Effect of Nano-Al2O3 on the Microstructure and Properties of ZrO2 Dental Materials Prepared by Microwave Sintering

2014 ◽  
Vol 618 ◽  
pp. 3-7 ◽  
Author(s):  
Yun Long Ai ◽  
Xiang Hua Xie ◽  
Wen He ◽  
Bing Liang Liang ◽  
Wei Hua Chen
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Bending Strength ◽  
Microwave Sintering ◽  
Dental Materials ◽  
Transgranular Fracture ◽  
Composite Ceramics ◽  
Obvious Effect ◽  
Size Uniformity ◽  
Mutual Relations

Al2O3(x)/ZrO2composite ceramics were successfully prepared by microwave sintering. The influence of variety content of nanoAl2O3on mechanical properties and microstructure of ZrO2dental materials were studied, and analysied the mutual relations of chemical composition, mechanical properties and microstructure to investigate the reason of strengthening and toughening. Results indicated that The relative density of the Al2O3(x)/ZrO2composite ceramics reached more than 96.8%.The HV hardness ,bending strength and fracture toughness presented excellent mechanical properties as 12.5GPa, 753.8MPa and 11.8MPa·m1/2with the content of nanoAl2O3was 7.5%. Compared with that of pure ZrO2ceramics, the bending strength and the fracture toughness were improved 19% and 96%, respectively. The main crystal phases in this composite ceramics were t-ZrO2and α-Al2O3.The nanoAl2O3have a obvious effect on the strength and toughness of ZrO2based ceramics. The reason of strengthening and toughening mainly the additions reduced the ZrO2grains growth and promoted grains size uniformity, and changed the fracture mode from transgranular fracture to intergranular fracture characteristics.

scholarly journals Effect of Additive Ti3SiC2 Content on Mechanical Properties of B4C–TiB2 Composites Ceramics Sintered by Spark Plasma Sintering

2020 ◽  
Author(s):  
Xingheng Yan ◽  
Xingui Zhou ◽  
Honglei Wang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Spark Plasma Sintering ◽  
Bending Strength ◽  
High Fracture Toughness ◽  
Transgranular Fracture ◽  
Composite Ceramics ◽  
High Fracture ◽  
Plasma Sintering ◽  
Spark Plasma

Abstract B4C-TiB2 composite ceramics with ultra-high fracture toughness were successfully prepared via spark plasma sintering at 1900℃ using B4C and Ti3SiC2 as raw materials. The results show that compared with pure B4C ceramics sintered by SPS, the hardness of B4C-TiB2 composite ceramics is decreased, but the flexural strength and fracture toughness are significantly improved, especially the fracture toughness has been improved by leaps and bounds. When the content of Ti3SiC2 is 30vol.%, the B4C-TiB2 composite ceramic has the best comprehensive mechanical properties: hardness, bending strength and fracture toughness are 27.28 GPa, 405.11 MPa and 18.94 MPa·m1/2, respectively. The fracture mode of the B4C-TiB2 composite ceramics is a mixture of transgranular fracture and intergranular fracture. Two main two reasons for the ultra-high fracture toughness are the existence of lamellar graphite at the grain boundary, and the formation of a three-dimensional interpenetrating network covering the whole composite.

scholarly journals Effect of Additive Ti3SiC2 Content on the Mechanical Properties of B4C–TiB2 Composites Ceramics Sintered by Spark Plasma Sintering

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4616
Author(s):  
Xingheng Yan ◽  
Xingui Zhou ◽  
Honglei Wang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Spark Plasma Sintering ◽  
Bending Strength ◽  
High Fracture Toughness ◽  
Transgranular Fracture ◽  
Composite Ceramics ◽  
High Fracture ◽  
Plasma Sintering ◽  
Spark Plasma

B4C–TiB2 composite ceramics with ultra-high fracture toughness were successfully prepared via spark plasma sintering (SPS) at 1900 °C using B4C and Ti3SiC2 as raw materials. The results showed that compared with pure B4C ceramics sintered by SPS, the hardness of B4C–TiB2 composite ceramics was decreased, but the flexural strength and fracture toughness were significantly improved; the fracture toughness especially was greatly improved. When the content of Ti3SiC2 was 30 vol.%, the B4C–TiB2 composite ceramic had the best comprehensive mechanical properties: hardness, bending strength and fracture toughness were 27.28 GPa, 405.11 MPa and 18.94 MPa·m1/2, respectively. The fracture mode of the B4C–TiB2 composite ceramics was a mixture of transgranular fracture and intergranular fracture. Two main reasons for the ultra-high fracture toughness were the existence of lamellar graphite at the grain boundary, and the formation of a three-dimensional interpenetrating network covering the whole composite.

