scholarly journals New Perspectives on Zirconia Composites as Biomaterials

2021 ◽  
Vol 5 (9) ◽  
pp. 244
Author(s):  
Giuseppe Magnani ◽  
Paride Fabbri ◽  
Enrico Leoni ◽  
Elena Salernitano ◽  
Francesca Mazzanti
Keyword(s):  
Mechanical Properties ◽  
Dental Implants ◽  
High Performance ◽  
Bending Strength ◽  
Ceramic Powder ◽  
Orthopedic Implants ◽  
Forming Process ◽  
Digital Light Processing ◽  
Zirconia Composites ◽  
Alumina Composites

Zirconia–alumina composites couple the high toughness of zirconia with the peculiar properties of alumina, i.e., hardness, wear, and chemical resistance, so they are considered promising materials for orthopedic and dental implants. The design of high performance zirconia composites needs to consider different aspects, such as the type and amount of stabilizer and the sintering process, that affect the mechanics of toughening and, hence, the mechanical properties. In this study, several stabilizers (Y2O3, CuO, Ta2O5, and CeO2) were tested together with different sintering processes to analyze the in situ toughening mechanism induced by the tetragonal–monoclinic (t–m) transformation of zirconia. One of the most important outcomes is the comprehension of the opposite effect played by the grain size and the tetragonality of the zirconia lattice on mechanical properties, such as fracture toughness and bending strength. These results allow for the design of materials with customized properties and open new perspectives for the development of high-performance zirconia composites for orthopedic implants with high hydrothermal resistance. Moreover, a near-net shape forming process based on the additive manufacturing technology of digital light processing (DLP) was also studied to produce ceramic dental implants with a new type of resin–ceramic powder mixture. This represents a new frontier in the development of zirconia composites thanks to the possibility to obtain a customized component with limited consumption of material and reduced machining costs.

scholarly journals The Influence of Co Additive on the Sintering, Mechanical Properties, Cytocompatibility, and Digital Light Processing Based Stereolithography of 3Y-TZP-5Al2O3 Ceramics

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2789 ◽  
Author(s):  
Margarita Goldberg ◽  
Tatiana Obolkina ◽  
Sergey Smirnov ◽  
Pavel Protsenko ◽  
Dmitriy Titov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Ceramic Powder ◽  
Tetragonal Zirconia ◽  
Specific Area ◽  
Precipitation Method ◽  
Temperature Phase ◽  
Sintered Ceramic ◽  
Digital Light Processing

Nanocrystalline 3 mol% yttria-tetragonal zirconia polycrystal (3Y-TZP) ceramic powder containing 5 wt.% Al2O3 with 64 m2/g specific area was synthesized through precipitation method. Different amounts of Co (0–3 mol%) were introduced into synthesized powders, and ceramic materials were obtained by heat treatment in the air for 2 h at 1350–1550 °C. The influence of Co addition on the sintering temperature, phase composition, microstructure, mechanical and biomedical properties of the obtained composite materials, and on the resolution of the digital light processing (DLP) printed and sintered ceramic samples was investigated. The addition of a low amount of Co (0.33 mol%) allows us to decrease the sintering temperature, to improve the mechanical properties of ceramics, to preserve the nanoscale size of grains at 1350–1400 °C. The further increase of Co concentration resulted in the formation of both substitutional and interstitial sites in solid solution and appearance of CoAl2O4 confirmed by UV-visible spectroscopy, which stimulates grain growth. Due to the prevention of enlarging grains and to the formation of the dense microstructure in ceramic based on the tetragonal ZrO2 and Al2O3 with 0.33 mol% Co the bending strength of 720 ± 33 MPa was obtained after sintering at 1400 °C. The obtained materials demonstrated the absence of cytotoxicity and good cytocompatibility. The formation of blue CoAl2O4 allows us to improve the resolution of DLP based stereolithographic printed green bodies and sintered samples of the ceramics based on ZrO2-Al2O3. The developed materials and technology could be the basis for 3D manufacturing of bioceramic implants for medicine.

scholarly journals High performance hydroxyapatite ceramics and a triply periodic minimum surface structure fabricated by digital light processing 3D printing

