Low-calcination temperatures of magnesia partially stabilized zirconia (Mg-PSZ) nanoparticles derived from local zirconium silicates

Abstract

Partially stabilized zirconia (PSZ) exhibits excellent physical, mechanical, electrical, chemical, thermal, and bioactive properties. Therefore, it is frequently used as a material for thermal barrier coatings, refractories, oxygen-permeating membranes, dental and bone implants. In this study, magnesia-partially stabilized zirconia nanoparticles were successfully prepared from zirconium silicates and MgSO4 assisted with PEG-6000 via a facile templating method. The MgO concentration was varied from 1%–10% in wt% of ZrO2. Zirconium silicates were initially converted to Zr-precursor solution, exhibiting pH 3. Then, the appropriate amount of the Mg-precursor was mixed with the proper amount of the Zr-precursor solution. A 10%(w/v) PEG-6000 solution was added into the PSZ precursor solution at a ratio of the precursor-to-PEG volumes of about 15:1 under stirring and heating, resulting in a very fine white gel. The gel was filtered, dried, and then calcined at elevated temperatures of 600, 800, and 1000 °C. The characteristics of the final product were then evaluated. According to the experimental results, the MgO concentration influences the ZrO2 phase transformation at elevated calcination temperatures. In this study, the lower the MgO dopant concentration added into ZrO2, the more stable the t- ZrO2 phase in PSZ samples at high temperatures. However, the MgO presence is detected as periclase in all samples with a very low peak intensity at elevated calcination temperatures. The obtained PSZ samples consist of nanoparticles and high agglomeration, some of particles exhibit elongated and rod-like shapes. The PEG existence during the PSZ preparation has restrained particle interaction and aggregation of the as-synthesized PSZ samples, leading to PSZ nanoparticles evolution.

Evaluation of Structural Stability, Mechanical Properties, and Corrosion Resistance of Magnesia Partially Stabilized Zirconia (Mg-PSZ)

“…Zirconia (zirconium dioxide, ZrO 2 ), also referred to as “ceramic steel”, has optimal properties for the use of dental implants due to its superior toughness, strength and resistance, excellent wear properties, and biocompatibility [ 1 , 2 , 3 ]. Amongst the commonly used materials in dentistry, zirconia has the advantage of being compatible for osteoblasts to adhere and proliferate [ 4 ].…”

“…At room temperature, ZrO 2 is in the form of a monoclinic phase, whereas to obtain the tetragonal and cubic phases requires a sintering temperature [ 11 ]. However, in several syntheses using lower calcination temperatures, tetragonal and cubic phases of ZrO 2 were obtained [ 1 , 12 ].…”

“…When compared with Y-PSZ, magnesium-stabilized zirconia (Mg-PSZ) shows promising characteristics in several aspects, including good mechanical and thermal properties, good stability in low temperature degradation (LTD), and the same coefficient of thermal expansion as YSZ [ 16 , 17 , 18 ]. Therefore, Mg-PSZ composite has the potential as a dental implant application material at a relatively low price [ 1 ].…”

“…In previous studies, t -ZrO 2 was successfully stabilized by adding MgO as a stabilizer and using a low calcination temperature of 800 °C to produce Mg-PSZ. The use of MgO as much as 1, 5, and 10% w/w succeeded in stabilizing ZrO 2 in tetragonal and cubic forms at room temperature [ 1 ]. In addition to stabilizing the tetragonal zirconia phase, the addition of 25% MgO concentration increased the hardness (Vickers) of ZrO 2 from 554 to 6350 MPa and fracture strength from 5.2 to 25 MPa.…”

“…During calcination, organic substances are burned as gas, leaving the particles in the nanostructures [ 14 ]. This phenomenon reduces the aggregation of synthesized Mg-PSZ particles, so that, in previous studies, Mg-PSZ was obtained with a nano-sized particle diameter of 9–44 nm [ 1 ].…”