Laser processing of in situ TiN/Ti composite coating on titanium.
Laser remelting of commercially pure titanium (CP-Ti) surface was done in a nitrogen rich inert atmosphere to form in situ TiN/Ti composite coating. Laser surface remelting was performed at two different laser powers of 425 W and 475 W. At each power, samples were fabricated with one or two laser scans. The resultant material was a nitride rich in situ coating that was created on the surface. The cross sections revealed a graded microstructure. There was presence of nitride rich dendrites dispersed in α-Ti matrix at the uppermost region. The structure gradually changed with lesser dendrites and more heat affected α-Ti phase maintaining a smooth interface. With increasing laser power, the dendrites appeared to be larger in size. Samples with two laser scans showed discontinuous dendrites and more α-Ti phase as compared to the samples with one laser scan. The resultant composite of TiN along with Ti2N in α-Ti showed substantially higher hardness and wear resistance than the untreated CP-Ti substrate. Coefficient of friction was also found to reduce due to surface nitridation. Leaching of Ti(4+) ions during wear test in DI water medium was found to reduce due to laser surface nitriding.
W. M. Keck Biomedical Materials Research Laboratory School of Mechanical and Materials Engineering Washington State University Pullman, WA 99164-2920, USA.
Himanshu
H
Sahasrabudhe
W. M. Keck Biomedical Materials Research Laboratory School of Mechanical and Materials Engineering Washington State University Pullman, WA 99164-2920, USA.
Julie
J
Soderlind
W. M. Keck Biomedical Materials Research Laboratory School of Mechanical and Materials Engineering Washington State University Pullman, WA 99164-2920, USA. Electronic address: amitband@wsu.edu.
Amit
A
Bandyopadhyay
D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D007834:Lasers; D008422:Materials Testing; D055595:Mechanical Phenomena; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*; D014867:Water
D020099:Coated Materials, Biocompatible; D014867:Water; C041500:titanium nitride; D014025:Titanium
Hard coatings; Laser processing; Surface modification; Ti nitride; Wear resistance