2021 ◽  
Vol 10 (1) ◽  
pp. 39-48
Author(s):  
Yongxia Yao ◽  
Wei Qin ◽  
Bohang Xing ◽  
Na Sha ◽  
Ting Jiao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
High Performance ◽  
Bending Strength ◽  
Digital Light Processing ◽  
Sintering Atmosphere ◽  
Minimum Surface ◽  
Cell Vitality ◽  
Triply Periodic ◽  
Hydroxyapatite Ceramics

AbstractHigh performance hydroxyapatite (HA) ceramics with excellent densification and mechanical properties were successfully fabricated by digital light processing (DLP) three-dimensional (3D) printing technology. It was found that the sintering atmosphere of wet CO2 can dramatically improve the densification process and thus lead to better mechanical properties. HA ceramics with a relative density of 97.12% and a three-point bending strength of 92.4 MPa can be achieved at a sintering temperature of 1300 , which makes a solid foundation for application ℃ in bone engineering. Furthermore, a relatively high compressive strength of 4.09 MPa can be also achieved for a DLP-printed p-cell triply periodic minimum surface (TPMS) structure with a porosity of 74%, which meets the requirement of cancellous bone substitutes. A further cell proliferation test demonstrated that the sintering atmosphere of wet CO2 led to improve cell vitality after 7 days of cell culture Moreover, with the possible benefit from the bio-inspired structure, the 3D-printed TPMS structure significantly improved the cell vitality, which is crucial for early osteogenesis and osteointegration.

Mechanical Properties of Zirconia Toughened Alumina Composites with TZP Partially Nanostructured Sintered by Liquid Fase

2008 ◽  
Vol 591-593 ◽  
pp. 436-440
Author(s):  
João Marcos K. Assis ◽  
Francisco Piorino Neto ◽  
Francisco Cristóvão Lourenço de Melo ◽  
Maria do Carmo de Andrade Nono
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Weibull Modulus ◽  
Bending Test ◽  
Sintering Aid ◽  
Zirconia Composites ◽  
Alumina Composites ◽  
Grain Size And Shape ◽  
Zirconia Toughened Alumina ◽  
Zirconia Powders

A comparative study between alumina added niobia ceramics and two alumina zirconia composites from nanostructured TZP (7% and 14% weight) was made. On this composites the zirconia were yttria stabilized and the alumina were submicron structured. As sintering aid a mixture of magnesia, niobia and talc were used on all samples. The sintering was performed at 1450 oC during 60 minutes. The characteristic grain size and shape of an alumina and zirconia powders, aggregates and agglomerates were characterized. The sintering ceramics were evaluated through hardness, fracture toughness and 4 point bending test. Weibull statistic was applied on the flexural results. Although the fracture toughness result from ZTA were lower, and seems to be affected by the liquid fase, the hardness and Weibull modulus were higher than alumina niobia. The grains size and the homogeneity of its distributions on the microstructure of this ceramics was correlated to these higher values. The results from these alumina zirconia composites showed a potential to apply as a ballistic armor material.

Fracture and Mechanical Properties of Fire Resistant Fibre Composites Containing Fine Ground Ceramic Powder

2014 ◽  
Vol 897 ◽  
pp. 192-195 ◽  
Author(s):  
Pavel Reiterman ◽  
Ondřej Holčapek ◽  
Filip Vogel ◽  
Marcel Jogl ◽  
Jaroslava Koťátková
Keyword(s):  
Renewable Resources ◽  
Thermal Load ◽  
High Performance ◽  
Building Materials ◽  
Bending Strength ◽  
Ceramic Powder ◽  
Experimental Program ◽  
Maximum Efficiency ◽  
Fibre Composites ◽  
Aluminous Cement

Significant advances in the field of building materials leads to increasingly frequent enforcement of these high performance materials in real constructions. Efforts to maximize the efficient use of non-renewable resources and especially energy-intensive materials lead to efforts to achieve maximum efficiency and usability [. Paper presents results of an experimental program focused on development of fire-resistance composites based on aluminous cement with fine ground ceramic powder (FGCP). Studied fibre composites were loaded by temperature 600 °C and 1000 °C. The influence of applied thermal load on composites was evaluated by means of fracture energy, compressive strength, bending strength and modulus of elasticity in bending.

