In this work, we investigate the relation between the diffusion behavior of Ti1-xAlxN at elevated temperatures and the microstructure. Thinfilm samples are synthesized by reactive co-sputtering with two cathodes. One cathode equipped with Ti target is connected to a highpower impulse magnetron sputtering (HiPIMS) power supply, and the other cathode equipped with Al target is operated with a directcurrent power source. The spinodal decomposition of cubic metastable Ti1-xAlxN controlled by thermally activated diffusion is observe fordiffusion behavior. Various HiPIMS pulsing frequencies are used to achieve different microstructure, while altered power applied to Altarget is used to change the Al content in films. In the phase composition analysis achieved by GI-XRD, the right-shift of (111) film peakalong with increasing Al-power is observed. A saturation of the right-shift and h-AlN peaks are also observed at certain Al-power. Thechemical composition determined by ERDA shows trends of reducing Al solubility limit in metastable phase and O contamination upondecreasing the pulsing frequency. More N deficiency is found in samples deposited with higher frequency. In the 500 Hz and 250 Hzsamples deposited into similar composition and thickness, no apparent difference of the microstructure is observed from the SEM crosssectionalimages. From HT-XRD, we observe higher intensity of TiO2 and h-AlN peaks in 500 Hz sample at elevated temperature ascompared with 250 Hz one. From the reduction of O contamination, denser Ti1-xAlxN films are able to be deposited with lower HiPIMSpulsing frequency. In addition, the higher intensity observed in HT-XRD patterns indicates that the 500 Hz sample is more open todiffusion and therefore allows the new formed phases to grow in larger grains.

Dans la perspective du développement de vitrages électrochromes « en milieu protonique », des films minces électrochromes à coloration anodique, à base d’oxyde de nickel, ont été synthétisés et caractérisés. Afin d’améliorer la durabilité des films minces à base de NiO, trois approches ont été envisagées. (i)Des films d’oxyde de nickel et d’oxyde mixte nickel/lithium, déposés par PLD (Pulsed Laser Deposition). Nous avons étudié l’influence du lithium sur les propriétés physico-chimiques (‘amorphisation..), et les caractéristiques électrochromes (électrochimique-optique) en milieu aqueux KOH 1M. (ii) Des films composites, préparés par voie chimique (solution), constitués d’une phase amorphe (en diffraction des Rayons X), de composition Ti1-xZnxO2-x?x, englobant des cristallites de NiO de ~ 5 nm de diamètre. Les courbes voltampérométriques révèlent que seule la phase NiO est électrochimiquement active, mais la phase amorphe, grâce aux lacunes anioniques neutres, ?x, renforce la tenue mécanique des films déposés sur les substrats FTO/verre. Il s’ensuit que ces films composites sont plus stables au cyclage, en milieu aqueux KOH 1M, que leurs homologues TiO2/NiO. (iii) Des films minces d’oxyde de nickel dopés par du carbone, préparés par une voie sol-gel originale, présentant une remarquable tenue en cyclage (> 25000 cycles en milieu aqueux KOH 1M), jamais observée jusqu’ici pour NiO. / Aiming at enhancing the electrochromic properties of NiO thin films, deposited on FTO substrates, we have employed three different approaches. They deal with: 1) lithium doping of NiO, the corresponding thin film-deposition method is PLD (Pulsed Laser Deposition); 2) NiO nanoparticles embedded into zinc doped amorphous titanium oxide matrix, a solution method is used to deposit the corresponding thin films ; 3) Carbon-doped NiO thin films deposited using, a specific sol-gel method. Owing to lithium doping of NiO, we could induce film amorphization, thereby enhancing the film electrochemical-capacity. Most importantly, the adhesion between the film and the FTO substrate was improved leading to enhanced electrochemical cyclability in aqueous KOH electrolyte. We could enhance the electrochromic performances of TiO2/NiO composite thin films by doping TiO2 with Zn2+, forming to a new composite thin film Ti1-xZnxO2-x?x-NiO. Finally we have successfully stabilized the electrochromic properties (durability and optical property) of NiO thin films in aqueous KOH electrolyte, owing to the development of a specific sol-gel method leading to carbon-doped NiO nanoparticles. For the first time 25000 cycles were successfully achieved without significant decrease of the electrochromic performances.

Dans la perspective du développement de vitrages électrochromes « en milieu protonique », des films minces électrochromes à coloration anodique, à base d'oxyde de nickel, ont été synthétisés et caractérisés. Afin d'améliorer la durabilité des films minces à base de NiO, trois approches ont été envisagées. (i)Des films d'oxyde de nickel et d'oxyde mixte nickel/lithium, déposés par PLD (Pulsed Laser Deposition). Nous avons étudié l'influence du lithium sur les propriétés physico-chimiques (‘amorphisation..), et les caractéristiques électrochromes (électrochimique-optique) en milieu aqueux KOH 1M. (ii) Des films composites, préparés par voie chimique (solution), constitués d'une phase amorphe (en diffraction des Rayons X), de composition Ti1-xZnxO2-x□x, englobant des cristallites de NiO de ~ 5 nm de diamètre. Les courbes voltampérométriques révèlent que seule la phase NiO est électrochimiquement active, mais la phase amorphe, grâce aux lacunes anioniques neutres, □x, renforce la tenue mécanique des films déposés sur les substrats FTO/verre. Il s'ensuit que ces films composites sont plus stables au cyclage, en milieu aqueux KOH 1M, que leurs homologues TiO2/NiO. (iii) Des films minces d'oxyde de nickel dopés par du carbone, préparés par une voie sol-gel originale, présentant une remarquable tenue en cyclage (> 25000 cycles en milieu aqueux KOH 1M), jamais observée jusqu'ici pour NiO.

<p>The high pressure and high temperature (HPHT) behavior of Ti_1-xAl_xN coatings on cutting tool inserts have been of interest for this diploma work. A literature study of HPHT techniques as well as measurement methods has been done. A diamond anvil cell (DAC) would be a good device to achieve high pressure and high temperature conditions on small samples. Another way to obtain these conditions would be a cutting test, which has been performed on a Ti_1-xAl_xN coated cutting tool insert with x = 0.67. Also a cubic press could be used to apply HPHT on a     Ti_1-xAl_xN sample or a large volume press on a whole cutting tool insert. To measure hardness on thin coatings a nanoindentor could be used, which have been done on heat-treated Ti_0.33Al_0.67N and TiN samples. X-ray diffraction (XRD) is a suitable method to measure phase composition of a sample and was performed on the cutting tested insert as well as on an untreated reference insert. Three ways to continue this project have been outlined all starting with more comprehensive cutting tests.</p>

The high pressure and high temperature (HPHT) behavior of Ti1-xAlxN coatings on cutting tool inserts have been of interest for this diploma work. A literature study of HPHT techniques as well as measurement methods has been done. A diamond anvil cell (DAC) would be a good device to achieve high pressure and high temperature conditions on small samples. Another way to obtain these conditions would be a cutting test, which has been performed on a Ti1-xAlxN coated cutting tool insert with x = 0.67. Also a cubic press could be used to apply HPHT on a     Ti1-xAlxN sample or a large volume press on a whole cutting tool insert. To measure hardness on thin coatings a nanoindentor could be used, which have been done on heat-treated Ti0.33Al0.67N and TiN samples. X-ray diffraction (XRD) is a suitable method to measure phase composition of a sample and was performed on the cutting tested insert as well as on an untreated reference insert. Three ways to continue this project have been outlined all starting with more comprehensive cutting tests.