Abstract
Oxidation behavior of NiTi alloy has been investigated under isothermal temperature by thermo gravimetric analysis (TGA), differential scanning calorimeter (DSC), X-ray diffraction (XRD) and scanning electron microscopy equipped with a dispersive X-ray (SEM-EDX) spectroscope systems. The Ni-45.16% Ti (composition in atomic percent) was exposed to air atmosphere, i.e., between 400˚C and 800˚C, for 1h. It was found that Ni-rich NiTi alloy exhibits different oxidation behaviour at temperatures above 400˚C in air atmosphere. The activation energy (estimated from Arrhenius plots) of oxidation reaction for NiTi alloy was determined to be 111,64 kj/mol. According to DSC measurements, the transformation temperature of alloy (Ms, Mf, As and Af) was increased and also R phase disappeared above 500˚C. X-ray diffraction patterns of the heat-treated specimens contain oxide peaks, mainly belonging to TiO2. X-ray analyses demonstrate that the amount of the TiO2 and Ni3Ti peaks expands with isothermal temperature while that of NiTi(B2), NiTi(B19) and Ni4Ti3 peaks decreases. In addition to the formal oxides were determined by means of SEM-EDX measurements and obtain oxides are TiO and TiO2
References
- Kök M., Yıldız K. 2014. Oxidation Parameters Determination of Cu–Al–Ni–Fe Shape-Memory Alloy at High Temperatures Appl. Phys. A., DOI 10.1007/s00339-014-8394-3.
- Kök M., Pirge G., Yıldırım A. 2013.Isothermal Oxidation Study on NiMnGa Ferromagnetic Shape Memory Alloy at 600–1000 ˚C., Appl. Surface Sci., 268, 136-140,.
- Bazochaharbaks, E., Surface Nitrating and Oxidation of Nitinol, Master Thesis, San Jose State University, 2011.
- Degeratu, S., Rotaru, P., Manolea G., Monolea H. Rotaru A., Thermal Characteristics of Ni-Ti SMA (Shape Memory Alloys) Actuators. J. Therm Anal Calorim., 97, 695-700, 2009.
- Morgan, N.B., Medikal Shape Memory Alloy Applications-the Market and its Products, Mater Sci. Eng., A378, 16-23, 2004.
- Thomson, S.A., An Overview of Nickel-Titanyum Alloys Used in Dentistry, Int. Endod J., 33, 297-310, 2000.
- Duering, T., Pelton, A., Stöckel, D., An Overview of Nitinol Medical Applications, Mater Sci Eng., A273-A275, 149-160, 1999.
- Lin, KL., Wu, SK., Oxidation Behavior of Ti50Ni40Cu10 Shape Memory Alloys in 700-1000˚C Air, Oxid. Met., 71, 187-200, 2009.
- Chu, CL., Wu, SK., Yen, YC., Oxidation Behavior of Equiatomic TiNi Alloy in High Temperature Air Environment, Mat. Sci. Eng., 216, 193-200, 1996.
- Firstov, GS., Vitchev, RG., Kumar, H., Blanpain, B., Van Humbeeck, J., Surface Oxidation of NiTi Shape Memory Alloys, Biomaterials, 23, 4863-4871, 2002.
- Dağdelen F. ve Ercan E. 2014. The Surface oxidation behavior of Ni-45.16%Ti Shape Memory Alloys at Different Temperatures Journal Thermal Anaysis Calorim, 115, 561-565,.
- Cesari E., Santamarta R., Pons J., Segui C. 1999. Ageing Effects in Ni-Ti Shape Memory Alloys, Dept. de Fisica, Universitat de Illes Balears, 443-452 Mallorca.
