Materials Literature
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Chromium nitride (CrN) coatings have been deposited on polished steel substrates by a plasma-beam sputtering technique in a Sputron apparatus (Balzers A. G.) at 200 °C. A thin intermediate layer of Cr (0.08 μm) was deposited between the substrate and the 2.8 μm thick CrN coating. The average roughness, Ra, of the subs…
Abstract Pb monoborate hydrate, Pb 5 B 3 O 8 (OH) 3 H 2 O, was synthesized in the hydrothermal system PbCO 3 –Li 2 B 4 O 7 –H 2 O ( T = 543 K, p = 100 bar; PbCO 3 /Li 2 B 4 O 7 = 0.25–0.5; 10–14 days). The hexagonal structure was established from X-ray single crystal diffraction, λ (Mo K α ) = 0.71073 Å; space group P…
The paper deals with gel permeation chromatography (GPC) monitoring of the behaviour of PET (polyethylene terephthalate) after repeated extrusions. Virgin PET was submitted to three successive extrusion/drying cycles and then the samples were swelled with hexafluoroisopropanol and treated with chloroform. GPC analysis…
Abstract In this paper, we review some of the significant synthesis approaches that we and others have evaluated for producing commercially viable water‐soluble biodegradable polymers. The goals set for these polymers, cost/performance equivalent with current non‐biodegradable polymers and complete biodegradation or a…
Ca (1+ x )/2 Sr (1+ x )/2 Zr 4 P 6−2 x Si 2 x O 24 ( x ≤ 0.37) compositions, which belong to the [NZP] family of low‐thermal‐expansion materials, were synthesized using the solid‐state reaction method. The lattice thermal expansion of members of this system was determined up to 1000°C by high‐temperature X‐ray diffrac…
Abstract The objective of this research is to synthesize synthetic biodegradable polymers that would have biological functions similar to nitric oxide. Polyglycolide (PGA) was the synthetic biodegradable polymer and 4‐amino‐2,2,6,6‐tetramethylpiperidine‐1‐oxy (Tempamine) was chosen as the source of nitroxyl radicals.…
The structure of a \[0001]/31.5o tilt boundary in ZnO has been investigated using high-resolution electron microscopy. In some regions the interface structure is best described by reference to the periodic dichromatic pattern corresponding to the misorientation \[0001]/32.5o ( Sigma = 13). These regions exhibit arrang…
The formulation consisting of 50ppm ATMP and 300ppm MoO 4 2‐ had only 32 per cent efficiency in inhibiting the corrosion of mild steel immersed in a neutral aqueous environment containing 60ppm C1 ‐ , whereas the ATMP (50ppm) ‐ MoO 4 2‐ (300ppm) ‐ Zn 2+ (50ppm) system had 96 per cent inhibition efficiency. The lower i…
Near‐stoichiometric mullite (3Al 2 O 3 2SiO 2 ) that contained small amounts of calcium and magnesium was exposed to pure dry hydrogen gas at elevated temperatures. Exposure temperatures were 1050° and 1250°C, and exposure times were up to 500 h. Preferential attack of the aluminosilicate glass that was present in the…
Abstract The kinetic crystallization model of Avrami is generally accepted as a starting point for the analysis of isothermal polymer crystallization. It is shown in this paper that, in the case of non‐isothermal crystallization kinetics with constant heating or cooling rates, an apparent m ‐order reaction model is ap…
Aromatic polyesters were prepared and used to decrease the brittleness of the bismaleimide resin composed of 4,4′-bismaleimidediphenyl methane (BMI) and o,o′-diallyl bisphenol A (DBA) (Matrimid 5292 resin). The aromatic polyesters included poly(propylene phthalate) (PPP), poly(2,2-dimethylpropylene phthalate) (PDPP),…
Plasticity theory is extended to incorporate strain rate effects on the residual shear strength of clays. The clay is assumed to behave elastically before yielding and then in a perfectly plastic manner with no volume change during yielding. The Mohr-Coulomb failure criterion is used in the rate-dependent model in whi…
Corrosion behavior of two stainless steels (SS) was investigated in nitric acid (HNO3) for the effect of cold work (CW), sensitization heat treatment (Sens.), and a combination (CW + Sens.). The corrosion rate of the solution-treated type 304 SS (UNS S30400) with extra-low carbon (type 304ELC SS [UNS S30403]) increase…
A fast method for measuring the power density distribution of electron beams has been developed. The method employs a refractory metal disc containing regularly spaced radial slits and a Faraday cup to measure electron beam profiles as the beam is oscillated in a circular pattern over the disc. This beam profiling met…
Cobaltphthalocyaninat(2–) reagiert mit Tetra(n-butyl)ammoniumboranat in Aceton zu leichtlöslichem Tetra(n-butyl)ammoniumphthalocyaninato(2–)cobaltat(I). Die olivgrünen Plättchen des Aceton-Solvats kristallisieren in der monoklinen Raumgruppe P1 21/c (Nr. 14) mit den Zellparametern a = 12,370(1) Å, b = 23,370(3) Å, c =…
Regardless of environment (ultrahigh vacuum, humid air, dry nitrogen, or water), ion-beam-deposited diamondlike carbon (DLC) and nitrogen-ion-implanted, chemical-vapor-deposited (CVD) diamond films had low steady-state coefficients of friction (<0.1) and low wear rates (≤ 10−6 mm3/N·m). These films can be used as e…
Raman spectra of polycrystalline samples of CH3NH3PbC13 were studied at between 80 and 300 K. An assignment of most of the observed bands is proposed. The first-order phase transitions previously detected at 172 and 179K were characterized: The spectral evolution and the mechanism proposed are in agreement with the th…
The calibration constants that link the peak-shift measured with X-rays to the macroscopic stress acting on the material are termed X-ray elastic constants. These terms contain both material parameters such as the elastic stiffness or compliance terms and configurational parameters caused by the Miller indices of the…
The environment around Li in a ${\mathrm{LiAlSiO}}_{4}$ glass has been studied by neutron scattering with isotopic substitution of Li and reverse Monte Carlo modeling. Li atoms are found in distorted tetrahedral sites which are edge-linked with ${(\mathrm{S}\mathrm{i},\mathrm{A}\mathrm{l})\mathrm{O}}_{4}$ tetrahedra a…
The “living” free radical polymerization of styrene in the presence of 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) affords low polydispersity polystyrene (PS). The thermal instability of the linkage of the TEMPO group of the PS, however, restricts the processing possibilities of the resin. Therefore, different method…