Effects of Nb2O5/La2O3 Synergistic Modification on Phase Composition, Microstructure and Mechanical Properties of Al2O3 Ceramics Prepared by Microwave Sintering

2014 ◽  
Vol 633 ◽  
pp. 49-52
Author(s):  
Yun Long Ai ◽  
Kai Wu ◽  
Xiang Hua Xie ◽  
Bing Liang Liang ◽  
Wen He ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Phase Composition ◽  
Bending Strength ◽  
Microwave Sintering ◽  
Composite Ceramic ◽  
Composite Ceramics ◽  
Comprehensive Properties ◽  
Microstructure And Mechanical Properties

Nb2O5-7.5La2O3-Al2O3 composite ceramics were prepared by microwave sintering. The influence of Nb2O5 and La2O3 proportion on the microstructure and mechanical properties of Al2O3 ceramics was investigated. The results show that when the Nb2O5 content was lower than La2O3, the columnar LaAl11O18 grains were generated by the reaction of La2O3 with Al2O3. When the Nb2O5 content was higher than La2O3, the surplus Nb2O5 induced the formation of columnar Al2O3 grains. The growth of columnar Al2O3 grains were promoted synergistically by LaNbO4 formed in-situ and Nb2O5. The 5Nb2O5-7.5La2O3-Al2O3 composite ceramic exhibited excellent comprehensive properties: ρr=99.3% (relative density), HV=11.2GPa (microhardness), KIC= 6.4MPa·m1/2 (fracture toughness), σ=304.3MPa (bending strength).

Microstructure and Properties of Al2O3-ZrO2 Ceramics Prepared by Microwave Sintering

2014 ◽  
Vol 633 ◽  
pp. 193-197 ◽  
Author(s):  
Yun Long Ai ◽  
Xiang Hua Xie ◽  
Wen He ◽  
Bing Liang Liang ◽  
Wei Hua Chen
Keyword(s):  
Mechanical Properties ◽  
Intergranular Fracture ◽  
Fracture Mode ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Microwave Sintering ◽  
Transgranular Fracture ◽  
Submicron Scale ◽  
Main Fracture ◽  
Sintering Processes

ZrO2 doped with 7.5% (volume percent) nanoalumina ceramics were prepared by microwave sintering processes. The effects of nanoalumina additions and various sintering temperature on densification, phase composition, microstructure and mechanical properties of Al2O3-ZrO2 ceramics were investigated. The results show that the m-ZrO2 phase transformed into t-ZrO2 during the process of microwave sintering. Relative densities between 95% and 99% were attained in the different conditions. In any cases the grain size was maintained at a submicron scale at a processing microwave sintering. The presence of Al2O3 grains had an effect of hindering grain growth of ZrO2 grains. When the microwave sintering temperature was 1500°C, 7.5Al2O3-ZrO2 composite ceramics presented excellent mechanical properties: HV=12.0 GPa, σf=715.7 Mpa, KIC=11.9 MPa·m1/2. Compared with that of pure ZrO2 ceramic, the bending strength and the fracture toughness were improved 45% and 23% at least, respectively. The fracture mode was associated with sintering temperature: when the sintering temperature was 1350°C~1450°C, the intergranular fracture and transgranular fracture coexisted; when the sintering temperature was 1500°C, intergranular fracture was the main fracture mode.

