Irmina Kris Murwani

Synthesis and characterization of Zn doped magnesium hydroxyfluoride, Mg1−xZnxFOH

A series of Zn-Doped Magnesium Hydroxyfluoride, Mg1−xZnxFOH) samples with 0 to 0.15 of x were prepared using a sol–gel synthesis and dried with vacuum technique. XRD characterization of the samples indicated the amorphous phase of Mg1−xZnxFOH similarity with MgF2. The Zn doped in magnesium hydroxyfluoride did not affected on the basic structure of magnesium hydroxyfluoride. The FTIR spectra showed the samples had a broad band at 3000-3700 cm−1 and 1620 cm−1 was indicated of adsorbed H2O molecules and a bridging hydroxyl groups, respectively. The intensity of the 460, and 550 cm−1 bands correlates to Mg-F and Mg-O vibrations. The Zn-O stretching vibration of Zn-doped magnesium hydroxyfluoride appeared at 1634 and 621 cm−1.

Characterization of a series nickel doped magnesium hydroxyflouride Mg1−xNixFOH with XRD and FTIR

A series nickel doped magnesium hydroxyfluoride, Mg1−xNixFOH has been prepared by fluorolytic sol-gel method. The x values in these series were from 0 to 0,15. The samples structure was obtained as amorphous phase from XRD characterization. The XRD patterns showed any peaks like the mixing between magnesium fluoride (selllaite) and magnesium hydroxide (brucite). The IR spectra from FTIR characterization of Mg1−xNixFOH samples indicated the peaks of OH bridging at 3630-3000 cm−1, Ni-OH vibration around 660-650 cm−1 Mg-O vibration around 550 cm−1, and Mg-F vibration at 460 cm−1.

The influence of dicarboxylic acids: Oxalic acid and tartaric acid on the compressive strength of glass ionomer cements

Glass ionomer cement (GIC) has limitation on the mechanical properties especially compressive strength. The change of compressive strength of GIC by adding oxalic acid and tartaric acid has been investigated. Oxalic acid and tartaric acid was added to the liquid components at concentrations of 0 – 15% (w/w). Powder component of GIC was made from optimum experimental powder glass SiO2-Al2O3-CaF2. GIC was characterized by compressive strength test, SEM-EDX and FTIR. The addition of tartaric acid to GIC has greater improvement than addition of oxalic acid. The addition of tartaric acid at 10 % (w/w) to GIC has greatest value of compressive strength.