scholarly journals Analysis of the Electroconsolidation Process of Fine-Dispersed Structures Out of Hot Pressed Al2O3–WC Nanopowders

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6503
Author(s):  
Edwin Gevorkyan ◽  
Mirosław Rucki ◽  
Zbigniew Krzysiak ◽  
Volodymyr Chishkala ◽  
Wojciech Zurowski ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Tungsten Carbide ◽  
Sintering Temperature ◽  
Physical Processes ◽  
Heating Rates ◽  
Size Particle ◽  
Sintering Time ◽  
Maximal Load ◽  
High Heating ◽  
Nano Size

Fabrication of alumina–tungsten carbide nanocomposite was investigated. Characteristics of the densification and sintering were analyzed considering both the nano-size particle starting powders and the processing stages. Different heating rates were generated during densification and consolidation with a maximal load was applied only after a temperature of 1000 °C was reached. Due to the varying dominance of different physical processes affecting the grains, appropriate heating rates and pressure at different stages ensured that a structure with submicron grains was obtained. With directly applied alternating current, it was found that the proportion Al2O3 (50 wt.%)–WC provided the highest fracture toughness, and a sintering temperature above 1600 °C was found to be disadvantageous. High heating rates and a short sintering time enabled the process to be completed in 12 min, saving energy and time.

Effect of Sintering Conditions on Translucency of High Translucent Zirconia

2019 ◽  
Vol 829 ◽  
pp. 49-53
Author(s):  
Hiroshi Kono ◽  
Hiroyuki Arikawa ◽  
Syunichi Hamamura ◽  
Yasuhiro Sonoda ◽  
Masafumi Kikuchi
Keyword(s):  
Firing Temperature ◽  
Sintering Temperature ◽  
New Products ◽  
Contrast Ratio ◽  
Heating Time ◽  
Heating Rates ◽  
Sintering Time ◽  
Long Time ◽  
Sintering Conditions ◽  
Rising Time

Sintering of zirconia usually takes a long time. In recent years, new products with extremely short sintering time have been released. Therefore, it is useful to study in detail the effect of sintering temperature and time on translucency of zirconia. The prepared discs were sintered under four conditions; 30 minutes, 40 minutes, 50 minutes and 60 minutes as firing temperature rising time up to 1500°C. Samples were measured with a spectrophotometer and translucency parameter (TP), opalescence parameter (OP) and contrast ratio (CR) were calculated. In this study, there were no statistically significant differences between TP, OP and CR due to the differences in heating rates. There is a possibility that a heating time up to the sintering temperature does not affect translucency of zirconia.

Mechanical Properties of La2O3-Al2O3 Ceramics Prepared by Microwave Sintering

2012 ◽  
Vol 519 ◽  
pp. 265-268 ◽  
Author(s):  
Yun Long Ai ◽  
Fei He ◽  
Bing Liang Liang ◽  
Wen He ◽  
Wei Hua Chen
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Draw Ratio ◽  
Sintering Temperature ◽  
Microwave Sintering ◽  
Microwave Energy ◽  
Pure Alumina ◽  
Sintering Time ◽  
Microstructure Evaluation ◽  
Columnar Grains

The influence of La2O3 on the phase and microstructure evaluation and mechanical properties of La2O3-Al2O3 ceramics sintered with 2.45 GHz microwave energy was investigated. The results showed that La2O3 could densify the pure alumina with a lower sintering temperature and a short sintering time. La2O3 reacted with Al2O3 to form LaAl11O18 completely and the amount of LaAl11O18 increased with the increasing content of La2O3, distributing at the Al2O3 grain boundaries. The specimen doped with 10 vol.% and 15 vol.% La2O3 sintered at 1500 °C exhibited plenty of columnar grains with draw ratio about 1:4. The existence of columnar grains enhanced the microhardness and fracture toughness of La2O3-Al2O3 ceramics.

Influence of Hot Pressing Sintering Temperature and Time on Microstructure and Mechanical Properties of TiB2/Al2O3 Tool Materials

2012 ◽  
Vol 500 ◽  
pp. 629-633 ◽  
Author(s):  
Mei Lin Gu ◽  
Hong Jing Xu ◽  
Jian Hua Zhang ◽  
Zhi Wei
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Hot Pressing ◽  
Sintering Temperature ◽  
Three Point Bending ◽  
Sintering Time ◽  
Microstructure And Mechanical Properties ◽  
Hot Pressing Sintering ◽  
Increasing Temperature

In this paper, a TiB2/Al2O3composite was hot-pressed. The effect of hot pressing parameters on the TiB2/Al2O3composite microstructure and mechanical properties was investigated. The flexural strength and fracture toughness were measured by three point bending testing and direct indentation method, respectively. Experimental results show that the flexural strength decreases consistently with an increase in the sintering time, however, the fracture toughness increases consistently with an increase in the sintering time and sintering temperature. The maximum of the flexural strength is 1072 MPa at 1530 sintering temperature and 60 min sintering time. The microstructures were revealed by means of SEM. The results show that the TiB2grain size and density increases with the increasing temperature and time during hot pressing sintering, which benefits the fracture toughness and flexural strength.

