Laser pulse structure dependent texture of FEL synthesized TiN<sub><i>x</i></sub>coatings

Höche, Daniel; Shinn, Michelle D.; Kaspar, Jörg; Rapin, Gerd; Schaaf, Peter

doi:10.1088/0022-3727/40/3/019

Cited by 23 publications

(26 citation statements)

References 24 publications

(28 reference statements)

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“…As expected, the coating thickness t -measured by cross section SEM [11] -decreases with increasing scan velocity.…”

Section: 1supporting

confidence: 80%

“…The samples were analyzed by a range of methods [11], while the focus here will be on the results from X-ray diffraction (XRD). XRD was performed on a Bruker AXS D8 Advance diffractometer equipped with a Cu K α long-finefocus tube.…”

Section: Sample Analysismentioning

confidence: 99%

“…It could be assumed that in this case every surface element reaches the Results of the XRD analyses: texture parameter η t , overlap Σ, strain ε and grain size D as obtained by WHP and WA, and film thickness t for different lateral shifts δ (v scan = 30 mm/s, d b = 1.00 mm, f = 100 Hz) FIGURE 10 WHP plot for different lateral shifts. The scan parameter are shown in Table 1 FIGURE 11 Derived microstrain and grain size as a function of the lateral shift evaporation point. Additionally, all melting droplets and melt remains will be destroyed.…”

Section: Influence Of the Lateral Shift And Scan Repetitionmentioning

confidence: 99%

“…Alternatively, it is possible to treat the surface with laser radiation and to directly synthesize hard coatings [4][5][6][7][8]. Previous works have shown the successful synthesis of titanium nitride with laser irradiation [9][10][11]. Here, a Q-switched Nd:YAG laser was used for the nitriding treatment.…”

Section: Introductionmentioning

confidence: 99%

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Microstructure of TiN coatings synthesized by direct pulsed Nd:YAG laser nitriding of titanium: Development of grain size, microstrain, and grain orientation

et al. 2008

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Pure titanium was irradiated by pulsed Nd:YAG laser irradiation in nitrogen atmosphere. As a result, nitrogen uptake and diffusion occurred and a TiN layer was synthesized at the titanium surface. These TiN coatings were analyzed by X-ray diffraction and the diffraction patterns were investigated in detail, in order to obtain more information about the physical processes during the coating formation. The diffraction peaks were fitted by Pearson VII profiles and the grain size and the microstrain were determined by the analysis of line broadening and peak shifts, using the Williamson-Hall and the Warren-Averbach formalisms. Additional single-line analyses were performed by means of the method of Langford and Keijser to obtain information about the preferred grain orientation and the texture development. The maximum grain size was about 100 nm and a corresponding average lattice strain of 0.002 was found. A relation between the treatment parameters and the coating properties, such as grain size and microstrain, can be shown. Thus, it was possible to determine optimal scan parameters for material processing and to establish the physical limits of the coating properties.PACS 81.65.Lp; 81.15.Fg; 61.10.Nz; 68.55.Jk IntroductionNitriding and carburizing of metals are well known techniques to improve the tribological properties like hardness and wear resistance of technical surfaces [1]. As an example, plasma-and gas nitriding are established methods for surface treatment [2,3]. Alternatively, it is possible to treat the surface with laser radiation and to directly synthesize hard coatings [4][5][6][7][8]. Previous works have shown the successful synthesis of titanium nitride with laser irradiation [9][10][11]. Here, a Q-switched Nd:YAG laser was used for the nitriding treatment. The main advantages of this method are a reduction of the processing time and the negligible heat load for the workpiece. Stress, microstrain and inhomogeneity remain the main problems. Also the texture of cubic titanium nitride is a decisive factor for the technical quality of the coatings, as the u Fax: +49-551-39-4493, E-mail: pschaaf@uni-goettingen.de texture influences strain development and finally crack formation and propagation. Some investigations on texture and strain development in relation to the process parameters have been reported in the literature [12][13][14].This work resolves the resulting grain size and strain development and relates them to laser treatment parameters like scan parameters. In this way, one can try to predict optimum treatment parameters for optimum coating properties, i.e. find parameters that minimize the lattice strain in order to reduce crack formation and propagation. Experiments 2.1 Sample treatmentConventional α-titanium (purity > 99.98%) was used for the treatments. Titanium sheets of 1 mm thickness were cut into pieces of 15 × 15 mm 2 and used in the asreceived state without any further treatment.For laser nitriding, the samples were placed in a chamber which was first evacuated and then fil...

