Effect of CrB2 addition on densification, properties and oxidation resistance of TiB2

Murthy, T.S.R.Ch.; Sonber, J.K.; Subramanian, C.; Fotedar, R.K.; Gonal, M. R.; Suri, A.K.

doi:10.1016/j.ijrmhm.2009.06.004

Cited by 49 publications

(18 citation statements)

References 43 publications

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“…The vitreous zones looked like those evidenced by Murthy et al [19] when oxidizing the composite TiB 2 + 10%CrB 2 at 1000 °C. According to Murthy et al [19] , such vitreous zones result from the coagulation of droplets of liquid oxide, either CrBO 3 or B 2 O 3 in Murthy's study. This way, it seemed that during the oxidation process a liquid boron rich oxide formed at the top of the oxide film within the spots.…”

Section: Products Of Oxidation Inside the Spotssupporting

confidence: 73%

“…Furthermore, when oxidizing the CrB 2 phase it was pointed out that B 2 O 3 can react with Cr 2 O 3 to form CrBO 3 . Murthy et al [19] re ported the oxide CrBO 3 in the 800 °C 1000 °C range, while Emiliani et al [21] reported the oxide CrBO 3 at 1100 °C. The CrBO 3 oxide is liquid above 855 °C and also decomposes in the volatile oxides Cr 2 O 3 and B 2 O 3 above 1200 °C [19] .…”

Section: Introductionmentioning

confidence: 99%

“…Murthy et al [19] re ported the oxide CrBO 3 in the 800 °C 1000 °C range, while Emiliani et al [21] reported the oxide CrBO 3 at 1100 °C. The CrBO 3 oxide is liquid above 855 °C and also decomposes in the volatile oxides Cr 2 O 3 and B 2 O 3 above 1200 °C [19] . The oxides which liquefy at high tem perature can hardly be evidenced on XRD patterns [19] but they have a characteristic appearance: they appear as vitreous phases once solidified [18 , 19 , 21] .…”

Section: Introductionmentioning

confidence: 99%

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Flash oxidation tests to evidence the segregation of boron at the grain boundaries of superalloy Inconel 718

2021

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In this study very short oxidation tests, called flash oxidation tests, were carried out at high temperature on samples of superalloy Inconel 718 containing some boron. Following these tests, a specific oxidation pattern was evidenced: spots were observed on the oxide film, these spots being discontinuously distributed along the grain boundaries. Whether outside or inside the spots, the oxide film exhibited the same three oxide layers which were likely rutile oxide (Cr,Nb,Ti)0 2 , chromia oxide Cr 2 O 3 and spinel oxide (Ni,Fe)(Cr,Fe) i O 4 • However, inside the spots the oxide film was characterized by thicker oxide layers, a slightly different chemical composition of the spinel layer, and vitreous oxides at the top. Moreover, all the intergranular (Nb,Mo) i CrB 2 borides of the mi crostructure were involved in this specific oxidation pattern, thus leading to the suspicion of high boron concen trations within the spots. FEG-EPMA analyses confumed that, during the oxidation process, boron a toms diffused fr001 the matrix to the oxide film, especially within the spots. Actually, the spots revealed areas where boron was highly concentrated just before oxidation. Such areas originated from the non-equilibrium segregation of boron near grain boundaries, which is a classical phenomenon when cooling and/or reheating a boron

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Section: Products Of Oxidation Inside the Spotssupporting

confidence: 73%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Flash oxidation tests to evidence the segregation of boron at the grain boundaries of superalloy Inconel 718

2021

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“…UHTC composites-for example TiB 2 -TiC, ZrB 2 -SiC, ZrB 2 -TaB 2 , and NbB 2 -SiC-have been of great importance for extreme environment applications requiring high thermal-shock resistance and durability against a rapid temperature change [4][5][6][7]. In addition, borides of chromium and tungsten have been recognized as effective reinforcements for UHTCs to improve densification, mechanical properties, and oxidation resistance [8,9].…”

Section: Introductionmentioning

confidence: 99%

“…Hot pressing (HP) and spark plasma sintering (SPS) are two most commonly-used fabrication routes to prepare UHTCs and composites on their basis [2][3][4][5][6][7][8]. Combustion synthesis in the mode of self-propagating high-temperature synthesis (SHS) has been a promising alternative, which takes advantage of highly exothermic reactions, and hence, has merits of low energy requirement, short processing time, simplicity, and high-purity products [10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Combustion Synthesis of UHTC Composites from Ti–B4C Solid State Reaction with Addition of VIb Transition Metals

Yeh

Lin

2017

Coatings

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UHTC composites were prepared by self-propagating high-temperature synthesis (SHS) from the Ti-B 4 C reaction system with addition of Cr, Mo, and W. The starting sample composition was formulated as (3−x)Ti + B 4 C + xMe with x = 0.1-1.0 and Me = Cr, Mo, or W. For all samples conducted in this study, self-sustaining combustion was well established and propagated with a distinct reaction front. With no addition of Cr, Mo, or W, solid state combustion of the 3Ti + B 4 C sample featuring a combustion front temperature (T c ) of 1766 • C and a combustion wave velocity (V f ) of 16.5 mm/s was highly exothermic and produced an in situ composite of 2TiB 2 + TiC. When Cr, Mo, or W was adopted to replace a portion of Ti, the reaction exothermicity was lowered, and hence, a significant decrease in T c (from 1720 to 1390 • C) and V f (from 16.1 to 3.9 mm/s) was observed. With addition of Cr, Mo, and W, the final products were CrB-, MoB-, and WB-added TiB 2 -TiC composites. The absence of CrB 2 , MoB 2 , and WB 2 was attributed partly to the loss of boron from thermal decomposition of B 4 C and partly to lack of sufficient reaction time inherent to the SHS process.

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Ceramic Matrix Composites in Ti‐B‐Cr and Ti‐B‐Nb Systems Fabricated “In Situ” by Self‐Propagating High‐Temperature Synthesis

Ziemnicka-Sylwester

2014

Ceramic Materials for Energy Applications IV

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Effect of CrB2 addition on densification, properties and oxidation resistance of TiB2

Cited by 49 publications

References 43 publications

Flash oxidation tests to evidence the segregation of boron at the grain boundaries of superalloy Inconel 718

Flash oxidation tests to evidence the segregation of boron at the grain boundaries of superalloy Inconel 718

Combustion Synthesis of UHTC Composites from Ti–B4C Solid State Reaction with Addition of VIb Transition Metals

Ceramic Matrix Composites in Ti‐B‐Cr and Ti‐B‐Nb Systems Fabricated “In Situ” by Self‐Propagating High‐Temperature Synthesis

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