Mechanical Properties and Microstructure of Al2O3/(W, Ti)C Nanocomposite

2008 ◽  
Vol 368-372 ◽  
pp. 717-720 ◽  
Author(s):  
Yong Hui Zhou ◽  
Xing Ai ◽  
Jun Zhao ◽  
Xun Liang Yuan ◽  
Qiang Xue
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Sintering Temperature ◽  
Crack Deflection ◽  
Nano Particles ◽  
Nano Scale ◽  
Sintering Time ◽  
Properties Of Materials ◽  
Al2o3 Matrix ◽  
Skeleton Structure

The Al2O3/(W, Ti)C nanocomposite was fabricated by hot pressing technique at 1650-1700°C under 30MPa for 10min. The fracture toughness remarkably increased by adding nano-scale Al2O3 (11vol %) particles into Al2O3 matrix. The flexural strength, fracture toughness and Vickers hardness are 840 MPa, 6.55 MPa•m1/ 2 and 20.1 GPa, respectively. The microstructure of the nanocomposite is homogenous skeleton structure. Nano particles could refine matrix grains and lead to the crack deflection as well as branching and bridging. The coexistence of nano-scale Al2O3, micro-scale Al2O3 and (W, Ti)C can reduce the sintering temperature and sintering time as well as the grain size, and improve the densification and mechanical properties of materials.

scholarly journals Study on high temperature sintering processes of selective laser sintered Al2O3/ZrO2/TiC ceramics

2009 ◽  
Vol 41 (1) ◽  
pp. 35-41 ◽  
Author(s):  
P. Bai ◽  
Y. Li
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
High Temperature ◽  
Mechanical Strength ◽  
Relative Density ◽  
Sintering Temperature ◽  
Sintering Time ◽  
Sintering Processes ◽  
Al2o3 Matrix

High temperature sintering processes of selective laser sintered Al2O3/ZrO2/TiC ceramics were studied. The effects of the sintering temperature and the sintering time on the relative density, strength and fracture toughness of Al2O3/ZrO2/TiC ceramics were investigated. The results showed that the sintering temperature and sintering time had a great effect on the relative density and the mechanical properties of Al2O3/ZrO2/TiC ceramics. The mechanical strength increased from 120MPa to 360MPa and KIC increased from 3.7 J/m2 to 6.9 J/m2 when the sintering temperature increased from 1400?C to 1600?C, however, the mechanical strength decreased rapidly from 370MPa to 330MPa and KIC decreased from 6.9 J/m2 to 6.1 J/m2 when the sintering time increased from 30min to 90min. Furthermore, the addition of TiC and ZrO2 in the Al2O3 matrix significantly improved mechanical strength and fracture toughness of the Al2O3 matrix ceramics.

Mechanical Properties of Nb2O5-Al2O3 Ceramics Prepared by Microwave Sintering

2011 ◽  
Vol 338 ◽  
pp. 120-123 ◽  
Author(s):  
Yun Long Ai ◽  
Fei He ◽  
Bing Liang Liang ◽  
Wen He ◽  
Wei Hua Chen
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Draw Ratio ◽  
Sintering Temperature ◽  
Microwave Sintering ◽  
Microwave Energy ◽  
Pure Alumina ◽  
Sintering Time ◽  
Microstructure Evaluation ◽  
Columnar Grains

The influence of Nb2O5 on the phase and microstructure evaluation and mechanical properties of Nb2O5-Al2O3 ceramics sintered with 2.45 GHz microwave energy was investigated. The results showed that Nb2O5 could densify the pure alumina with a lower sintering temperature and a short sintering time. Nb2O5 reacted with Al2O3 to form AlNbO4 completely and the amount of AlNbO4 increased with the increasing content of Nb2O5, distributing at the Al2O3 grain boundaries. The specimen doped with 10 vol.% Nb2O5 sintered at 1500 °C exhibited plenty of columnar grains with draw ratio about 1:3. The existence of columnar grains enhanced the microhardness and fracture toughness of Nb2O5-Al2O3 ceramics.

