Topic
Hydrofluoric acid
About: Hydrofluoric acid is a research topic. Over the lifetime, 5577 publications have been published within this topic receiving 51599 citations. The topic is also known as: Hydrofluoric acid.
Papers published on a yearly basis
Papers
More filters
TL;DR: In this article, the effect of treatment with 10% hydrofluoric acid on bulk chemical composition and resolution of solid-state 13C NMR spectra was investigated with six soils, some associated particle size fractions, plant litter and compost.
Abstract: Summary The small organic matter content of mineral soils makes it difficult to obtain I3C and 15N nuclear magnetic resonance (NMR) spectra with acceptable signal-to-noise ratios. Subjecting such samples to hydrofluoric acid removes mineral matter and leads to a relative increase in organic material. The effect of treatment with 10% hydrofluoric acid on bulk chemical composition and resolution of solid-state 13C NMR spectra was investigated with six soils, some associated particle size fractions, plant litter and compost. The treatment enhanced the signal-to-noise ratio of the solid-state I3C NMR spectra. The improvement in spectrum quality was greatest in the clay fraction of soil contaminated with coal ash. The removal of paramagnetic compounds associated with the ash may be the main reason for the improvement. Based on total C, total N, C/N ratio and intensity distribution of the solid-state I3C NMR spectra, no changes in organic matter composition could be detected, except for a possible loss of carbohydrates. After treatment with HF, solid-state I5N NMR spectra of particle size fractions were obtained and indicated that the observable nitrogen is present mostly as peptides and free amino groups. Extraction with hydrofluoric acid is recommended as a routine treatment prior to solid-state I3C and "N NMR on soil containing little C or N and soil samples containing paramagnetic compounds from natural or anthropogenic sources.
359 citations
TL;DR: The results of this study revealed a relation between the fluoride concentrations and pH values at which Ti corrosion occurred and provided data on such corrosion in environments where the fluoride concentration and pH value are known.
Abstract: Titanium is used as a metal for biocompatible materials such as dental implants or restorations because of its excellent chemical stability. However, the corrosion of Ti in the prophylactic fluoride-containing environment can become problematic. To clarify the effects of fluoride concentration and pH on the corrosion behavior of Ti, we conducted anodic polarization and immersion tests in NaF solution of various concentrations and pH values. The concentrations of dissolved Ti in the test solutions were analyzed by inductively coupled plasma mass spectroscopy. There were obvious limits of fluoride concentration and the pH value at which the corrosion behavior of Ti changed. The corrosion of Ti in the solution containing fluoride depended on the concentration of hydrofluoric acid (HF). When the HF concentration in the solution was higher than about 30 ppm, the passivation film of the Ti was destroyed. The results of this study revealed a relation between the fluoride concentrations and pH values at which Ti corrosion occurred and provided data on such corrosion in environments where the fluoride concentration and pH value are known.
302 citations
TL;DR: In this paper, the influence of particle size, time and temperature on the kinetics of the selective extraction of Al from the ternary layered transition metal carbide, Ti3AlC2, when powders of the latter are immersed in hydrofluoric acid.
282 citations
TL;DR: In this article, the anodic dissolution rate of silicon is investigated as a function of the electrode potential, the doping of the crystal and of the hydrofluoric acid concentration, and it is shown that at lower anodic electrode potentials two holes and at higher electrode potential four holes are consumed.
253 citations
TL;DR: In this paper, carbon nanotubes were prepared by thermal decomposition of acetylene over silica-supported cobalt catalysts, and they were analyzed by means of transmission electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy.
248 citations