Papers by Keyword: Sintering Aid

Abstract: In this paper, the YAG powder is prepared by the co-precipitation method. In addition, the sintering aid to aid sintering and the high temperature foaming agent that becomes gas released during the heating process so that the sample has pores, the ball mill mixes the material, and the sample press is extruded. Box-type resistance furnace sintering. Through this process, porous ceramics can be made. Study the effect of sintering aid content, foaming agent type, sintering temperature on the properties of YAG porous materials. The analysis and discussion can lead to the following conclusions: as the content of sintering aid silica in the sample increases, the sintering temperature of the sample decreases. It is best when the ratio of sintering aid alumina to silica is 3:1. The moldability of the sample whose foaming agent is wood chips is worse than that of the sample whose foaming agent is fiber and carbon powder. The ratio of sintering aid alumina to silica is 3:1, and the sintering temperature of the sample with carbon powder as the blowing agent is best when the sintering temperature is 1400 °C.

Abstract: Three-dimensional (3D) carbonated hydroxyapatite (CHA) porous scaffolds were successfully fabricated via polyurethane (PU) replication technique. Two sets of porous CHA scaffolds were prepared using: 1) as-synthesized CHA slurry (SCHA) and (2) as-synthesized CHA slurry with the addition of sintering aid, magnesium hydroxide (SCHA+Mg (OH)₂). The aim of this study was to investigate the influences of the addition of sintering aid in the fabrication of porous CHA scaffolds in terms of phase purity, crystallinity, architecture, and mechanical properties. Result suggested that both of the fabricated porous scaffolds remained as single phase B-type CHA and free of secondary phases. Interestingly, the use of Mg (OH)₂ as sintering aid led to better internal architecture resulted in smoother surface and less micro-cracks/pores formation on the struts since the struts was found to be more densified as compared to SCHA scaffolds. In terms of mechanical properties, SCHA+ Mg (OH)₂ scaffolds showed higher compressive strength, indicating that the use of Mg (OH)₂ had successfully reduced the sintering temperature and improve the densification of porous scaffolds. Thus, SCHA+ Mg (OH)₂ scaffolds was found to be a better choice of scaffold with respect to its handling, compaction strength and architecture with improve strut properties.

Abstract: In this paper, the BaZrO₃(BZ) and BaZr_0.97Y_0.03O_3-δ (BZY3) powders were prepared by using the industrial grade BaCO₃, ZrO₂ and Y₂O₃ powders combining the conventional solid state reaction. The BaZrO₃(BZ) and BaZr_0.97Y_0.03O_3-δ (BZY3) ceramics were fabricated at 1750°C. The effect of ball milling time and sintering aid (TiO₂) on the sinterability of BaZr_0.97Y_0.03O_3-δ (BZY3) ceramics were investigated, and the improved stability of BaZrO₃ refractory with Y₂O₃ additive were studied according to the refractory-metal interaction. The results revealed that the particle size of BZY3 powders decreased first and then increased with the increasing of ball milling time from 6h to 12h, and the minimum particle size was only 2.252μm at 8h. When 2wt.%TiO₂ was added, the sintered pellet of BZY3 was the most densest and the relative density was above 95%. After melting the Ti₂Ni alloy on the BZY and BZ ceramics, the thickness erosion layer of BaZrO₃ and BZY₃ refractories and Ti₂Ni alloy is approximately 50μm and 20μm respectively, showing that BZY3 was more stable than BaZrO₃ refractory.

Abstract: CaF₂ inorganic nanometer powder particles were used as sintering aid to sintering good conductive Fe-6.5Si alloy. By a physical method, CaF₂ inorganic nanopowder particles were made with a granularity of 15-30 nm assembled between micron-sized Fe-6.5Si powder particles prepared by gas atomization. 6.5 % Si high silicon steel were fabricated by spark plasma sintering (SPS) with varying contents of CaF₂. The discharge enhancement effect of CaF₂ inorganic nanospark plasma aid is confirmed. The initial sintering temperature and the final sintering temperature were decreased by 75 °C and 70 °C respectively with 0.5 % CaF₂ inorganic nanopowder aid. In the case of reduced 60 °C, the higher density for the particles with the addition of CaF₂ was observed compared with without CaF₂. When the nanopowder was 2%, sintering performance decreased. The study indicates that sintering pressure has an enormous effect on the Fe-6.5Si sintering effect.

