The development of large stresses during lithiation and delithiation drives mechanical and chemical degradation processes (cracking and electrolyte decomposition) in thin film silicon anodes that complicate the study of normal electrochemical and mechanical processes. To reduce these effects, lithium phosphorous oxynitride (LiPON) coatings were applied to silicon thin film electrodes. Applying a LiPON coating has two purposes. First, the coating acts as a stable artificial solid electrolyte interphase. Second, it limits mechanical degradation by retaining the electrode's planar morphology during cycling. The development of stress in LiPON-coated electrodes was monitored using substrate curvature measurements. LiPON-coated electrodes displayed highly reproducible cycle-to-cycle behavior, unlike uncoated electrodes which had poorer coulombic efficiency and exhibited a continual loss in stress magnitude with continued cycling due to film fracture. The improved mechanical stability of the coated silicon electrodes allowed for a better investigation of rate effects and variations of mechanical properties during electrochemical cycling.
The thermal stability and the diffusion barrier properties of DC reactively sputtered tantalum oxynitride (Ta-O-N) thin films, between silver (Ag) and silicon (Si) p + n diodes were investigated. Both materials characterization (X-ray diffraction analysis, Rutherford backscattering spectrometry (RBS), Auger depth profiling) and electrical measurements (reverse-biased junction leakage current-density) were used to evaluate diffusion barrier properties of the thin films. The leakage current density of p + n diodes with the barrier (Ta-O-N) was approximately four orders of magnitude lower than those without barriers after a 30 min, 400 deg. C back contact anneal. The Ta-O-N barriers were stable up to 500 deg. C, 30 min anneals. However, this was not the case for the 600 deg. C anneal. RBS spectra and cross-sectional transmission electron microscopy of as-deposited and vacuum annealed samples of Ag/barrier (Ta-O-N)/Si indicate the absence of any interfacial interaction between the barrier and substrate (silicon). The failure of the Ta-O-N barriers has been attributed to thermally induced stresses, which cause the thin film to crack at elevated temperatures
Sonos 7.4 Crack
We report the growth of InGaN/GaN multiple quantum wells blue light-emitting diodes (LEDs) on a silicon (111) substrate with an embedded nanoporous (NP) GaN layer. The NP GaN layer is fabricated by electrochemical etching of n-type GaN on the silicon substrate. The crystalline quality of crack-free GaN grown on the NP GaN layer is remarkably improved and the residual tensile stress is also decreased. The optical output power is increased by 120% at an injection current of 20 mA compared with that of conventional LEDs without a NP GaN layer. The large enhancement of optical output power is attributed to the reduction of threading dislocation, effective scattering of light in the LED, and the suppression of light propagation into the silicon substrate by the NP GaN layer.
Research highlights: Oxidation of phi'-AlON has been studied for the first time. First corrosion products are gamma-alumina. Low density alpha-alumina is formed at high temperature. Grains are extensively cracked after oxidation. The low density of the alpha-alumina is due to a network of nanometric porosities. - Abstract: The oxidation in air of single crystal phi'-aluminium oxynitride (AlON) grains has been characterized by thermogravimetry and X-ray diffraction in the 1273-1673 K range. Two oxidation stages have been observed, suggesting the formation of a transitional phase. Below 1473 K, oxidation results in the apparition of platelets and noodle-like crystals on the surface of the initially faceted single crystals. Above 1473 K, low density alpha-alumina polycrystals start forming on the grain surface and grow towards the grain core with increasing temperature or time. Their low density is mainly due to the presence of a network of nano-porosities.
A systematic study of the mechanical deformation and failure of transparent ceramic aluminum oxynitride (AlON) has been conducted using a depth-sensitive nanoindentation technique combined with transmission electron microscopy (TEM) and Raman spectroscopy. Although discrete displacement bursts appear in the load-depth profiles at high applied forces, a detectable high-pressure phase transition has not been found by means of micro-Raman spectroscopy and TEM. Instead, a high density of dissociated dislocations can be observed underneath the nanoindenters, suggesting that extensive plastic deformation takes place in the brittle ceramic at high contact pressures. Moreover, nanoindentation-induced micro-cracks oriented along well-defined crystallographic planes can also be observed, consistent with the low fracture toughness of AlON evaluated by an indentation method using Laugier's equation.