Nickel-Alumina Composites: In Situ Synthesis by a Displacement Reaction, and Mechanical Properties

1994 ◽  
Vol 365 ◽  
Author(s):  
Steven A. Jones ◽  
James M. Burlitch ◽  
Ersan Üstündag ◽  
Jeannie Yoo ◽  
Alan T. Zehnder
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Elastic Constants ◽  
High Performance ◽  
In Situ Synthesis ◽  
Displacement Reaction ◽  
Ductile Phase ◽  
Flexure Strength ◽  
Alumina Composites

ABSTRACTNickel-alumina composites have the potential to be high performance materials. Alumina, with its excellent oxidation resistance, combined with a ductile phase such as nickel may provide a tough material with a lower density and higher Young's modulus, overall, a higher specific modulus than typical Superalloys. Dense, interpenetrating Ni-Al2O3 composites were synthesized using a displacement reaction between NiO and aluminum. The resulting composites were characterized in terms of their mechanical properties such as hardness, flexure strength, fracture toughness and elastic constants. The synthesis, characterization, and mechanical properties, as well as the effect of the interpenetrating microstructure on the toughening mechanisms and other properties will be discussed.

The Effect of Dispersion Method on the Mechanical Properties of Graphene Reinforced Alumina Composites

2018 ◽  
Vol 281 ◽  
pp. 93-98 ◽  
Author(s):  
Lu Wang ◽  
Jian Qiang Bi ◽  
Wei Li Wang ◽  
Xu Xia Hao ◽  
Xi Cheng Gao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Great Influence ◽  
Physical And Mechanical Properties ◽  
Structural Ceramics ◽  
Alumina Matrix ◽  
Dispersion Method ◽  
Mechanical Stirring ◽  
Alumina Composites ◽  
Scanning Electron

Due to the remarkable physical and mechanical properties of graphene, it is considered to be one of the most promising reinforcements for structural ceramics. In this paper, the composite material is compacted by hot pressing and the effects of mechanical stirring and ultrasonic on dispersion of graphene in alumina matrix were investigated, which was believed to have a great influence on the mechanical properties of the hot-pressed composites. It is found that from Scanning electron microscopy (SEM) observation. Compared with ultrasonic, the composite, in which graphene was dispersed by mechanical stirring, showed higher bending strength (555.1MPaVS432.3MPa) and fracture toughness (4.4MPa·m1/2VS 4.1MPa·m1/2). The result is much more promising to be employed in the designing and processing of graphene composites.

New Materials for Dental Implantology

2017 ◽  
Vol 750 ◽  
pp. 189-194 ◽  
Author(s):  
Corrado Piconi ◽  
Monica Sandri
Keyword(s):  
Dental Implants ◽  
Lower Risk ◽  
High Performance ◽  
New Technology ◽  
Present Situation ◽  
Metallic Ions ◽  
New Materials ◽  
Metal Free ◽  
High Performance Polymer ◽  
Zirconia Composites

Metal-free implantology with zirconia devices is a relatively new technology. Nevertheless, more and more patients demand this kind of implant in place of the ones made out titanium due to the better aesthetics, lower risk of perimplantitis, concerns about metallic ions release. This paper analyze concisely the present situation of zirconia dental implants, and overviews the developments in progress on devices made out alumina/zirconia composites that will likely replace zirconia in the next future. Besides ceramics, Polyetheretherketone (PEEK) is now proposed for metal-free dentistry, the ceramic-loaded formulation of this high-performance polymer are especially interesting for dental implantology.

scholarly journals Microstructure Evolution and Mechanical Properties of Melt Spun Skutterudite-based Thermoelectric Materials

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 984 ◽  
Author(s):  
Huiyuan Geng ◽  
Jialun Zhang ◽  
Tianhong He ◽  
Lixia Zhang ◽  
Jicai Feng
Keyword(s):  
Mechanical Properties ◽  
Spinodal Decomposition ◽  
Microstructure Evolution ◽  
Thermoelectric Materials ◽  
High Performance ◽  
Melt Spinning ◽  
Bending Strength ◽  
Annealed Sample ◽  
Submicron Scale ◽  
Spinning Process