Abstract: (Ca_0.9Mg_0.1)SiO₃ ceramics possess a low dielectric constant and a high Qf value, however, the densification temperature of (Ca_0.9Mg_0.1)SiO₃ ceramics is higher than 1280°C. In this paper, the effect of Li₂CO₃ addition on sinterability and dielectric properties of (Ca_0.9Mg_0.1)SiO₃ ceramics were studied. The phase presence and surface morphology were determined by XRD and SEM techniques, respectively. CaSiO₃ and Ca₂MgSi₂O₇ phases were observed. With the addition of >2.0 wt% Li₂CO₃, the sintering temperature of (Ca_0.9Mg_0.1)SiO₃ ceramic was significantly lowered, reaching to 1070°C. (Ca_0.9Mg_0.1)SiO₃ ceramics with 4wt% Li₂CO₃ sintered at 1070°C for 3 h shows excellent dielectric properties: ε_r=5.91, Qf = 15300GHz (at 10GHz).

Abstract: The ceramics with large bulk density and high bending strength were fabricated via semi-dry pressing and pressureless sintering in the air. Andalusite and calcined bauxite were used as the raw materials, sintering aids such as potassium feldspar, albite, talc, spodumene and borax were added to promote the densification and decrease the sintering temperature of the samples. The best physical properties were obtained on a sample of optimal composition (the addition of sintering aid was talc) sintered at 1500 °C for 3 h, i.e. a bending strength of 138.52 MPa and bulk density of 2.61gcm^-3, the sintering temperature was lower than sample without addition of sintering aid.

Abstract: The Cu-deficient Cu(In,Ga)Se₂ (CIGSe) absorber layer for thin film solar cells was prepared by paste printing its powders followed by sintering at 550  650oC for 1 h with the assistance of sintering aid of 10% Te or 5% Sb₂S₃ to enhance densification. The variations of crystallinity, microstructure, composition, and electrical properties of resistivity, Hall mobility, and carrier concentration of CIGSe absorber layer with sintering temperature at different sintering aids were investigated. The advantage of this sintering process is the stability in composition and free of the problem of constituent vaporization. The major disadvantage of the CIGSe layer with 5% Sb₂S₃ as a sintering aid was a 5-time decrease in electrical mobility. Power conversion efficiencies of our devices with sintered CIGSe as an absorber layer were evaluated.

Abstract: TiAl alloy powder is difficult to sinter unless assisted with pressure and/or pulsed current. This paper investigates the effect of a small addition of iron on the sintering behaviour of γ-TiAl alloy powder at 1350 °C in vacuum. Thermodynamic calculations using Thermo-Calc and the Ti-alloy database TTTI3 predict that iron is a potential sintering aid for TiAl powder. The relative sintered density (RSD) increased with increasing Fe content and peaked at an addition of 2at.%Fe, at which the RSD increased from ~ 60% theoretical density (TD) without iron to ~ 97%TD. The enhanced densification is attributed to liquid formation induced by iron based on both thermodynamic predictions and differential scanning calorimetry (DSC) analysis. The as-sintered microstructures and phase constituents were analysed by scanning electron microscopy (SEM) equipped with an energy dispersive spectroscopy (EDS) microanalysis system and X-ray diffraction (XRD) analysis.

Abstract: Translucent β-Si₃N₄ sintered ceramics have been fabricated by using AlN-MgO sintering additives. In the present study, the authors employed AlN-MgO as a standard sintering aid, and investigated the effects of sintering conditions on the translucency of Si₃N₄. Furthermore, various oxides such as HfO₂, Sm₂O₃, Y₂O₃, Sc₂O₃, La₂O₃, Nd₂O₃, CeO₂, CaO, ZrO₂ etc. were used as the sintering aids of Si₃N₄, and the sintered β-Si₃N₄ ceramics exhibited different transmittances in the visible region. It was found that the transmittance of sintered ceramics was mainly affected by the sintering additives.

Abstract: The perovskite-type Ba(Zr_0.63Ce_0.27)Y_0.1O_3-δ (BZCY) was synthesized by solid-state reaction. Sintering behavior and electrical conductivity of the electrolyte materials were improved through optimizing the content of ZnO as sintering aid. The obvious enhancement of density of sintered body was observed due to ZnO reacting with BZCY powder. Relative densities of the samples increased with ZnO content added. A conductivity of 9.27×10^-3 S/cm tested in humid hydrogen at 800°C was obtained when the ZnO content was 2 mol%. A peak power density of 12.4 mW/cm² was delivered based on a single fuel cell with electrolyte-supported configuration.