Characteristic, Electrical and Optical Properties of Potassium Borate (KB5O8·4H2O) Hydrothermally Synthesised from Different Boron Sources

Potassium borate was hydrothermally synthesized from various of boron minerals (H3BO3, B2O3, Na2B4O7·5H2O and Na2B4O7·10H2O) at reaction conditions of 90 − 60°C and 120 − 15 min. The synthesised potassium borate was identified as “Santite (KB5O8·4H2O)” in X-Ray diffraction (XRD) analyses results. The specific band values between B and O atoms were characterized by Fourier transform infrared and Raman Spectroscopies. Multiangular particles were generally observed in the range of 234.94 nm − 3.41 µm. The use of different boron sources may affect the morphology. Higher reaction yields were determined in the use of boric acid (H3BO3). Optical absorption of potassium borate minerals was approximately 340 nm. AC and DC electrical properties of materials were determined by using current-voltage and capacitance voltage characteristics. Electrical resistivities of DC were found in the range of 4.17×108 – 4.07×1010 Ω.cm, whereas dielectric constants of AC were between 2×105 and 2×106.

A new rapid synthesis of potassium borates by microwave irradiation

Potassium borates are one of the minor groups of boron minerals with its distinct non-linear optical properties. In this study, potassium borate compound of santite (KB5O8·4H2O) are synthesized using potassium carbonate (K2CO3) and boric acid (H3BO3) with a new and rapid method of microwave irradiation. The synthesized minerals are characterized by various analysis techniques of X-ray diffraction (XRD), Raman spectroscopy and scanning electron microscope (SEM). Three parameters of “microwave power level”, “reaction times” and “reaction stoichiometric constants (elemental potassium to boron ratios)” are determined for the optimum synthesis of potassium borate within the four step. At the end of the step 4, optimum products are obtained as santite type potassium borate. Synthesized potassium borates Raman bands are in mutual agreement with the boron compounds and the overall reaction yields to potassium borates are very high compared with the lower reaction times.

Strong Effect of Process Parameters on the Properties of Boron-Containing Phenolic Resins with High Char Yield

This work is focused on the optimization of critical process parameters for preparation of boron-containing phenolic resin (B-containing PR), including the molar ratios of formaldehyde/phenol and potassium borate/phenol, reaction time; and measurement of surface tension of B-containing PR solution and wettability between B-containing PR solution and carbon fibers. The effects of the formaldehyde/phenol and potassium borate/phenol molar ratios on the char yield of the B-containing PR was studied. The highest char yield of B-containing PR could be as high as 71% under optimal conditions (molar ratios of formaldehyde/phenol = 1.8 and potassium borate/phenol = 0.2, and reaction time = 13 h). The effect of concentration and tested temperature on the surface tension of B-containing PR solution was investigated, and the wettability between B-containing PR solution and carbon fibers was evaluated for the first time, providing useful theory and experimental data for the preparation of B-containing PR-based composites.

An in situ anion exchange induced high-performance oxygen evolution reaction catalyst for the pH-near-neutral potassium borate electrolyte

A high-performance NiFe LDH oxygen evolution reaction catalyst for the pH-near-neutral potassium borate electrolyte obtained by an in situ anion exchange process.

The Effect of Heat Treatment on the Optical Properties of Copper-Containing Lithium-Potassium-Borate Glasses

The paper presents the investigation of lithium-potassium-alumoborate glasses (0- 25 mol.% Li2O) doped by copper ions. The effect of glass annealing on the Raman scattering patterns is discussed. It is shown that such an annealing results in drastic changes in the Raman scattering patterns for the glass with 10 mol.%of Li2O: the band at 481 cm-1 conventionally attributed to boron-oxygen bonds in metaborate rings disappears, while a set of narrow bands at 1236, 1500, and 1783 cm-1 is observed. We consider one of these bands, 1783 cm-1, as being the identifier of the formed Li(Al7B4O17) nanophase, XRD analysis supported the above suggestion. The effect of newly formed nanophase on the luminescence spectra is discussed.