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.

Abstract. Utilization of waste glass in cement is an attractive options because of its pozzolanic behaviour and the market of glass-composite cement is potentially available. The objective of this research is to evaluate the formulation of waste glass as supplementary cementitious material (SCM) by an extreme vertices mixture experiment, in which clinker, waste glass and gypsum proportions are chosen as experimental variables. The composite cements were synthesized by mixing all of powder materials in jar mill. The compressive strength of the composite cement mortars after being cured for 28 days ranges between 229 to 268 kg/cm2. Composite cement mortars exhibit lower compressive strength than ordinary Portland cement (OPC) mortars but is still capable of meeting the SNI 15-7064-2004 standards. The highest compressive strength is obtained by shifting the cement blend composition to the direction of increasing clinker and gypsum proportions as well as reducing glass proportion. The lower compressive strength of composite cement is caused by expansion due to ettringite and ASR gel. Based on the experimental result, the composite cement containing 80% clinker, 15% glass and 5% gypsum has the highest compressive strength. As such, the preliminary technical feasibility of reuse of waste glass as SCM has been confirmed.

elah dilaksanakan penelitian tentang sifat densitas dan kemagnetan bahan keramik barium ferit dari partikel nano BaFe 12 O 19 yang disiapkan menggunakan metode emulsi mikro. Metode ini meliputi: proses pembuatan emulsi, mixing, aging, sentrifus, drying, grinding, dan kalsinasi (suhu 900 o C). Selanjutnya partikel nano hasil kalsinasi dikompaksi induksi dengan tekanan 300 kg/cm 2. Bahan tersebut kemudian disinter pada suhu 1100 o C untuk mendapatkan keramik barium ferit. Indikasi terbentuknya partikel nano BaFe 12 O 19 telah dikonfirmasi menggunakan uji XRD dan TEM dengan ukuran partikel dibawah 100nm. Sifat keramik barium ferit yang dihasilkan dalam penelitian ini telah dibandingkan dengan sifat produk yang disiapkan menggunakan metode metalurgi serbuk. Hasil pengujian densitas mengindikasikan kerapatan lebih tinggi untuk keramik dari metode emulsi mikro (yakni 5,3 gr/ml). Hasil pengujian permagraf untuk induksi magnetik remanen 2,49 kOe dan produk energi maksimum 0,47 MGOe hal ini menunjukan nilai lebih sekitar 1,22x dan 1,47x dibanding keramik yang disiapkan dengan metode metalurgi serbuk.

No abstract