Laser nitriding: investigations on the model system TiN. A review

Abstract

Nitriding is a well known technique to improve properties of materials. The process utilizing laser contains many different processes like heat transport and melting effects, diffusion and convection, which partially determine the synthesized coatings. This review concludes the research on titanium nitride synthesis in reactive ambient and draws conclusions for the general handling of the method. Afterwards, it becomes clear which and why, transport processes limit the coating properties. IntroductionHard material systems such as titanium nitride play an important role within the field of material sciences and industrial applications. In particular wear and corrosion protection are based on such systems. Beside the classical manufacturing procedures such as PVD or CVD, the method of the direct laser synthesis in a reactive gas environment, as examined here, represents an alternative to the production of such coatings. This review discusses the synthesis of such functional coatings on the system titanium -nitrogen by different laser irradiation based on own results respectively the literature and tries to give a general overview of the physical respectively transport processes taking place. Thus, experiments from the last three decades using similar experimental setups will be compared and discussed. Due to the availability of data of investigations utilizing titanium and nitrogen, this system was taken as a general model. After a discussion of several different experimental analyses and modelling results, the treatments get parameterized. This results in large potentials for technical applications. Finally, general conditions for the synthesis of such coatings with this procedure were set up. By means of these results it is possible to achieve purposefully predefined layer characteristics. The review concludes the most important publications containing research about this process. Thus, it could be assumed to be a reference in relation to laser nitriding or -carburizing. [4] or also hybrid procedures. A further alternative and very simple method is the direct lasers synthesis. The material is placed in a reactive gas environment and will be irradiated with laser light. Due to the developing physical and chemical effects coatings are synthesized, which possess special treatment dependent characteristics. Carburizing, nitro carburizing and/or nitriding are to most common methods from this field of processes. The method of nitriding particularly assists the improvement of tribological properties of surfaces. The surface hardness gets increased, whereby the wear resistance rises. Furthermore, these coatings are usually very non-reactive, which leads to an increase in corrosion protection. In the following the method will be studied more exactly and will be explained. Quantifying of the processes gets an important aim of the work. Arising phenomena will also be modelled. To do these investigations, the model titanium nitrogen has been used. It is a well known and often used system, and has been investigated ...

Laser Gas–Assisted Nitriding of Ti Alloys

“…The laser-material processing by laser pulses on different time scales has been discussed in various overview articles (28,118) and books (119,120). For femtosecond (fs) pulses, the thermal formulation of the laser-material interaction does not work.…”

“…It has been established that short laser pulses of high energy can induce a direct synthesis of thin wear-resistant layers if the surface of titanium alloys is irradiated in a reactive atmosphere (6,27,28). Successful tests of the direct laser synthesis have been carried out with Excimer (29,30), Nd:YAG (31)(32)(33)(34)(35), titanium-sapphire (36), and free electron lasers (FELs) (37)(38)(39)(40) in nitrogen and methane atmospheres.…”

Laser nitriding of niobium for application to superconducting radio-frequency accelerator cavities

“…3 The beam dimensions and thermal diffusion length permit modeling in one dimension to predict the time course of the surface temperature for a range of per-pulse energy densities. Cost-for-performance is critical, both in terms of initial capital outlay and ongoing operating expense, especially for electricity.…”

“…3 GHz decreases from about 800 nX at 4.2 K to 15 nX at 2 K. 4 The quality factor Q 0 (2p times the ratio of stored energy to energy loss per cycle) is inversely proportional to the surface resistance and may exceed 10 11 . 3 GHz decreases from about 800 nX at 4.2 K to 15 nX at 2 K. 4 The quality factor Q 0 (2p times the ratio of stored energy to energy loss per cycle) is inversely proportional to the surface resistance and may exceed 10 11 .…”

“…3 The beam dimensions and thermal diffusion length permit modeling in one dimension to predict the time course of the surface temperature for a range of per-pulse energy densities. Sci.…”