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Author

Jerzy Lis

Bio: Jerzy Lis is an academic researcher from AGH University of Science and Technology. The author has contributed to research in topics: Sintering & Hot pressing. The author has an hindex of 17, co-authored 84 publications receiving 1285 citations.
Topics: Sintering, Hot pressing, Ceramic, Combustion, Spinel


Papers
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Journal ArticleDOI
TL;DR: Using powders of Ti and Si and carbon black as reactants, a material composed mainly of the ternary compound Ti 3 SiC 2 and of minor amounts of TiC was synthesized by the method of solid combustion as mentioned in this paper.
Abstract: Using powders of Ti and Si and carbon black as reactants, a material composed mainly of the ternary compound Ti 3 SiC 2 and of minor amounts of TiC was synthesized by the method of solid combustion. Following ignition at 1050°C, complete conversion of the reactants to the products was observed in a time of 2 to 5 s. The product obtained from the molar composition 3Ti:Si:2C has properties similar to the CVD-derived polycrystalline Ti 3 SiC 2 , which is a ‘soft’ ceramic material capable of being shaped by metalworking methods and shows a high resistance to oxidation and to aggressive environments.

222 citations

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TL;DR: Different ternary carbide phases were successfully synthesized in a self-sustaining regime as mentioned in this paper, and reaction conditions and X-ray diffraction patterns of different ternaries were presented.
Abstract: Different ternary carbide phases, namely Ti3AlC2, Ti3AlC, and Ti2AlC, were successfully synthesized in a self-sustaining regime. Direct reactions among elemental powders of titanium, aluminum, and carbon are strongly exothermic, and the resulting reaction products consist of binary carbides and they are partially molten. The use of TiAl, instead of elemental titanium and aluminum, significantly reduces the combustion temperature. As a result, ternary titanium aluminum carbide phases are formed. In addition, the combustion-synthesized products are not sintered and easy to deagglomerate. Reaction conditions and X-ray diffraction patterns of different ternary phases formed in a self-sustaining regime are presented.

107 citations

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TL;DR: In this paper, the physicochemical properties of the synthesized apatites were analyzed using various analytical methods, such as X-ray diffraction (XRD), infrared spectroscopy (FTIR), and high-resolution solid-state nuclear magnetic resonance (SSNMR).

98 citations

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TL;DR: In this article, the crystal structure of melted CaZrO 3 was compared with a conventionally synthesized material and it was found that the obtained material has an orthorhombic perovskite-like structure.
Abstract: Calcium zirconate (CaZrO 3 ), because of its high melting point, low thermal expansion coefficient, high strength and excellent corrosion resistance against alkali oxides, is a good candidate for a novel refractory material. CaZrO 3 is mostly synthesized by the reaction in the solid state but the material obtained in such a way often suffers low bulk density, high porosity and other defects which lower its potential application value. To overcome these obstacles a novel synthesis method by an electric arc melting technique was proposed. The crystal structure of melted CaZrO 3 was compared with a conventionally synthesized material. According to X-ray measurements the obtained material has an orthorhombic perovskite-like structure. Its stoichiometry was confirmed by the scanning electron microscope and EDS analysis. The material is almost poreless with its density close to theoretical. The estimated crystal structure parameters were used to calculate the electronic structure of CaZrO 3 using the full potential linear augmented plane wave (FLAPW) method. It has been found that CaZrO 3 is an insulator with the energy band gap of 4.1 eV. The Ca–O bond is typically ionic while Zr–O bond is of a significant covalent character.

84 citations

Journal ArticleDOI
TL;DR: In this article, the authors present the development of >40vol.%, UV curable transparent silica nanodispersions having viscosities suitable for stereolithography applications, and the transformation of selected dispersions to self-supporting silica glass sheets through UV curing, debinding and sintering was investigated by TGA/DTA, dilatometry and XRD.
Abstract: Silica microcomponents are attractive for applications requiring high temperature stability and chemical durability such as in microreactors. Rapid prototyping methods of forming ceramic dispersions hold great potential for manufacturing of microreactors. Stereolithography for example can benefit from highly solid loaded, low viscosity and high transparency dispersions. This article presents the development of >40 vol.%, UV curable transparent silica nanodispersions having viscosities suitable for stereolithography applications. The main parameters enabling these high loading dispersions are minimization of the Van der Waals attractive forces and affinity of monomer end group for the silica surface (e.g. hydrogen bonding). The minimization of the Van der Waals attraction is achieved by refractive index matching of the nanosilica and UV curable acrylate monomers. This results also in highly transparent dispersions having curing depths in the order of 10 mm in the UVA range. The transformation of selected dispersions to self-supporting silica glass sheets through UV curing, debinding and sintering was investigated by TGA/DTA, dilatometry and XRD.

