Abstract:A yttrium-stabilised zirconia (YSZ) coating was prepared on Ti-6Al-4 substrates by electron beam physical vapour deposition (EB-PVD). The effect of substrate temperature and beam intensity on the microstructure of the coating was researched. Damping characteristics of the coatings under different processing parameters were compared. The microstructure and crystal structure were determined with scanning electron microscope (SEM) and X-Ray Diffraction (XRD), respectively. The damping properties of the coating we… Show more
“…It is evident that the coatings prepared using the different parameters primarily present a single phase. The diffraction patterns are in full agreement with the diffraction pattern of metastable tetragonal ZrO 2 (t ′ ) [22], which is formed from the quenching of molten droplets during plasma spraying at a rate of 10 6 K s −1 [23][24][25]. The XRD spectra of the coatings after thermal shock are also depicted in Figure 1(d).…”
Section: Characterization Of the Coatingssupporting
In this study, thermal barrier coatings with different porosities were prepared using 8 wt-% yttria-stabilized zirconia by atmospheric plasma spray on a superalloy substrate. The porosity of the ceramic coating was increased by modulating the primary gas flow rate and the secondary gas flow rate. The elastic modulus and fracture toughness of the coatings were measured by the indentation method, and the thermal shock resistance was evaluated by quenching the samples from 1050°C to room temperature. The Vickers hardness and elastic modulus of the coating were decreased by increasing the volume of the pores, and the fracture toughness was enhanced. It was found that the thermal shock resistance was improved owing to the stress release due to the pores.
“…It is evident that the coatings prepared using the different parameters primarily present a single phase. The diffraction patterns are in full agreement with the diffraction pattern of metastable tetragonal ZrO 2 (t ′ ) [22], which is formed from the quenching of molten droplets during plasma spraying at a rate of 10 6 K s −1 [23][24][25]. The XRD spectra of the coatings after thermal shock are also depicted in Figure 1(d).…”
Section: Characterization Of the Coatingssupporting
In this study, thermal barrier coatings with different porosities were prepared using 8 wt-% yttria-stabilized zirconia by atmospheric plasma spray on a superalloy substrate. The porosity of the ceramic coating was increased by modulating the primary gas flow rate and the secondary gas flow rate. The elastic modulus and fracture toughness of the coatings were measured by the indentation method, and the thermal shock resistance was evaluated by quenching the samples from 1050°C to room temperature. The Vickers hardness and elastic modulus of the coating were decreased by increasing the volume of the pores, and the fracture toughness was enhanced. It was found that the thermal shock resistance was improved owing to the stress release due to the pores.
“…The AZ coating developed at SOD of 75 mm exhibited highest damping capacity while AZ coating developed at SOD of 100 mm showed the least damping capacity (Figure 5(a) and Table 2). The superior damping behaviour is linked with higher porosity content as the porosities could act as shock-absorbing pockets in the microstructures [28,29]. Figure 5 Variation of loss tangent of both AZ coatings and bare substrate (i.e.…”
Alumina-25 wt-% zirconia (AZ) coatings were deposited on AISI304 stainless steel substrates by atmospheric plasma spraying (APS) technique with three different stand-off distances (SOD) namely, 75, 100 and 125 mm. X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques were utilized to study the phases and microstructures of the coatings, respectively. Surface roughness and percentage of open porosity of the coatings were also quantified by confocal laser scanning microscopy (CLSM) and SEM image analysis through Material Plus software, respectively. Finally, dynamic mechanical analyser (DMA) was employed for thorough investigation of the damping behaviours of the AZ coatings deposited at SODs conditions.
“…Alumina shows highest complex modulus whereas zirconia the lowest as expected. It is very important to notice that the complex modulus of A75Z25 is higher than that of A95Z5 which is possibly linked with higher micro-pores and cracks concentrations in A75Z25 which assists to enhance energy dissipation during loading [21,22]. Figure 3 Variation of (a) loss tangent and (b) complex modulus as a function of time.…”
Alumina and zirconia coatings along with three combinations of alumina-zirconia (AZ) composite coatings are deposited on AISI304 by atmospheric plasma spraying (APS) technique. The AZ coatings are developed on the alumina rich side by varying zirconia content (e.g. 5%, 15% and 25%). To investigate the phases , X-ray diffraction technique is utilized. Scanning electron microscopy technique is used to study the microstructures. The damping behaviors are studied by dynamic mechanical analyzer (DMA). It is observed that, zirconia has much better damping property than alumina and the damping capacity (i.e. tan δ) is increased with an increase in zirconia content in AZ coatings. However, it is interesting to note that the variation of complex modulus of AZ coating showed opposite trend as it showed in damping capacity. The damping capacities of all deposited coatings show a stable response over time and frequencies up to 60 Hz.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
