Singh H, Shukla DK. Optimizing electric discharge machining parameters for tungsten-carbide utilizing thermo-mathematical modelling. International Journal of Thermal Sciences. 2012; 59: 161–175.
16. [16] Unses E, Çoğun C. Improvement of Electric Discharge Machining (EDM) Performance of Ti-6Al-4V Alloy with Added Graphite Powder to Dielectric. Strojniski Vestnik - Journal of Mechanical Engineering. 2015; 61.
17. [17] Azhiri RB, Bideskan AS, Javidpour F, Tekiyeh RM. Study on material removal rate, surface quality, and residual stress of AISI D2 tool steel in electrical discharge machining in presence of ultrasonic vibration effect. The International Journal of Advanced Manufacturing Technology. 2019; 101: 2849–2860.
18. [18] Koenig W. The Flow Fields in the Working Gap with Electro Discharge Machining. Annals Of The CIRP. 1977; 25: 71–75.
19. [19] Schumacher BM. About the Role of Debris in the Gap During Electrical Discharge Machining. CIRP Annals. 1990; 39: 197–199.
20. [20] Obara H, Abe M, Ohsumi T. Control of Wire Breakage during Wire EDM -1st Report: Monitoring of Gap Signals According to Discharged Location. International Journal of Electrical Machining. 1999; 4: 53–58.
21. [21] Cakiroglu R, Günay M. Elektro Erozyonla Tornalama Yöntemiyle İşlenen Soğuk İş Takım Çeliğinin Yorulma Ömrünün Tahmini. Politeknik Dergisi. 2021; 24: 495–502.