Mechanical Properties of α- and β-SiAlON Composite Ceramics Using β-SiAlON Powder

2008 ◽  
Vol 403 ◽  
pp. 111-114 ◽  
Author(s):  
Kei Asakoshi ◽  
Junichi Tatami ◽  
Katsutoshi Komeya ◽  
Takeshi Meguro ◽  
Masahiro Yokouchi
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Rare Earth ◽  
Chemical Composition ◽  
Metal Oxides ◽  
Bending Strength ◽  
Rare Earth Oxide ◽  
Composite Ceramics ◽  
Oxide Powders ◽  
Sialon Powder

β-SiAlON powder was used as a raw powder to fabricate α/β-SiAlON composite ceramics with different rare earth elements. The phases present in the sample fabricated from -SiAlON, α-Si3N4, AlN, and rare earth oxide powders were - and -SiAlONs. The composition was dependent on the chemical composition and firing profile. The sample obtained by adding Yb2O3 had a high -SiAlON content. The /-SiAlON composite ceramics had high densit. Their microstructures depended on the used metal oxides, namely, the addition of Nd2O3 and CaCO3 resulted in the elongation of the -SiAlON grains. The bending strength, fracture toughness, and hardness were influenced by the -SiAlON content, amount of elongated grains, and density of the sample.

Microstructure and Properties of Al2O3-ZrO2(n) Composite Ceramics Prepared by Microwave Sintering

2010 ◽  
Vol 177 ◽  
pp. 364-368
Author(s):  
Wen He ◽  
Yun Long Ai ◽  
Chang Hong Liu ◽  
Jian Ping Zhang ◽  
Jia Yuan Ding
Keyword(s):  
Fracture Toughness ◽  
Wear Resistance ◽  
Bending Strength ◽  
Phase Transfer ◽  
Microwave Sintering ◽  
Abrasive Particle ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Composite Ceramics ◽  
Alumina Matrix

Al2O3-ZrO2(n) composite ceramics were prepared by microwave sintering. The properties and microstructure were investigated, including vickers hardness, fracture toughness, bending strength, wear resistance and heat-shocking resistance. The results show that the properties and microstructure of alumina matrix ceramics are affected by the addition of nano-ZrO2 particles. When the content of ZrO2 is 15vol%, the hardness, fracture toughness and bending strength of the Al2O3-ZrO2 composites reach maximum values 13350MPa, 6.41MPa•m1/2 and 502MPa, respectively. The wear resistance of alumina matrix ceramics are improved only on the condition of adding an appropriate amount of nano-ZrO2. The wear mechanism of the composites are abrasive particle wear and adhesion wear co-existing. The crack propagation rate of Al2O3 matrix ceramics decreases remarkably with the addition of nano-ZrO2 particles. The mechanisms of ZrO2 improving the heat-shocking resistance of alumina matrix ceramics are mainly phase transfer toughening. Nano-ZrO2 particles exist in the intragranular and grain boundary of alumina matrix ceramics, and exist intragranular structures.

Effect of Sintering Pressure on Mechanical Properties of BN-Si3N4 Ceramic Composites Prepared by Spark Plasma Sintering

2016 ◽  
Vol 697 ◽  
pp. 188-192
Author(s):  
Jia Xin An ◽  
Wen Dong Xue ◽  
Feng Rui Zhai ◽  
Ruo Meng Xu ◽  
Jia Lin Sun
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Relative Density ◽  
Spark Plasma Sintering ◽  
Bending Strength ◽  
Raw Materials ◽  
Ceramic Composites ◽  
Composite Ceramics ◽  
Plasma Sintering ◽  
Spark Plasma

BN-Si3N4 composite ceramic wave-transparent materials with excellent mechanical properties were prepared by spark plasma sintering (SPS) using h-BN and α-Si3N4 powders as raw materials, Al2O3 and Y2O3 as sintering aids. The influence of sintering pressure on density and mechanical properties of BN-Si3N4 composite ceramics were studied. The phases were observed by X-ray diffraction (XRD), and the microstructures were identified by scanning electron microscopy (SEM). The results showed that with the sintering pressure increases, the relative density, bending strength and fracture toughness of the composite ceramics were significantly increased, and the porosity decreased rapidly. The effects of pressure on the properties of the composite ceramics was not significant at >40MPa, so 40MPa is optimal for the composite ceramics to gain good overall performance, i.e. the relative density was 89.1%, the porosity was 2.3%, the bending strength reached 215.4 MPa, and the fracture toughness was 3.1/MPa·m1/2.