Abstract
NiTi alaşımının oksidasyon davranışı; thermogravimetrik analiz (TGA), diferansiyel taramalı kalorimetresi (DSC), X-ışını difraksiyonu (XRD) ve taramalı elektron mikroskobu enerji dağılımlı X-ışını spektrometresi (SEM-EDX) analizleri ile izotermal sıcaklıklarda araştırıldı. Ni-45.16% Ti (atomikçe) alaşımı 400-800 ˚C sıcaklıkları arasında 1 saat süresince hava atmosferine maruz bırakıldı. Hava atmosferindeki nikelce zengin NiTi alaşımı, 400˚C üzerindeki sıcaklıklarda farklı oksidasyon davranışı sergilediği görüldü. NiTi alaşımı için oksidasyon davranışının aktivasyon enerjisi (Arrhenius eğrisi kullanılarak) 111,64 kj/mol olarak hesaplandı. DSC ölçümlerine göre, alaşımın dönüşüm sıcaklıklarının (Ms, Mf, As and Af) arttığı ve 500˚C üzerindeki sıcaklıklarda R fazının kaybolduğu görüldü. Isıl işlem görmüş numunelerin X-ışını difraksiyon desenleri ile özellikle TiO2 oksit piklerinin olduğu görüldü. İzotermal sıcaklık ile TiO2 ve Ni3Ti piklerinin miktarlarının arttığını, böylece NiTi (B2), NiTi (B19) ve Ni4Ti3 piklerinin azaldığı X-ışını analizleri ile gözlendi. Ayrıca asıl oksitlerin SEM-EDX ölçümleri ile belirlenip TiO ve TiO2 olduğu gözlendi.
References
- Kök M., Yıldız K. 2014. Oxidation Parameters Determination of Cu–Al–Ni–Fe Shape-Memory Alloy at High Temperatures Appl. Phys. A., DOI 10.1007/s00339-014-8394-3.
- Kök M., Pirge G., Yıldırım A. 2013.Isothermal Oxidation Study on NiMnGa Ferromagnetic Shape Memory Alloy at 600–1000 ˚C., Appl. Surface Sci., 268, 136-140,.
- Bazochaharbaks, E., Surface Nitrating and Oxidation of Nitinol, Master Thesis, San Jose State University, 2011.
- Degeratu, S., Rotaru, P., Manolea G., Monolea H. Rotaru A., Thermal Characteristics of Ni-Ti SMA (Shape Memory Alloys) Actuators. J. Therm Anal Calorim., 97, 695-700, 2009.
- Morgan, N.B., Medikal Shape Memory Alloy Applications-the Market and its Products, Mater Sci. Eng., A378, 16-23, 2004.
- Thomson, S.A., An Overview of Nickel-Titanyum Alloys Used in Dentistry, Int. Endod J., 33, 297-310, 2000.
- Duering, T., Pelton, A., Stöckel, D., An Overview of Nitinol Medical Applications, Mater Sci Eng., A273-A275, 149-160, 1999.
- Lin, KL., Wu, SK., Oxidation Behavior of Ti50Ni40Cu10 Shape Memory Alloys in 700-1000˚C Air, Oxid. Met., 71, 187-200, 2009.
- Chu, CL., Wu, SK., Yen, YC., Oxidation Behavior of Equiatomic TiNi Alloy in High Temperature Air Environment, Mat. Sci. Eng., 216, 193-200, 1996.
- Firstov, GS., Vitchev, RG., Kumar, H., Blanpain, B., Van Humbeeck, J., Surface Oxidation of NiTi Shape Memory Alloys, Biomaterials, 23, 4863-4871, 2002.
- Dağdelen F. ve Ercan E. 2014. The Surface oxidation behavior of Ni-45.16%Ti Shape Memory Alloys at Different Temperatures Journal Thermal Anaysis Calorim, 115, 561-565,.
- Cesari E., Santamarta R., Pons J., Segui C. 1999. Ageing Effects in Ni-Ti Shape Memory Alloys, Dept. de Fisica, Universitat de Illes Balears, 443-452 Mallorca.
Details
| Primary Language | Turkish |
|---|---|
| Journal Section | Articles |
| Authors | |
| Publication Date | March 26, 2015 |
| Submission Date | March 26, 2015 |
| Published in Issue | Year 2015 Volume: 4 Issue: 1 |
