High Temperature Compounds

Nowotny, H.; Windisch, Stefan

doi:10.1146/annurev.ms.03.080173.001131

Cited by 19 publications

(10 citation statements)

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“…T ransition metal carbides, such as TiC, ZrC, HfC, and NbC, display a number of excellent properties, such as high melting point, high hardness, good wear resistance, good thermal shock resistance, and high thermal and electrical conductivity, which make them promising high‐temperature structural materials and wear‐resistant coating materials 1,2 . However, the poor oxidation resistance and intrinsic brittleness constrain their further applications.…”

Section: Introductionmentioning

confidence: 99%

Tribological Properties of a Zr₂Al₃C₄Ceramic at Ambient Temperature

Bao

et al. 2009

Journal of the American Ceramic Society

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In this work, reciprocating ball-on-flat sliding friction and wear tests as well as two-body abrasive wear tests were performed on Zr 2 Al 3 C 4 , a new type of ceramic material. In the sliding wear tests, a Si 3 N 4 ball and an AISI 52100 steel ball were used as counter materials. When Zr 2 Al 3 C 4 was slid against an AISI 52100 ball, the coefficient of friction (COF) was as low as 0.20-0.42, being independent of normal loads, and the wear rates of Zr 2 Al 3 C 4 and AISI 52100 steel were in the range of 10 À4-10 À5 mm 3 /m. A tribofilm between the tribopair was presumed to be responsible for the low COF and wear rate. According to Raman and energy-dispersive spectroscopy analysis, the tribofilm consists of a mixture of oxides of Zr, Al, and Fe as well as amorphous carbon. When Zr 2 Al 3 C 4 was slid against a Si 3 N 4 ball, a transition from mild wear to severe wear was observed as the normal load increased. The transition occurs under certain contact stresses after a damage-accumulating period. In the two-body abrasive wear test, surface chipping and fragmentation resulting from coalescence of surface and subsurface microcracks were the main material removal mechanisms of Zr 2 Al 3 C 4 .

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Section: Introductionmentioning

confidence: 99%

Tribological Properties of a Zr₂Al₃C₄Ceramic at Ambient Temperature

Bao

et al. 2009

Journal of the American Ceramic Society

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“…1 However, the poor oxidation resistance and intrinsic brittleness hinder their extensive applications in hightemperature environments. 1 However, the poor oxidation resistance and intrinsic brittleness hinder their extensive applications in hightemperature environments.…”

Section: Introductionmentioning

confidence: 99%

Layered stacking characteristics of ternary zirconium aluminum carbides

Lin

et al. 2007

J. Mater. Res.

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Layered stacking characteristics of ternary Zr-Al-C carbides were investigated using scanning transmission electron microscopy (STEM). Three previously unknown compounds, i.e., Zr 4 Al 3 C 6 , Zr 5 Al 6 C 9 , and Zr 7 Al 6 C 11 were identified. The present study extends the structural information of ternary Zr-Al-C ceramics. The influence of the thickness of the NaCl-type Zr-C slab on the elastic properties of ternary Zr-Al-C ceramics is discussed based on first-principles calculations. In addition, direct atomic-resolution observations illustrate the process for forming the unique layered crystal structures of ternary Zr-Al-C ceramics. These results also provide insights into the formation mechanism of layered ternary Zr-Al-C carbides.

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“…Attempts to synthesize them in bulk always resulted in samples containing, in most cases, TiC, and sometimes SiC, as ancillary, unwanted phases (Lis et al, 1993;Morgiel, Lis, and Pampuch, 1996;Pampuch and Lis, 1995;Pampuch et al, 1989). For example, despite a sentence buried in one of Nowotny's papers claiming Ti 3 SiC 2 does not melt but dissociates at 1700 • C into TiC and a liquid (Nowotny and Windisch, 1973), the erroneous information that it has a melting point of over 3000 • C is still being disseminated by some. For example, despite a sentence buried in one of Nowotny's papers claiming Ti 3 SiC 2 does not melt but dissociates at 1700 • C into TiC and a liquid (Nowotny and Windisch, 1973), the erroneous information that it has a melting point of over 3000 • C is still being disseminated by some.…”

Section: History Before 1995mentioning

confidence: 99%

Introduction

2013

MAX Phases

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The M n+1 AX n , or MAX, phases are layered, hexagonal, early transition-metal carbides and nitrides, where n = 1, 2, or 3 ''M'' is an early transition metal, ''A'' is an A-group (mostly groups 13 and 14) element, and ''X'' is C and/or N. In every case, near-close-packed M layers are interleaved with layers of pure group-A element with the X atoms filling the octahedral sites between the former (Figure 1.1a-c). The M 6 X octahedra are edge-sharing and are identical to those found in the rock salt structure. The A-group elements are located at the center of trigonal prisms that are larger than the octahedral sites and thus better able to accommodate the larger A atoms. The main difference between the structures with various n values ( Figure 1.1a-c) is in the number of M layers separating the A layers: in the M 2 AX, or 211, phases, there are two; in the M 3 AX 2 , or 312, phases there are three; and in the M 4 AX 3 , or 413, phases, there are four. As discussed in more detail in later chapters, this layering is crucial and fundamental to understanding MAX-phase properties in general, and their mechanical properties in particular. Currently, the MAX phases number over 60 (Figure 1.2) with new ones, especially 413s and solid solutions, still being discovered.Most of the MAX phases are 211 phases, some are 312s, and the rest are 413s. The M group elements include Ti, V, Cr, Zr, Nb, Mo, Hf, and Ta. The A elements include Al, Si, P, S, Ga, Ge, As, Cd, In, Sn, Tl, and Pb. The X elements are either C and/or N.Thermally, elastically, and electrically, the MAX phases share many of the advantageous attributes of their respective binary metal carbides or nitrides: they are elastically stiff, and electrically and thermally conductive. Mechanically, however, they cannot be more different: they are readily machinable -remarkably a simple hack-saw will do (Figure 1.3) -relatively soft, resistant to thermal shock, and unusually damage-tolerant. They are the only polycrystalline solids that deform by a combination of kink and shear band formation, together with the delaminations of individual grains. Dislocations multiply and are mobile at room temperature, glide exclusively on the basal planes, and are overwhelmingly arranged either MAX Phases: Properties of Machinable Ternary Carbides and Nitrides, First Edition. Michel W. Barsoum.

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High Temperature Compounds

Cited by 19 publications

References 3 publications

Tribological Properties of a Zr₂Al₃C₄Ceramic at Ambient Temperature

Tribological Properties of a Zr₂Al₃C₄Ceramic at Ambient Temperature

Layered stacking characteristics of ternary zirconium aluminum carbides

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High Temperature Compounds

Cited by 19 publications

References 3 publications

Tribological Properties of a Zr2Al3C4Ceramic at Ambient Temperature

Tribological Properties of a Zr2Al3C4Ceramic at Ambient Temperature

Layered stacking characteristics of ternary zirconium aluminum carbides

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Tribological Properties of a Zr₂Al₃C₄Ceramic at Ambient Temperature

Tribological Properties of a Zr₂Al₃C₄Ceramic at Ambient Temperature