China 
Africa 
Explore chapters and articles related to this topic
Glasses
Published in Marvin J. Weber, and TECHNOLOGY, 2020
Although improvements in the fatigue resistance of high-silica fibers have been achieved through compositional modification of the cladding glass,8,9 most of the work in this area has concentrated on the development of hermetic coatings. The first coating materials investigated in this context were low-melting metals, including aluminum, lead, and tin.10–12 Problems with pinholes in the coatings, their poor adhesion to the glass, and excessive fiber bend loss have restricted this approach. Hydrogen can also permeate through the metal coatings. Alternative CVD-deposited ceramic coatings, such as silicon-oxynitride, have been used with more success.13,14 The initial strengths of such fibers are typically lower than uncoated fibers, but their subsequent degradation is slower (see Figure 18.2.3).15 These ceramic coatings can provide an effective barrier against hydrogen permeation.
Rapid Thermal Processing
Published in Robert Doering, Yoshio Nishi, Handbook of Semiconductor Manufacturing Technology, 2017
Silicon that is exposed to nitrogen-bearing gas will typically grow an oxynitride film, because the thermodynamics of the silicon–oxygen–nitrogen system make it extremely difficult to form a pure nitride layer when there is even the tiniest amount of oxygen-bearing gas present [232]. However, the reaction of silicon with ultra-pure ammonia gas results in a film that is mainly silicon nitride [233,234]. At any given temperature, the nitridation tends to be self limiting, because silicon nitride is an excellent diffusion barrier. Figure 11.58 shows an example of RTN kinetics for very thin nitride films formed in ammonia [234]. Silicon has also been nitrided by RTP in N2 or N2/O2 mixtures [235–237]. For processing in “pure” N2, the behavior is complex, because the formation of silicon nitride or oxynitride films may be governed by the presence of extremely small concentrations of background impurities in the gas ambient, especially H2O, CO2, and O2, which may be present as a result of outgassing from chamber walls [235]. Several studies have reported the growth on SiON films in N2 ambients, and this approach provides a way to form very thin oxynitrides with relatively high N content.
Systems Based on GaN
Published in Tomashyk Vasyl, Ternary Alloys Based on III-V Semiconductors, 2017
Ga2.81O3.57N0.43 was crystallized under high-pressure, high-temperature conditions in a spinel-type structure from a prestructured gallium oxynitride ceramic, which was obtained from the single-source molecular precursor [Ga(OBut)2NMe2]2 by thermal treatment in an ammonia atmosphere (Kinski et al. 2005b). The optimized precursor-derived gallium oxynitride ceramic remains nanocrystalline up to 600°C and can be transformed at 7 GPa and 1100°C into the crystalline phase with the same composition. All reactions and operations were carried out under inert conditions with rigorous exclusion of oxygen and moisture.
Biomedical applications of polymer and ceramic coatings: a review of recent developments
Published in Transactions of the IMF, 2022
J. R. Smith, D. A. Lamprou, C. Larson, S. J. Upson
Although PLLA is a promising biodegradable polymer within cardiac research, it does have some disadvantages including high hydrophobicity and reduced cell adhesion. Bolbasov et al. modified the surface of PLLA with a thin titanium oxynitride (TiOxNy) / titanium nitride (TiNx) / TiO / TiO2 mixed coating utilising reactive magnetron sputtering within a nitrogen atmosphere.80 Various plasma treatment times were evaluated to reveal that physico-mechanical properties of the scaffold remained unchanged and hydrophobicity was decreased. No adverse tissue reaction was documented during in vivo subcutaneous implantation (Wistar rats) of the modified PLLA scaffolds up to 3 months and re-growth of replacement tissue was discerned to depend upon plasma treatment time.
Basic properties mapping of anodic oxides in the hafnium–niobium–tantalum ternary system
Published in Science and Technology of Advanced Materials, 2018
Andrei Ionut Mardare, Cezarina Cela Mardare, Jan Philipp Kollender, Silvia Huber, Achim Walter Hassel
Hafnium, niobium and tantalum have similar electrochemical characteristics in that they are all valve metals. This classification and its name are based on their current rectification upon electric field reversal (hence, the name ‘valve’) during metals anodisation under high field conditions. The final anodic oxide thickness is proportional to the applied potential and oxide formation factors of 2.3, 2.6 and 1.8 nm V−1 were measured for Hf, Nb and Ta, respectively [11]. The oxides of the aforementioned pure metals have applications in various fields. Due to its high dielectric constant and excellent thermal stability, hafnium oxide is investigated mainly as a gate material for field effect transistors and supercapacitors, while hafnium oxynitride is studied as a catalyst for oxygen reduction reactions [12,13]. Additionally, Hf1−xTaxO2 based memristors with excellent bipolar resistive switching characteristics were recently demonstrated, which promote the use of mixed Hf and Ta oxides in modern electronics [14]. The spectrum of niobium oxide applications is broad, ranging from use in capacitors to applications in electrochromic devices, gas sensors and solar cells [15–18]. Applications of Ta2O5 are found in the same major areas. Tantalum oxides, usually applied in high power resistors and capacitors, started recently to be investigated for cathodes in fuel cells, lithiation support in batteries and counter electrodes in solar cells [19–22].
Oxidized coal flotation enhanced by adding n-octylamine
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2018
Mengdi Xu, Yaowen Xing, Ming Li, Wei Jin, Yijun Cao, Xiahui Gui
XPS N1s peaks of the oxidized coal after diesel and DO conditioning are shown Figure 5. The peaks of the binding energies at 398.8, 400.2, 401.4, and 402.9 eV represent the pyridinic, pyrrolic, oxynitride, and quaternary nitrogen groups, respectively (Kozłowski 2004). Peak split results of N of oxidized coal after diesel and DO conditioning are listed in Table 1. It was found that the content of quaternary nitrogen after DO conditioning was much higher than that after diesel conditioning, which were 18.24% and 11.60%, respectively. This illustrated that the positive-charged amidogen in n-octylamine absorbed at negative-charged oxidized coal surface, increasing the water contact angle and final flotation recovery. Based on this, the schematic of the interaction mechanism between DO and oxidized coal surface is drawn in Figure 6. The n-octylamine molecule first occupied at the more negative-charged hydrophilic sites through electrostatic bonding. The left less negative-charged hydrophobic sites were then covered by diesel. As a result, a complete oil film was formed on oxidized coal and thus enhancing flotability.