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“…As expected, the coating thickness t -measured by cross section SEM [11] -decreases with increasing scan velocity.…”

Section: 1supporting

confidence: 80%

Section: Sample Analysismentioning

confidence: 99%

Section: Influence Of the Lateral Shift And Scan Repetitionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Microstructure of TiN coatings synthesized by direct pulsed Nd:YAG laser nitriding of titanium: Development of grain size, microstrain, and grain orientation

et al. 2008

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“…In this work, coatings several microns in thickness were synthesized. In other experiments, [4,5] TiN coatings were generated for the first time by means of a free electron laser (FEL). Due to its high power and the flexibility in its temporal shaping, this type of laser could be the right tool.…”

Section: Introductionmentioning

confidence: 99%

Marangoni Convection during Free Electron Laser Nitriding of Titanium

Höche

Müller

Rapin³

et al. 2009

Metall Mater Trans B

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Pure titanium was treated by free electron laser (FEL) radiation in a nitrogen atmosphere. As a result, nitrogen diffusion occurs and a TiN coating was synthesized. Local gradients of interfacial tension due to the local heating lead to a Marangoni convection, which determines the track properties. Because of the experimental inaccessibility of time-dependent occurrences, finite element calculations were performed, to determine the physical processes such as heat transfer, melt flow, and mass transport. In order to calculate the surface deformation of the gasliquid interface, the level set approach was used. The equations were modified and coupled with heat-transfer and diffusion equations. The process was characterized by dimensionless numbers such as the Reynolds, Peclet, and capillary numbers, to obtain more information about the acting forces and the coating development. Moreover, the nitrogen distribution was calculated using the corresponding transport equation. The simulations were compared with crosssectional micrographs of the treated titanium sheets and checked for their validity. Finally, the process presented is discussed and compared with similar laser treatments.

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Parameter settings in a compact laser‐nitriding system for titanium composed of a focused pulsed Nd:YAG laser and nitrogen gas blow

Ohtsu

Saito

Yamane

2018

Surface & Interface Analysis

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The aim of the present study was to form a nitride layer on a titanium (Ti) substrate through a compact laser‐nitriding system comprising a focused pulsed Nd:YAG laser and nitrogen gas blow. To obtain a high‐quality layer, the effects of pulse frequency and gas flow rate on the surface characteristics were investigated by using plasma emission analysis as well as X‐ray analyses. Optical emission spectra from the laser‐induced plasma mainly consisted of ionic Ti lines, and their intensities when the pulse frequency was 15 Hz were much higher than those for 8 Hz. Similarly, the reflections from the δ‐TiN phase in the X‐ray diffraction (XRD) pattern were enhanced when using 15 Hz. On the other hand, the flow rate of nitrogen gas blow had a significant effect on the thickness of the thin oxide layer that formed above the nitride layer. Using a lower flow rate resulted in the formation of a thicker oxide layer. The higher pulse frequency and the faster flow rate were beneficial for obtaining a higher‐quality layer because of the enhancement of nitridation and the suppression of oxidation, respectively.

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Laser pulse structure dependent texture of FEL synthesized TiN_xcoatings

Cited by 23 publications

References 24 publications

Microstructure of TiN coatings synthesized by direct pulsed Nd:YAG laser nitriding of titanium: Development of grain size, microstrain, and grain orientation

Microstructure of TiN coatings synthesized by direct pulsed Nd:YAG laser nitriding of titanium: Development of grain size, microstrain, and grain orientation

Marangoni Convection during Free Electron Laser Nitriding of Titanium

Parameter settings in a compact laser‐nitriding system for titanium composed of a focused pulsed Nd:YAG laser and nitrogen gas blow

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Laser pulse structure dependent texture of FEL synthesized TiNxcoatings

Cited by 23 publications

References 24 publications

Microstructure of TiN coatings synthesized by direct pulsed Nd:YAG laser nitriding of titanium: Development of grain size, microstrain, and grain orientation

Microstructure of TiN coatings synthesized by direct pulsed Nd:YAG laser nitriding of titanium: Development of grain size, microstrain, and grain orientation

Marangoni Convection during Free Electron Laser Nitriding of Titanium

Parameter settings in a compact laser‐nitriding system for titanium composed of a focused pulsed Nd:YAG laser and nitrogen gas blow

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Laser pulse structure dependent texture of FEL synthesized TiN_xcoatings