In this research Fe-3%Cr-3%Mo-3%Si and Fe-3%Cr-3%Cu-3%Si alloys had been coated by silicon metal without electricity current which knows as electroless siliconizing. Coating was conducted by immersed sampler into melt fluoride-chloride salt bath at temperature of 750 o C for certain period. The layer consisted of Fe3Si phase. Observation by microscope optic and EDAX showed that the silicide layer were thick enough, adherent, free for crack and had silicon content on the surface more than 15%. The growth rate of silicide layer followed parabolic rate law, where the process predominantly controlled by interdiffusion rate in the solid phase. Key words : electroless siliconizing, the melt fluoride- chloride salt mix, silicide layer
The main issue in homoepitaxial growth of aluminum nitride (AlN) on native seed substrates is the formation of an aluminum oxynitride (AlON) layer at temperatures between 1850-1950 C leading to polycrystalline growth. On the contrary, heteroepitaxial growth of AlN on silicon carbide (SiC) is relatively easy to achieve due to natural formation of a thin molten layer of (Alsub 2OCsub x) on the seed surface and consequent growth of AlN via the molten buffer layer. Optimization of the seeding process can be achieved by use of ultra-pure starting material. Another critical issue of AlN growth on SiC is cracking of the grown layer upon cooling as a result of different thermal expansion coefficients. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)
Fracture and environmentally assisted subcritical crack-growth processes are examined in bulk Y-Si-Al-O-N oxynitride glasses with compositions typical of the grain boundary phase of silicon nitride ceramics. Both long-crack (in compact tension specimens) as well as short-crack behavior (using indentation techniques) were investigated to establish a reliable fracture toughness and to elucidate the anomalous densification behavior of the oxynitride glass. Environmentally assisted subcritical crack-growth processes were studied in inert, moist, and wet environments under both cyclic and static loading conditions. Behavior is discussed in terms of the interaction of the environment with the crack tip. Likely mechanisms for environmentally assisted crack growth are discussed and related to the subcritical crack-growth behavior of silicon nitride ceramics
As a dryer it seems fine. However, since haviing it installed on May 18th we have had GE service called out twice. First issue was a crack in the plastic by the lint trap. Second issue is occasionally the dryer will continue to tumble after the door had been opened. also had to have the door loosened as it was very tight when it arrived. Service person in our area is very personable and good but sadly, I am on a first name basis with him now.Originally posted on www.ge.com
The container has a 450ml capacity, and the material is borosilicate glass. In other words, this means it will not crack under extreme temperature changes like regular glass. Likewise, the material completely changes the behavior of glass and makes it thermal shock resistant. This material has been crafted to redefine durability.
Unsurprisingly, Apple did not crack the top five estimated vendors on Gartner's worldwide data, so its global performance remains unknown. Total worldwide PC sales are forecast to have fallen 6.9 percent year over year in the December frame, according to the data released on Thursday.
Model Design / Appearance*(7.0)*Nikon has pulled together the styling of its DSLR line. The contours are defined with curving ridges and rounded planes, and the Nikon logo appears on the viewfinder hump. The squat red triangle on the handgrip designates this camera as a Nikon from first glance. The D40 is small, and that detracts a bit from the imposing, no-nonsense presence of larger Nikon DSLRs. The D40 looks and feels cheaper than its stable-mates. The plastic components don't fit together as tightly as they do on higher-end Nikons, leaving small cracks in the body. That's disappointing because it suggests that dust and dirt can get inside through the gaps and shorten the camera's life. Though the D40 doesn't measure up to other Nikons, high-end Canons, or Olympus DSLRs by this measure, it has better fit and finish than the Canon EOS Rebel XTi. Nikon dropped the monochrome LCD from the D40. Other Nikons, from the D70 up, have simple displays on the top deck that show a range of shooting parameters. The D40 uses the color LCD on the back for that information. A monochrome LCD wouldn't fit on the small D40, and Nikon surely saved money by leaving off an extra display and its related electronics. **Size / Portability***(8.0)*The Nikon D40 measures 5 x 2.5 x 3.7 inches and weighs 17 ounces without a lens or battery. Ready to shoot with the kit lens, the D40 tips the scales at 26 ounces, making it very light indeed. Like all DSLRs, it is irregularly shaped and needs its own carrying case in most situations. The D40 is relatively delicate, and that limits its portability. The kit lens is flimsy, and both the lens and the camera body are vulnerable to dust and moisture. It's not the camera for the beach or the tour boats at Niagara Falls.Handling Ability*(7.0)*Users with large hands will find the Nikon D40 inconvenient to use because the grip is relatively small, and the space between the grip and the mount is narrow. We didn't mount any of Nikon's fat, wide-aperture lenses to the D40, but we bet there isn't much of a gap between the barrel of the wide-aperture zooms and its grip. 2ff7e9595c
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