Microstructure and Properties of Microwave Sintered 40 wt. % WC Steel-Bonded Carbides

2011 ◽  
Vol 335-336 ◽  
pp. 836-840 ◽  
Author(s):  
Jun Ming Luo ◽  
Zheng Wei ◽  
Ji Lin Xu ◽  
Li Ping Deng
Keyword(s):  
Mechanical Properties ◽  
Phase Transition ◽  
Bending Strength ◽  
Microwave Sintering ◽  
Strengthening Mechanism ◽  
Sintering Behavior ◽  
Transgranular Fracture ◽  
Strengthening Effect ◽  
Steel Matrix ◽  
Conventional Sintering

40 wt. %WC steel-bonded carbides were prepared by microwave sintering. The sintering behavior and mechanical properties of 40 wt. %WC-Fe were investigated in comparison with 0 wt. %WC-Fe. The green compact of 40 wt. %WC-Fe sintered at 1280 °C, the phase transition between WC and Fe is observed, generating new Fe2W2C phase. The phase transition promotes the densification of the sample, which plays a strengthening effect on the material. Microwave sintering possesses even quicker densification than conventional sintering, as well as substantially higher mechanical properties. The microhardness and bending strength of steel-bonded carbides prepared by microwave sintering are 10% ~ 20% higher than the conventional sintering. The microhardness of 40 wt. %WC-Fe is up to 544 HV, eight times higher than that of 0 wt. %WC-Fe and the bending strength of 40 wt. %WC-Fe is three times higher than that of 0 wt. %WC-Fe. Strengthening mechanism of 40 wt. %WC-Fe samples is that the Fe2W2C rigid phase dispersed over the steel matrix is not deformation, and plays the effect of hindering dislocation motion. The fracture mode is mixed intergranular fracture and transgranular fracture, belonging to brittle fracture.

Effects of Calcium Hexaluminate Addition on the Mechanical Properties of Zirconia-Toughened-Alumina

2013 ◽  
Vol 544 ◽  
pp. 286-290 ◽  
Author(s):  
Mei Ling Hu ◽  
Ming Hao Fang ◽  
Shu Sen Chen ◽  
Tao Yang ◽  
Zhao Hui Huang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Bending Strength ◽  
Alumina Ceramic ◽  
Pressureless Sintering ◽  
Composite Ceramics ◽  
Microstructure And Mechanical Properties ◽  
Calcium Hexaluminate ◽  
Zirconia Toughened Alumina

The effects of calcium hexaluminate addition on the microstructure and mechanical properties of zirconia-toughened-alumina ceramic were investigated. Zirconia-toughened-alumina (ZTA) composite ceramics which have different additions of calcium hexaluminate were successfully fabricated by pressureless sintering at 1600°C for 3h. The result shows that the bending strength and abrasive wearing improved with the increasing of CaAl12O19addition while the fracture toughness declined.

In Situ Preparation and Mechanical Properties of (ZrB2+ZrC)/Zr3[Al(Si)]4C6 Composites

2014 ◽  
Vol 602-603 ◽  
pp. 438-442
Author(s):  
Lei Yu ◽  
Jian Yang ◽  
Tai Qiu
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Bending Strength ◽  
Coefficient Of Thermal Expansion ◽  
Raw Materials ◽  
Linear Increase ◽  
Fine Grain ◽  
Fine Grain Strengthening ◽  
Uniform Microstructure

Fully dense (ZrB2+ZrC)/Zr3[Al (Si)]4C6 composites with ZrB2 content varying from 0 to 15 vol.% and fixed ZrC content of 10 vol.% were successfully prepared by in situ hot-pressing in Ar atmosphere using ZrH2, Al, Si, C and B4C as raw materials. With the increase of ZrB2 content, both the bending strength and fracture toughness of the composites increase and then decrease. The synergistic action of ZrB2 and ZrC as reinforcements shows significant strengthening and toughing effect to the Zr3[Al (Si)]4C6 matrix. The composite with 10 vol.% ZrB2 shows the optimal mechanical properties: 516 MPa for bending strength and 6.52 MPa·m1/2 for fracture toughness. With the increase of ZrB2 content, the Vickers hardness of the composites shows a near-linear increase from 15.3 GPa to 16.7 GPa. The strengthening and toughening effect can be ascribed to the unique mechanical properties of ZrB2 and ZrC reinforcements, the differences in coefficient of thermal expansion and modulus between them and Zr3[Al (Si)]4C6 matrix, fine grain strengthening and uniform microstructure derived by the in situ synthesis reaction.

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