Thermal Shock Resistance of Nextel™610 and Nextel™720 Continuous Fiber-Reinforced Mullite Matrix Composites

Simon, Reinhard A.; Supancic, Peter

doi:10.1002/9780470291191.ch17

Cited by 5 publications

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“…It has been shown that porous‐matrix CFCCs are relatively notch insensitive 5,6 . Furthermore, they exhibit reasonable fatigue performance and useful thermal shock resistance 7,8 . However, the long‐term performance of all‐oxide, porous‐matrix CFCCs at the targeted service temperature (above 1200°C) is dictated by the stability of the microstructures of both the fibers and the matrix.…”

Section: Introductionmentioning

confidence: 99%

“…5,6 Furthermore, they exhibit reasonable fatigue performance and useful thermal shock resistance. 7,8 However, the long-term performance of all-oxide, porous-matrix CFCCs at the targeted service temperature (above 12001C) is dictated by the stability of the microstructures of both the fibers and the matrix. Shortcomings in high-temperature long-term applications are strength degradation and a loss in damage tolerance due to matrix sintering and grain growth in the fibers.…”

Section: Introductionmentioning

confidence: 99%

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Progress in Processing and Performance of Porous‐Matrix Oxide/Oxide Composites

Simon

2005

Int J Applied Ceramic Tech

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All‐oxide continuous fiber‐reinforced ceramic matrix composites are enabling materials for high‐temperature structural applications in oxidizing environments. However, their industrial use requires further improvements in material performance as well as a significant reduction of the processing costs. This article gives some insight into a novel colloidal processing route. A porous mullite matrix was designed to obtain damage‐tolerant behavior as well as high‐temperature long‐term stability. Laminated composites were formed with conventional techniques similar to the manufacture of polymer matrix composites. This simple and low‐cost process leads to homogeneous microstructures with improved material properties compared with the state of the art in continuous fiber‐reinforced oxide/oxide composites. The developed composites in the present study exhibit favorable mechanical properties both at room temperature and after thermal aging for 1000 h at temperatures up to 1300°C.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Progress in Processing and Performance of Porous‐Matrix Oxide/Oxide Composites

Simon

2005

Int J Applied Ceramic Tech

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“…However, matrix microcracking and delamination may occur with increasing quenching temperature difference. [30] A further, very important property of Oxide Fiber Composites is their high-temperature long-term performance. Service temperatures above 1200 C are targeted considering gas-turbine applications.…”

Section: Resultsmentioning

confidence: 99%

Oxide Fiber Composites with Promising Properties for High‐Temperature Structural Applications

Simon

Dänzer

2006

Adv Eng Mater

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room temperature, resulting in mechanical collapse of the coating. This loss of mechanical integrity could also be promoted by massive internal oxidation of the CrN skeleton and, thus, formation of brittle Cr oxides. ConclusionsThe aim of this work was the verification of the high-temperature lubrication concept of CrN coatings containing Ag (Ag contents of 12 at.% and 22 at.%, respectively). As-deposited coatings show a phase-separated structure consisting of CrN and Ag grains with domain sizes of 15±25 nm and 5±10 nm, respectively. The friction coefficient against alumina at room temperature increases slightly from 0.4 to 0.5 with higher Ag contents. Also wear is pronounced in case of higher Ag contents, which is related to the lower hardness of these coatings. During annealing at 600 C, Ag agglomerates form on the coating surface and decrease the friction coefficient to 0.2 at the beginning of the test. With increasing sliding distance, the value increases to 0.40±0.44. This increase is attributed to fast out-diffusion of Ag and, in turn, a quick consumption of the lubricating phase. The remaining porous CrN skeleton lacks sufficient resistance to wear, causing the formation of abrasive debris and the rapid coating degradation after the Ag reservoir is exhausted.Finally, it can be concluded that alloying CrN coatings with Ag offers a high potential to enhance the tribological behavior in a wide temperature range and under varying environmental conditions, provided that the supply of the sliding contact with the Ag lubricant is controlled thoroughly.

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