Comparing fast inductive tempering and conventional tempering: Effects on microstructure and mechanical properties

2018 ◽  
Vol 115 (4) ◽  
pp. 407 ◽  
Author(s):  
Annika Eggbauer Vieweg ◽  
Gerald Ressel ◽  
Peter Raninger ◽  
Petri Prevedel ◽  
Stefan Marsoner ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Impact Energy ◽  
Charpy Impact ◽  
Heat Treating ◽  
Processing Route ◽  
High Heating Rate ◽  
Heating Rates ◽  
High Heating ◽  
Tempering Treatment ◽  
Carbide Distribution

Induction heating processes are of rising interest within the heat treating industry. Using inductive tempering, a lot of production time can be saved compared to a conventional tempering treatment. However, it is not completely understood how fast inductive processes influence the quenched and tempered microstructure and the corresponding mechanical properties. The aim of this work is to highlight differences between inductive and conventional tempering processes and to suggest a possible processing route which results in optimized microstructures, as well as desirable mechanical properties. Therefore, the present work evaluates the influencing factors of high heating rates to tempering temperatures on the microstructure as well as hardness and Charpy impact energy. To this end, after quenching a 50CrMo4 steel three different induction tempering processes are carried out and the resulting properties are subsequently compared to a conventional tempering process. The results indicate that notch impact energy raises with increasing heating rates to tempering when realizing the same hardness of the samples. The positive effect of high heating rate on toughness is traced back to smaller carbide sizes, as well as smaller carbide spacing and more uniform carbide distribution over the sample.

scholarly journals Synthesis and Na+ Ion Conductivity of Stoichiometric Na3Zr2Si2PO12 by Liquid-Phase Sintering with NaPO3 Glass

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3790
Author(s):  
Yongzheng Ji ◽  
Tsuyoshi Honma ◽  
Takayuki Komatsu
Keyword(s):  
Solid State ◽  
Liquid Phase ◽  
Sintering Temperature ◽  
Liquid Phase Sintering ◽  
Ion Conductivity ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
X Ray ◽  
Sintering Time ◽  
Lower Activation

Sodium super ionic conductor (NASICON)-type Na3Zr2Si2PO12 (NZSP) with the advantages of the high ionic conductivity, stability and safety is one of the most famous solid-state electrolytes. NZSP, however, requires the high sintering temperature about 1200 °C and long sintering time in the conventional solid-state reaction (SSR) method. In this study, the liquid-phase sintering (LPS) method was applied to synthesize NZSP with the use of NaPO3 glass with a low glass transition temperature of 292 °C. The formation of NZSP was confirmed by X-ray diffraction analyses in the samples obtained by the LPS method for the mixture of Na2ZrSi2O7, ZrO2, and NaPO3 glass. The sample sintered at 1000 °C for 10 h exhibited a higher Na+ ion conductivity of 1.81 mS/cm at 100 °C and a lower activation energy of 0.18 eV compared with the samples prepared by the SSR method. It is proposed that a new LPE method is effective for the synthesis of NZSP and the NaPO3 glass has a great contribution to the Na+ diffusion at the grain boundaries.

scholarly journals Microwave Sintering and Microwave Dielectric Properties of (1–x)Ca0.61La0.26TiO3-xNd(Mg0.5Ti0.5)O3 Ceramics

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 438
Author(s):  
Shuwei Yang ◽  
Bingliang Liang ◽  
Changhong Liu ◽  
Jin Liu ◽  
Caisheng Fang ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Mobile Communications ◽  
Sintering Temperature ◽  
Microwave Sintering ◽  
Microwave Dielectric Properties ◽  
Conventional Heating ◽  
Sintering Process ◽  
Microwave Dielectric ◽  
Sintering Time ◽  
Frequency Temperature

The (1–x)Ca0.61La0.26TiO3-xNd(Mg0.5Ti0.5)O3 [(1–x)CLT-xNMT, x = 0.35~0.60] ceramics were prepared via microwave sintering. The effects of sintering temperature and composition on the phase formation, microstructure, and microwave dielectric properties were investigated. The results show that the microwave sintering process requires a lower sintering temperature and shorter sintering time of (1–x)CLT-xNMT ceramics than conventional heating methods. All of the (1–x)CLT-xNMT ceramics possess a single perovskite structure. With the increase of x, the dielectric constant (ε) shows a downward trend; the quality factor (Qf) drops first and then rises significantly; the resonance frequency temperature coefficient (τf) keeps decreasing. With excellent microwave dielectric properties (ε = 51.3, Qf = 13,852 GHz, τf = −1.9 × 10−6/°C), the 0.65CLT-0.35NMT ceramic can be applied to the field of mobile communications.

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