Fracture in single-layer zirconia (YSZ)–bond coat alloy (NiCoCrAlY) composite coatings under thermal shock

2004 ◽  
Vol 52 (2) ◽  
pp. 455-465 ◽  
Author(s):  
Sudarshan Rangaraj ◽  
Klod Kokini
Metals ◽  
2014 ◽  
Vol 4 (4) ◽  
pp. 503-518 ◽  
Author(s):  
Torben Fiedler ◽  
Tatiana Fedorova ◽  
Joachim Rösler ◽  
Martin Bäker

2014 ◽  
Vol 602-603 ◽  
pp. 552-555
Author(s):  
Dan Lu ◽  
Ya Ran Niu ◽  
Xue Lian Ge ◽  
Xue Bing Zheng ◽  
Guang Chen

In this work, atmospheric plasma spray (APS) technology was applied to fabricate ZrC-W composite coatings. The microstructure of the composite coatings was characterized. The influence of W content on the ablation-resistant and thermal shock properties of ZrC-W composite coatings was evaluated using a plasma flame. The results show that the ZrC-W composite coatings had typically lamellar microstructure, which was mainly made up of cubic ZrC, cubic W and a small amount of tetragonal ZrO2. The ZrC-W coatings had improved ablation resistant and thermal shock properties compared with those of the pure ZrC coating. It was supposed that the improved density, thermal conductivity and toughness of the composite coatings contributed to this phenomenon.


2005 ◽  
Vol 492-493 ◽  
pp. 379-384 ◽  
Author(s):  
Klod Kokini ◽  
Sudarshan V. Rangaraj

The thermal fracture and its dependence on time-dependent behavior in functionally graded yttria stabilized zirconia - NiCoCrAlY bond coat alloy thermal barrier coatings was studied. The response of three coating architectures of similar thermal resistance to laser thermal shock tests was considered, experimentally and computationally.


2011 ◽  
Vol 275 ◽  
pp. 47-50
Author(s):  
Asma Salman ◽  
Brian Gabbitas ◽  
De Liang Zhang

Ti(Al,O)/Al2O3 and TiAl(O)/Al2O3 composite coatings have a potential to reduce dissolution and aluminium soldering tendency of H13 tool steel used in the aluminium processing industry. The thermal shock resistance of H13 tool steel coated with Ti(Al,O)/Al2O3 and TiAl(O)/Al2O3 composite powders sprayed using a high velocity oxygen fuel (HVOF) technique was studied. The thermal shock behaviour of the composite coatings was investigated by subjecting the coated coupons to a number of cycles, each cycle consisting of a holding time of 30 seconds in molten aluminium at 700 ± 10 °C followed by quenching into water. The surfaces of the coupons were examined for Al soldering and an evaluation of surface spallation. Any cracks found in the coatings were studied to explain their thermal shock behaviour. The results of this study showed that both Ti(Al,O)/Al2O3 and TiAl(O)/Al2O3 composite coatings on H13 tool steel have good thermal shock resistance with a thermal shock life between 300 to 400 cycles. The composite coatings and fracture surfaces were analyzed using scanning electron microscopy.


2014 ◽  
Vol 1058 ◽  
pp. 274-278
Author(s):  
Jun Guo Gao ◽  
Feng Lu ◽  
Meng Qiu Guo

Novel 4-phase ceramic abradable seal coatings have been prepared by plasma spray. The as-prepared coatings were characterized by SEM, EDS and XRD. The results showed that the 4-phase ceramic abradable coating exhibited porous structures and had good adhesion with the bond coat. The ZrO2 and Al2O3 in the coating existed in the form of tetragonal-ZrO2 and α-Al2O3, respectively. The result of thermal shock test revealed that compared with the 3-phase abradable coating, the thermal shock life of the 4-phase abradable coating had increased tenfold to 1900~2000 cycles from 100~200 cycles. The reason is owing to the reduction of oxygen partial pressure and thermal stresses at the top/bond coat interface due to the addition of the fourth nanoAl2O3 phase.


2018 ◽  
Vol 36 (2) ◽  
pp. 155-225 ◽  
Author(s):  
András Gergely

AbstractIn this review, most of the works are attempted to cover about corrosion protection of metals with molecular-tight atomic thin carbon layers of all sorts of graphene derivatives from the very beginning to the latest theoretical and experimental research findings, so as engineering achievements in the field up to date. Although high and tuneable electrical conductivity of graphene is the main feature exploited in majority of the applications such as catalysis, photocatalysis, electrocatalysis, low electrical but high chemical resistivity electrodes in batteries, and ultracapacitors, corrosion protection of metals favours the opposite – good physical separation and electrical insulation. Both of the latter ones lead to durable excellent protection, which can only be ensured by special design and implementation. Thus, the milestones of major hardships both on theoretical and practical sides are delineated similarly as utmost developments in circumventing all problems with an aim to ensure timely transfer from the research phase to successful industry utilisations. Relying on numerous works, this paper gives a comprehensive overview in the subjects of preparation, modification, and use of multiple sorts of graphene in the forms of neat, combined layers, and composite coatings on numerous metals. All performance parameters are given in detail. Chronological order of the article serves the purpose to give the reader a clear picture and an important clue on viability of strategies in the aspects of environmental friendliness, attainable maximum durability, and performance of corrosion protection with graphene films, as well as further advancements in the field expected to occur in the near future.


2019 ◽  
Vol 756 ◽  
pp. 237-247 ◽  
Author(s):  
Makoto Hasegawa ◽  
Maiko Iwashita ◽  
Yuji Kubota ◽  
Petr Dymáček ◽  
Ferdinand Dobeš

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