Tribological and thermal characterization of electron beam physical vapor deposited single layer thin film for TBC application

Abstract

Thin-film coatings have been commonly used in the automotive industry for a variety of applications. Thermal barrier coatings (TBCs) are designed to extend the life of combustors and turbine blades while mitigating high-temperature issues. In this study, an attempt has been made to develop a singlelayer thin film as TBCs for engine applications. Yttria Stabilized Zirconia(YSZ) and Lanthanum Zirconate(LZ) were selected as the coating materials. The physical and chemical characteristics of target materials were studied using Scanning Electron Microscope (SEM), Energy Dispersive x-ray Spectroscopy (EDS), and x-ray Diffraction Analysis (XRD). FCD 400 has been taken as the substrates for this study. In general, TBCs thicknesses are usually about 100-300 μm, while in this work, a coating thickness of 750 nm is attempted using EB-PVD and its performance was evaluated. The mechanical, tribological, and thermal behaviors of the uncoated and coated substrates were characterized as per ASTM standards. Maximum hardness of 3.68 GPa was observed on the YSZ coated substrates. The average Coefficient of Friction (COF) and Coefficient of Thermal Expansion(CTE) values of YSZ coated substrates were 0.334 and 1.33×10 -5 K −1 , respectively, which were comparatively lower than LZ and uncoated substrates. On the contrary, the adhesive characteristics of YSZ and LZ coated substrates were enhanced, which was evident from their results of 6.28N and 6.19N respectively. The thermal conductivity of LZ coated substrates was found to be 3.2% lower than YSZ and 11% lower than uncoated substrates, respectively. From the results, it is observed that LZ thin film coating have better thermal properties than YSZ, which is best suited for TBCs application. Following evaluation of thin-film coatings, confirms that thin-film TBCs are a reliable approach for thermal and wear production as compared to thick TBCs, and their extended life could improve productivity and economic benefits for automotive industries.

Isothermal Oxidation TGO Growth Behaviors of Laser-Remolten LZO/YSZ Thermal Barrier Coatings

“…The most widely used ceramic coating is 6 wt.%~8 wt.% yttria partially stabilized zirconia (YSZ) for its high thermal expansion coefficient (11 × 10 −6 k −1 ), low thermal conductivity (2.1 W•m −1 •k −1 ), and satisfactory phase stability [6,7]. NiCoCrAlY is one of the most common choices for aero engine blade bonding coatings, because it not only improves the adhesion between the ceramic top layer and substrate, but also has excellent oxidation resistance and thermal resistance [8,9]. The TGO layer, which usually consists of a continuous dense Al 2 O 3 layer and mixed-oxides layer [10][11][12], is formed during the bonding coating oxidation because oxygen continuously passes through the ceramic coating in the TBC high-temperature service process.…”

Prevalence of Oral Screen Appliance Therapy in 6-12 Year Old Children Visiting a University Dental Hospital: A Retrospective Study

“…It is believed to strengthen the lips in the regular application of external force with accompanying lip contraction; that is to say, the lips will be able to exercise more force as a result of their training [14]. Our team has extensive knowledge and research experience that has translate into high quality publications [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30].…”

Prevalence of dental trauma and its association with gender among age group of 2-6 year

“…So this research is used to obtain information on the amount and to know types of dental trauma that occur in children between the age group of 2-6 years. Our group has broad information and exploration experience that has converted into great distributions (13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25) (26)(27)(28)(29)(30)(31)(32).The aim of the current study is to assess the prevalence of dental trauma and its association with gender among age groups of 2-6 years.…”