The rapid solidification of melt spinning has been widely used in the fabrication of high-performance skutterudite thermoelectric materials. However, the microstructure formation mechanism of the spun ribbon and its effects on the mechanical properties are still unclear. Here, we report the microstructure evolution and mechanical properties of La–Fe–Co–Sb skutterudite alloys fabricated by both long-term annealing and melt-spinning, followed by sintering approaches. It was found that the skutterudite phase nucleated directly from the under-cooled melt and grew into submicron dendrites during the melt-spinning process. Upon heating, the spun ribbons started to form nanoscale La-rich and La-poor skutterudite phases through spinodal decomposition at temperatures as low as 473 K. The coexistence of the micron-scale grain size, the submicron-scale dendrite segregation and the nanoscale spinodal decomposition leads to high thermoelectric performance and mechanical strength. The maximum three-point bending strength of the melt spinning sample was about 195 MPa, which was 70% higher than that of the annealed sample.

scholarly journals Mechanical Properties of Hybrid Ultra-High Performance Engineered Cementitous Composites Incorporating Steel and Polyethylene Fibers

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1448 ◽  
Author(s):  
Yingwu Zhou ◽  
Bin Xi ◽  
Kequan Yu ◽  
Lili Sui ◽  
Feng Xing
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
High Performance ◽  
Bending Strength ◽  
Flexural Properties ◽  
Environmental Scanning ◽  
Fiber Volume ◽  
Pseudo Strain Hardening ◽  
Positive Effect ◽  
Opposite Tendency

This paper presents the authors’ newly developed hybrid ultra-high performance (HUHP) engineered cementitious composite (ECC) with steel (ST) and polyethylene (PE) fibers. From this point on it will be referred to as HUHP-ECC. The volumes of steel and PE fibers were adjusted to obtain different mechanical properties, including compressive strength, tensile, and flexural properties. We found that tensile and flexural properties, including bending strength and ductility indexes, increased with higher PE fiber amounts but reduced with the increased ST fiber volume. Notably, the compressive strength had the opposite tendency and decreased with increases in the PE volume. The ST fiber had a significantly positive effect on the compressive strength. The fluidity of HUHP-ECC improved with the increasing amount of ST fiber. The pseudo strain-hardening (PSH) values for all the HUHP-ECC mixtures were used to create an index indicating the ability of strain capacity; thus, the PSH values were calculated to explain the ductility of HUHP-ECC with different fiber volumes. Finally, the morphology of PE and ST fibers at the fracture surface was observed by an environmental scanning electron microscope (ESEM).

Shape recovery characteristics of shape memory cyanate ester/epoxy composite reinforced with calcium sulfate whisker

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yongkun Wang ◽  
Yuting Zhang ◽  
Jinhua Zhang ◽  
Junjue Ye ◽  
Wenchao Tian
Keyword(s):  
Mechanical Properties ◽  
Shape Memory ◽  
Calcium Sulfate ◽  
High Performance ◽  
Shape Recovery ◽  
Bending Strength ◽  
Cyanate Ester ◽  
Content Type ◽  
Shape Memory Composites ◽  
Calcium Sulfate Whiskers

Purpose The purpose of this paper is to study the influence of calcium sulfate whiskers (CSWs) on the thermodynamic properties and shape memory properties of epoxy/cyanate ester shape memory composites. Design/methodology/approach To improve the mechanical properties of shape memory cyanate ester (CE)/epoxy polymer (EP) resin, high performance CSWs were used to reinforce the thermo-induced shape memory CE/EP composites and the shape memory CSW/CE/EP composites were prepared by molding. The effect of CSW on the mechanical properties and shape memory behavior of shape memory CE/EP composites was investigated. Findings After CSW filled the shape memory CE/EP composites, the bending strength of the composites is greatly improved. When the content of CSW is 5 Wt.%, the bending strength of the composite is 107 MPa and the bending strength is increased by 29 per cent compared with bulk CE/EP resin. The glass transition temperature and storage modulus of the composites were improved in CE/EP resin curing system. However, when the content of CSW is more than 10 Wt.%, clusters are easily formed between whiskers and the voids between whiskers and matrix increase, which will lead to the decrease of mechanical properties of composites. The results of shape memory test show that the shape memory recovery time of the composites decreases with the decrease of CSW content at the same temperature. In addition, the shape recovery ratio of the composites decreased slightly with the increase of the number of thermo-induced shape memory cycles. Research limitations/implications A simple way for fabricating thermo-activated SMP composites has been developed by using CSW. Originality/value The outcome of this study will help to fabricate the SMP composites with high mechanical properties and the shape memory CSW/CE/EP composites are expected to be used in space deployable structures.

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