Effects of additions of ZrC and ZrB2 on oxidation resistance of C/SiC/B4C composites

Ogawa, Ichitaro; Yamamoto, Tatsuya

doi:10.1007/bf00729419

Cited by 10 publications

(8 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Highdensity materials were obtained through liquid phase sintering at processing temperatures well below those needed for undoped ZrB 2 , and enhanced properties such as hardness, fracture toughness, and strength were also successfully achieved. [3][4][5][8][9][10][11][12] Complexshaped components of these materials are usually manufactured by electrical discharge machining. 1 In fact, the mechanical and physical properties of monolithic zirconium diboride are sometimes inappropriate for specific applications.…”

mentioning

confidence: 99%

Oxidation of ZrB[sub 2]-Based Ceramics in Dry Air

Monteverde¹,

Bellosi²

2003

J. Electrochem. Soc.

277

212

View full text Add to dashboard Cite

The oxidation behavior of three different ZrB2 -based ceramics, a monolithic ZrB2 and two ZrB2normalSiC composites, was studied up to 1350°C and under isothermal conditions at 1120°C for 20 h. Oxidation kinetics and microstructural changes in the oxidized specimens indicate that the monolithic ZrB2 has low thermal stability. On the contrary, the introduction of SiC particles markedly improves oxidation resistance due to the formation of an adherent and protective borosilicate glass layer that coats the sample surface, effectively limiting the inward diffusion of oxygen toward the reaction interface. The influence of the secondary grain boundary phases on oxidation is discussed. © 2003 The Electrochemical Society. All rights reserved.

show abstract

mentioning

confidence: 99%

Oxidation of ZrB[sub 2]-Based Ceramics in Dry Air

Monteverde¹,

Bellosi²

2003

J. Electrochem. Soc.

277

212

View full text Add to dashboard Cite

show abstract

“…TambiŽn pueden formarse vidrios de silicoborato a partir de mezclas de otros compuestos, como TiB 2 , MoSi 2 , ZrB 2 , TiSi 2 , HfB 2 , etc. (41)(42)(43)(44).…”

Section: 21-capa Internaunclassified

Materiales compuestos C/SiC para aplicaciones estructurales de alta temperatura. Parte II: Sistemas de protección contra la oxidación

Aparicio¹,

Durán²

2001

Bol. Soc. Esp. Ceram. Vidr.

View full text Add to dashboard Cite

La utilizaci-n de los materiales compuestos C/SiC en aplicaciones estructurales a alta temperatura est ‡ limitada por la elevada velocidad de oxidaci-n de la fibra de carbono a temperaturas superiores de 450¼C. En esta segunda parte del trabajo se realiza una revisi-n de las posibilidades de protecci-n contra la oxidaci-n de estos materiales, incluyendo inhibidores, modificaci-n superficial del material compuesto, recubrimientos e infiltraci-n previa del sustrato. La eficacia de los inhibidores de la reacci-n de oxidaci-n est ‡ restringida a temperaturas de hasta 850¼C, mientras que la modificaci-n superficial del material compuesto da lugar a capas delgadas y poco resistentes a los ciclos tŽrmicos. En cambio, los recubrimientos son el mŽto-do m ‡s empleado porque permiten combinar composiciones y espesores de capa muy variados. La estructura multicapa es especialmente interesante en el caso de aplicaciones con intervalos de temperatura de trabajo amplios y cuando el material va a estar sometido a choques tŽrmicos. La infiltraci-n de la porosidad del sustrato s-lo mejora ligeramente la resistencia a la oxidaci-n del material compuesto C/SiC al reducir los caminos de acceso del ox'geno a las fibras de carbono. Sin embargo, la infiltraci-n complementa en gran medida las propiedades antioxidantes de los recubrimientos en el intervalo de bajas temperaturas, ya que Žstos suelen presentar fisuras abiertas por diferencias de dilataci-n tŽrmica con el sustrato. Palabras clave: C/SiC, materiales compuestos, protecci-n antioxidante C/SiC composites for high temperature structural applications. Part II: Oxidation protection systemsThe fact which currently excludes the use of C/SiC composites in high temperature structural applications is the high oxidation rate of carbon fibres at temperatures higher than 450¼C. In this second part of the paper, a review of the different oxidation protection systems, including inhibitors, surface modification of composites, coatings and previous infiltration of the substrates, has been carried out. The addition of inhibitors reduces the oxidation rate, but only up to 850¼C, while the surface modification of composites leads to thin coatings with poor thermal shock resistance. On the other hand, the external layers are the most usual method employed because allows combining different compositions and thicknesses. The multilayer coatings are especially interesting in applications with wide temperature range and thermal shocks requirements. The infiltration of substrate porosity improves slightly the oxidation resistance of C/SiC composites reducing the oxygen accessibility to carbon fibres. However, the infiltration complements very well the oxidation protection performance of a coating system at low temperature, since these normally present open cracks due to mismatch between coating and substrate thermal expansion coefficients. Keywords: C/SiC, composites, oxidation protection 1.-INTRODUCCIîNLas importantes propiedades de los materiales compuestos C/SiC, propiedades mec ‡nicas a alta tempe...

show abstract

“…Carbon materials, however, are claimed to have certain disadvantages such as low mechanical strength and low degree of oxidation resistance at high temperature. The fabrication of carbon-ceramic composites seems to be an adequate way to obtain materials with better mechanical properties and oxidation resistance [1][2][3][4], but usually their mass production is expensive [1]. One of the main problems of the process is the low sinterability of the carbon source with most refractory powders [2].…”

Section: Introductionmentioning

confidence: 99%

“…The fabrication of carbon-ceramic composites seems to be an adequate way to obtain materials with better mechanical properties and oxidation resistance [1][2][3][4], but usually their mass production is expensive [1]. One of the main problems of the process is the low sinterability of the carbon source with most refractory powders [2]. Some papers have reported the fabrication of carbon-ceramic composites using self-sintering ground raw coke, with improved mechanical properties and oxidation resistance, with the advantage of not requiring the use of a binder or hot-pressing processes [1][2][3][4].…”

Section: Introductionmentioning

confidence: 99%

“…One of the main problems of the process is the low sinterability of the carbon source with most refractory powders [2]. Some papers have reported the fabrication of carbon-ceramic composites using self-sintering ground raw coke, with improved mechanical properties and oxidation resistance, with the advantage of not requiring the use of a binder or hot-pressing processes [1][2][3][4]. However, these processes usually require the mixture of the coke particles and the ceramic precursor, which may lead to the presence of inhomogeneities in the material or unwanted accumulations of the ceramic component.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation