Enhanced Mechanical Properties in ED-Machinable Zirconia-Tungsten Carbide Composites with Yttria-Neodymia Co-Stabilized Zirconia Matrix

Gommeringer, Andrea; Kern, Frank; Gadow, Rainer

doi:10.3390/ceramics1010004

Cited by 10 publications

(6 citation statements)

References 35 publications

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“…It can be seen that grinding induced some tetragonal to monoclinic phase transformation. However, the tetragonal peak (111) does not show any anomaly or shoulder corresponding to a cubic phase; in contrast to what has been reported recently for zirconia composites doped with Nd 2 O 3 and Y 2 O 3 [33]. Figure 5 a, b shows the XRD patterns made on the cut surfaces of 5CeGd and 10CeGd sintered at 1400 °C.…”

Section: Mechanical Propertiesmentioning

confidence: 71%

Effect of gadolinia addition on the mechanical and physical properties of zirconia/ceria ceramics

et al. 2020

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In this work, zirconia powders containing 5 and 10 mol % ceria were prepared by co-precipitation method followed by doping with small amounts (< 1 mol %) of gadolinia which stabilized the tetragonal phase. X-ray diffraction and scanning electron microscopy were used for phase analysis and microstructure examination, respectively. The sintered compacts showed fine grained, dense, tough and strong ceramics. Strength up to 795.8 MPa and toughness of 17 MPa√m have been obtained. These ceramics showed higher toughness than yttria-doped tetragonal zirconia polycrystals (Y-TZP) and a higher strength than the ceria tetragonal zirconia polycrystals (Ce-TZP). The high fracture toughness was attributed to the tetragonal-to-monoclinic phase transformation which was associated with ferroelastic domain switching. The domain switching toughening has been discussed in view of Chevalier's model. Four-point bending strengths for the samples tested in the as cut state are higher than those tested in the as-sintered or the ground states.

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Section: Mechanical Propertiesmentioning

confidence: 71%

Effect of gadolinia addition on the mechanical and physical properties of zirconia/ceria ceramics

et al. 2020

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“…For example, in the case of processing naturally widely available oxide ceramics such as ZrO 2 and Al 2 O 3 , their melting points are of 2715 • C and 2054 • C, respectively [33,49,50,68]. The introduction of an additional process initiator can result in the physical ablation of the ceramics with the formation of the conductive form ZrC and unstable compound Al 4 C 3 , which can theoretically assist processing.…”

Section: Discussionmentioning

confidence: 99%

“…The analysis of the leading world scientific competitors in this domain shows that the world community is separated as it was mentioned above. One group of scientists is focused on the modification of nanoceramics with conductive inclusions to create systems such as ZrO 2 -Ta, ZrO 2 -TiC, ZrO 2 -TiCN, Si 3 N 4 -TiC, Si 3 N 4 -TiCN, Al 2 O 3 -TiC, Al 2 O 3 -TiCN [49][50][51][52][53][54][55][56][57][58][59], as well as inclusions based on graphene and oxide graphene and graphene nanotubes [23,[60][61][62][63][64]. Another group of scientists has focused their research on the processing capabilities of existed ceramics and non-conductive ceramic composites.…”

Section: The Main Scientific Competitorsmentioning

confidence: 99%

On Electrical Discharge Machining of Non-Conductive Ceramics: A Review

et al. 2019

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The inability of ceramic and nanoceramic processing without expensive diamond tools and with a high-material-removal rate hampers the scope of its potential applications and does not allow humanity to make a full shift to the sixth technological paradigm associated with Kuhn scientific revolutions and Kondratieff's waves and restrains the growth of the economy. The authors completed a review on the research state of ceramic and nanoceramic processing by electrical discharge machining, which is possibly solved by two principal approaches associated with the usage of standard commercially available machine tools. The first approach is related to the introduction of expensive secondary phase; the second approach proposes initiate processing by adding auxiliary electrodes in the form of coating, suspension, aerosol, or 3D-printed layer based on the components of silver, copper, or graphite in combination with an improved dielectric oil environment by introducing graphite or carbon nanoparticles, which is hugely relevant today.Technologies 2019, 7, 55 2 of 16 of cutting tools limits the resulting geometry of the product. Other machining methods such as vibroacoustic machining, laser and electron beam scribing, selective laser sintering with a binder, find their specific place in the processing of ceramics. However, they do not allow the receiving of all geometrically possible shapes of the product without losses on the operational parameters of ceramics [16][17][18].One of the most popular methods for the production of parts, regardless of their hardness, is electrical discharge machining (EDM). However, it requires the material to be conductive [19][20][21]. The process of electrical erosion of the material consists of initiating electric pulses in the interelectrode gap, in the breakdown of the dielectric medium in the gap, in establishing a discharge channel, where the temperature reaches more than 10,000 • C (low-temperature plasma). Due to such temperatures, the material is ablated, the drops of cooled material as eroded debris are washed away by the flow of the dielectric medium, and the electrodes again approach to resume the cycle. Thus, a unique crater-like topology on the surface of the workpiece is created [22][23][24][25].The inability of ceramics and nanoceramics to conduct current hampers the scope of its potential applications and restrains the growth of the progress and the switch to the next technological paradigm that most of the scientists associate with the term "nano" [26][27][28][29][30][31][32].Thus, it can be concluded that the study and development of a method for electrical discharge machining of non-conductive ceramics and nanoceramics are incredibly relevant today.The authors propose to apply the dialectical approach of cognition as a scientific approach to solve the formulated scientific problem. The dialectical approach includes the systematization and updating of existing knowledge and new data about the object of research.

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“…To achieve this goal, it is necessary to perform a careful control of each manufacturing step, from the synthesis of the composite powders to the forming of the green parts and their densification. This Special Issue "Advances in the Field of Nanostructured Ceramic Composites" provides examples of the outstanding properties which could be achieved today by the development of suitable nanocomposite ceramics, both in the field of structural [11][12][13] and functional materials [14]. In spite of the differences in composition and manufacturing methods between the materials here illustrated, as a common point, the manuscripts belonging to this Special Issue clearly evidence the need of optimizing many parameters of design (e.g., material composition [12,13], second-phase content, etc.)…”

mentioning

confidence: 99%

“…and processing (e.g, dispersion, homogenization [11], sintering, etc. [12]) to achieve the expected performance. Most of all, the attainment of a homogeneous distribution of nanosized particles inside the matrix materials is a still a challenging issue, in particular, when a fine control of the location of the particles in the matrix material is required.…”

mentioning

confidence: 99%