67 citations


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Journal ArticleDOI
TL;DR: In this paper, a polycrystalline bulk sample of Ti sub 3, SiC sub 2 was fabricated by reactively hot-pressing Ti, graphite, and SiC powders at 40 MPa and 1,600 C for 4 h.
Abstract: Polycrystalline bulk samples of Ti{sub 3}SiC{sub 2} were fabricated by reactively hot-pressing Ti, graphite, and SiC powders at 40 MPa and 1,600 C for 4 h. This compound has remarkable properties. Its compressive strength, measured at room temperature, was 600 MPa, and dropped to 260 MPa at 1,300 C in air. Although the room-temperature failure was brittle, the high-temperature load-displacement curve shows significant plastic behavior. The oxidation is parabolic and at 1,000 and 1,400 C the parabolic rate constants were, respectively, 2 {times} 10{sup {minus}8} and 2 {times} 10{sup {minus}5} kg{sup 2}{center_dot}m{sup {minus}4}{center_dot}s{sup {minus}1}. The activation energy for oxidation is thus {approx}300 kJ/mol. The room-temperature electrical conductivity is 4.5 {times} 10{sup 6} {Omega}{sup {minus}1}{center_dot}m{sup {minus}1}, roughly twice that of pure Ti. The thermal expansion coefficient in the temperature range 25 to 1,000 C, the room-temperature thermal conductivity, and the heat capacity are respectively, 10 {times} 10{sup {minus}6} C{sup {minus}1}, 43 W/(m{center_dot}K), and 588 J/(kg{center_dot}K). With a hardness of 4 GPa and a Young`s modulus of 320 GPa, it is relatively soft, but reasonably stiff. Furthermore, Ti{sub 3}SiC{sub 2} does not appear to be susceptible to thermal shock; quenching from 1,400 C into water does not affect the postquench bend strength.more » As significantly, this compound is as readily machinable as graphite. Scanning electron microscopy of polished and fractured surfaces leaves little doubt as to its layered nature.« less

1,491 citations

Journal ArticleDOI
TL;DR: A review on the latest advances in the 3D printing of ceramics and present the historical origins and evolution of each related technique is presented in this paper. And the main technical aspects, including feedstock properties, process control, post-treatments and energy source-material interactions, are also discussed.
Abstract: Along with extensive research on the three-dimensional (3D) printing of polymers and metals, 3D printing of ceramics is now the latest trend to come under the spotlight. The ability to fabricate ceramic components of arbitrarily complex shapes has been extremely challenging without 3D printing. This review focuses on the latest advances in the 3D printing of ceramics and presents the historical origins and evolution of each related technique. The main technical aspects, including feedstock properties, process control, post-treatments and energy source–material interactions, are also discussed. The technical challenges and advice about how to address these are presented. Comparisons are made between the techniques to facilitate the selection of the best ones in practical use. In addition, representative applications of the 3D printing of various types of ceramics are surveyed. Future directions are pointed out on the advancement on materials and forming mechanism for the fabrication of high-performance ceramic components.

1,082 citations

01 Jan 2007
TL;DR: Two algorithms for generating the Gaussian quadrature rule defined by the weight function when: a) the three term recurrence relation is known for the orthogonal polynomials generated by $\omega$(t), and b) the moments of the weightfunction are known or can be calculated.
Abstract: Most numerical integration techniques consist of approximating the integrand by a polynomial in a region or regions and then integrating the polynomial exactly. Often a complicated integrand can be factored into a non-negative ''weight'' function and another function better approximated by a polynomial, thus $\int_{a}^{b} g(t)dt = \int_{a}^{b} \omega (t)f(t)dt \approx \sum_{i=1}^{N} w_i f(t_i)$. Hopefully, the quadrature rule ${\{w_j, t_j\}}_{j=1}^{N}$ corresponding to the weight function $\omega$(t) is available in tabulated form, but more likely it is not. We present here two algorithms for generating the Gaussian quadrature rule defined by the weight function when: a) the three term recurrence relation is known for the orthogonal polynomials generated by $\omega$(t), and b) the moments of the weight function are known or can be calculated.

1,007 citations

Journal ArticleDOI
TL;DR: A review of the self-propagating high-temperature synthesis (SHS) method is presented in this article, which emphasizes the mechanisms of the rapid, non-isothermal reactions associated with this method.

1,002 citations