Surface characterizations of laser modified biomedical grade NiTi shape memory alloys.
Laser processing of shape memory alloys (SMAs) promises to enable the multifunctional capabilities needed for medical device applications. Prior to clinical implementation, the surface characterisation of laser processed SMA is essential in order to understand any adverse biological interaction that may occur. The current study systematically investigated two Ni-49.8 at.% Ti SMA laser processed surface finishes, including as-processed and polished, while comparing them to a chemically etched parent material. Spectrographic characterisation of the surface included; X-ray photoelectron spectroscopy (XPS), auger electron spectroscopy (AES), and Raman spectroscopy. Corrosion performance and Ni ion release were also assessed using potentiodynamic cyclic polarization testing and inductively coupled plasma optical emission spectroscopy (ICP-OES), respectively. Results showed that surface defects, including increased roughness, crystallinity and presence of volatile oxide species, overshadowed any possible performance improvements from an increased Ti/Ni ratio or inclusion dissolution imparted by laser processing. However, post-laser process mechanical polishing was shown to remove these defects and restore the performance, making it comparable to chemically etched NiTi material.
Centre for Advanced Materials Joining (CAMJ), University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada; Centre for Bioengineering and Biotechnology (CBB), University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada.
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Pequegnat
Centre for Advanced Materials Joining (CAMJ), University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada; Centre for Bioengineering and Biotechnology (CBB), University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada. Electronic address: a2michae@uwaterloo.ca.
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Michael
Centre for Advanced Materials Joining (CAMJ), University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada; Centre for Bioengineering and Biotechnology (CBB), University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada.
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Wang
Department of Materials Science and Engineering, University of Toronto, 184 College Street, Suite 140, Toronto, ON M5S 3E4, Canada.
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Lian
Centre for Advanced Materials Joining (CAMJ), University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada; Centre for Bioengineering and Biotechnology (CBB), University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada.
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Zhou
Department of Materials Science and Engineering, University of Toronto, 184 College Street, Suite 140, Toronto, ON M5S 3E4, Canada; Smarter Alloys, Inc., MaRS Centre, South Tower, 101 College Street, Suite 200, Toronto, ON M5G 1L7, Canada.
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Khan
D000497:Alloys / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D003343:Corrosion; D007477:Ions; D007834:Lasers; D009532:Nickel / Q000737:chemistry*; D056951:Photoelectron Spectroscopy; D013059:Spectrum Analysis, Raman; D013499:Surface Properties; D013696:Temperature; D014025:Titanium / Q000737:chemistry*
D000497:Alloys; D007477:Ions; C040654:titanium nickelide; D009532:Nickel; D014025:Titanium
Corrosion performance; Laser processing; Ni ion release; NiTi; Shape memory alloy (SMA); Surface characterisation