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- Biofuels (3)
- Polyethylene grades (3)
- Change in MFR and tensile properties (2)
- Coating (2)
- Compatibility (2)
- NO2 (2)
- Ringversuch (2)
- Spurenverunreinigungen (2)
- ATR-FTIR (1)
- Al2O3 (1)
Organisationseinheit der BAM
- 1 Analytische Chemie; Referenzmaterialien (2)
- 1.4 Prozessanalytik (2)
- 3 Gefahrgutumschließungen; Energiespeicher (1)
- 3.2 Gefahrguttanks und Unfallmechanik (1)
- 4 Material und Umwelt (1)
- 4.5 Kunst- und Kulturgutanalyse (1)
- 5 Werkstofftechnik (1)
- 5.6 Glas (1)
- 7 Bauwerkssicherheit (1)
- 7.6 Korrosion und Korrosionsschutz (1)
IR and Raman study of calcium aluminosilicate glasses of the composition xCaO.xAl2O3.(100-2x)SiO2
(2002)
Resistance to oxidative degradation by nitric acid has been selected for a comparison of polyethylene grades in a European standard on suitability proof for alternative plastic resins used for packagings and intermediate bulk containers (IBCs) for the transport of dangerous goods. Measurements of the infrared (IR) absorption spectra of microtome slices cut from the walls of jerricans, which were pre-stored with 55% nitric acid for 21 and 42 days at 40°C, showed changes in the structure of the polyethylene. The penetration depths of 55% nitric acid into the polyethylene grades are, in principle, suitable for evaluating the resistance to oxidative degradation of polyethylene grades after pre-storage of the packagings for 21 days. After this period the packaging wall is not fully penetrated. The intensities of the IR bands at 1565 cm-1 (-NO2), 1630 cm-1 (-C=C) and 1654 cm-1 (-O-NO2) increased with the treatment time with 55% nitric acid as a result of oxidative damage by the nitric acid. The high increase in absorbance of the -C=C band in the region 1630 - 1690 cm-1 is attributable to paraffinic chain cracks. The absorbance of the -O-NO2 band, formed as result of the nitration process was still low at a test temperature of 40°C.
The suitability of an Al2O3 coating for corrosion protection on X20Cr13 was evaluated in various artificial geothermal brines, focusing on the influence of different pH (4, 6 and 8) and their chemical compositions on the coating properties. All experiments were performed in the laboratory using autoclaves at 150 ◦C and 1 MPa in deaerated condition for 1 and 7 days. Results showed that the pH of geothermal waters is the most detrimental factor in the transformation of ɣ-Al2O3 and its protective abilities. Delaminations were found in the Coating exposed to geothermal brines with pH 4. FTIR spectra indicated a transformation of ɣ-Al2O3 to boehmite AlOOH after exposure to pH 4 and 6, and bayerite Al(OH)3 was formed after exposure to pH 8. Different Crystal structures of the hydrated Al2O3 also contribute to the stability of the coatings, observed by the SEM- EDX of the surface and cross-section of coatings. This study indicated that ɣ-Al2O3 sol-gel coating presents a promising aspect of corrosion protection in geothermal environment with a neutral pH.
Improved wetting of bare and pre-coated steels by aqueous alumina sols for optimum coating success
(2010)
Alumina coatings are a promising candidate for
the protection of metals prone to high temperature corrosion.
If applied via sol–gel process, especially by using so
called aqueous modified Yoldas-sols, the deposition is
hardened by differences in surface free energy of substrate
and sol. In this paper the apparent surface properties of
samples to be coated and sols were examined by contact
angle measurements, IR-spectroscopy and tensiometry.
The results imply, after consideration of possible uncertainties,
the use of surface tension reducing 2-butanol
already present during hydrolysis of the sols to obtain an
easy and successful coating process.
Inorganic phosphorus and nitrogen-phosphorus-potassium (NPK) fertilizers based on phosphates from thermochemically treated sewage sludge ash were analyzed using mid-infrared (mid-IR) and far-infrared (FIR) spectroscopy. The different compounds present in the fertilizers were qualitatively determined with the help of recorded reference spectra of pure substances. Differentiation between various phosphates and other compounds such as sulfates, nitrates, and oxides was possible using combined interpretation of the mid-IR and FIR spectra. The results are in agreement with previous X-ray diffraction (XRD) measurements of the same samples. The main phosphate phases detected were NH4H2PO4, MgHPO4·3H2O, Mg3(PO4)2, Ca5(PO4)5Cl, CaHPO4·2H2O, Ca(H2-PO4)2·H2O, and AlPO4. Furthermore, K2SO4, NH4NO3, Fe2O3, and SiO2 were identified in the IR spectra. However, ammonium and sulfate compounds were only identified in the mid-IR region but were not detectable in the FIR region.
8iofuels including ethanol and biodiesel (fatty acid methyl ester) represent an important renewable fuel alternative to petroleum-derived transport fuels. lncreasing biofuels use would bring some benefits, such as a reduction in oil demands and greenhause gas emissions, and an improvement in air quality.