Search results for "substrate"
showing 10 items of 1018 documents
Quantification of Plasma Sprayed Coating Adhesion Using Pulsed Laser Induced Decohesion Technique
2001
Abstract The aim of the present study is to compare a laser ultrasonic technique with a conventional indentation test for the determination of intrinsic properties and the adhesion of alumina coatings, of different thicknesses (30–350 µm), deposited on stainless steel substrates by atmospheric plasma spraying (APS). For this purpose, a pulsed Nd:YAG laser is used to irradiate the coated specimens, and the ultrasonic waves generated by the laser are recorded at the epicenter using a laser interferometer. In the thermoelastic regime, the good agreement between the experiment and computation allows determination of the longitudinal wave velocity as well as the Young's modulus of the oxide coat…
Hardness and modulus of elasticity of atomic layer deposited Al2O3-ZrO2 nanolaminates and mixtures
2020
This work was funded by the European Regional Development Fund project TK134 “Emerging orders in quantum and nanomaterials”, Estonian Research Agency project PRG4 “Emerging novel phases in strongly frustrated quantum magnets”.
PEMBUATAN SISTEM VAKUM OTOMATIS GAS H2S BERBAHAN TiO2-Ni/Al2O3 TERKONEKSI ARDUINO UNO PADA LABORATORIUM KIMIA
2021
Research has been carried out on the H2S gas sensor made of TiO2-Ni/Al2O3 which is connected to an automatic vacuum. The results showed that the optimum conditions for the variation of Ni doping metal levels were 20 mg / gram TiO2. The semiconductor material synthesis method used the sol gel method with TTiP precursor which was made at pH 7. Coating of the sol gel solution on the Al2O3 substrate used a dip coater with a decrease speed of 1 cm / minute and was carried out 7 times of immersion. The characterization of synthetic results used UVVis, XRD, FTIR and SEM-EDX. The band gap value resulting from Ni doping is 2.75 eV from 3.2 eV, XRD identification shows that TiO2 is anataseic and dete…
Microhardness and adhesion measurements of reactively sputtered TiN/AlN multilayer coatings deposited as function of mass-flow of nitrogen
1998
Abstract Multilayer coatings of (Ti, Al)N x have been deposited by reactive sputtering from Ti and Al targets in a side-by-side configuration on WC and stainless steel substrates. The rotation of the substrate holder varied from 2 to 14 r.p.m. corresponding to a bilayer thickness of 0.8–8 nm. The acoustic emission scratch technique for adhesion measurements was used for studying coating performance, and critical load values for the coatings on WC substrate up to 150 N were obtained. The Vickers microhardness in the load range 0.003–2 N was measured, and in order to obtain true hardness values, an optimal range of indentation depth and coating thickness was determined. Depending on the nitro…
A comparative study of Ag and Cu adhesion on an MgO(001) surface
2004
Abstract Ab initio calculations were performed on 2D slab models of copper and silver adhesion on a perfect MgO(001) surface using density functional theory (DFT) combined with the localized atomic wave functions, as implemented in both CRYSTAL-98 and CRYSTAL-03 computer codes. To clarify the nature of the interfacial bonding, we consider slab models of the Ag/MgO(001) and Cu/MgO(001) interfaces with six different substrate coverages, varied from 1 4 monolayer (ML) up to 2 ML. The dependence of several key interface properties on the substrate coverage is analyzed. For all coverages, the most favorable sites for the adsorption of metal atoms are found to be above the surface O 2− ions, wher…
Enhanced thermoelectric properties of lightly Nb doped SrTiO3 thin films
2021
Novel thermoelectric materials developed for operation at room temperature must have similar or better performance along with being as ecofriendly as those commercially used, e.g., BiTe, in terms of their toxicity and cost. In this work, we present an in-depth study of the thermoelectric properties of epitaxial Nb-doped strontium titanate (SrTiNbO) thin films as a function of (i) doping concentration, (ii) film thickness and (iii) substrate type. The excellent crystal quality was confirmed by high resolution transmission electron microscopy and X-ray diffraction analysis. The thermoelectric properties were measured by the three-omega method (thermal conductivity) and van der Pauw method (el…
Reconstitution of a protein monolayer on thiolates functionalized gaas surface
2012
International audience; In the aim to realize an efficient resonant biosensor, gallium arsenide (GaAs) presents many advantages. In addition to its properties of transduction, GaAs is a crystal for which microfabrication processes were developed, conferring the possibility to miniaturize the device and integrate electronic circuit. Moreover, the biofunctionalization could be realized on the crystalline surface without layer deposition, constituting a real advantage to perform reusable sensor. The functionalization of GaAs surface was engaged in order to immobilize a protein monolayer on this substrate. Functionalization was done using a mixed self assembled monolayer of thiolate molecules. …
Experimental evidence of high spatial confinement of elastic energy in a phononic cantilever
2021
We report on experimental high spatial confinement of elastic energy in a silicon phononic cantilever for which the quality factor of a higher-order flexural resonance is increased by a factor of 27 (from Q ∼ 80 to Q ∼ 2130) with the use of a three-row phononic crystal (PnC) strip. As shown by numerical simulations performed with the finite element method, the PnC both reduces anchor loss and confines elastic energy inside the cantilever. The PnC and the cantilever are fabricated with standard clean room techniques on a silicon on insulator substrate. Optical measurements of the out-of-plane displacements are performed with a laser scanning interferometer in a frequency range around 2 MHz.
Thermal Characterization of the Chip-Tool Interface When Using Coated Turning Inserts
2000
Abstract This paper reports some results of extensive experimental investigations of the thermal interactions between the coating/substrate and the moving surface of the chip. Semi-orthogonal cutting when bar turning a medium carbon steel and an austenitic stainless steel was carried out. Both flat-faced and grooved inserts coated with TiC, TiC/TiN, and TiC/Al 2 O 3 /TiN were tested. A standard K-type thermocouple embedded in the workpiece was used to convert measured efm's to the interfacial temperatures. In addition, the chiprake contact length and the area of contact were determined by using computer processing of scanned contact images. The minimum steady-state temperature at the interf…
Highly Active Hydrogenation Catalysts Based on Pd Nanoparticles Dispersed along Hierarchical Porous Silica Covered with Polydopamine as Interfacial G…
2020
New catalysts based on Pd(0) nanoparticles (Pd NPs) on a bimodal porous silica of the UVM-7/polydopamine (PDA) support have been synthesized following two preparative strategies based on the sequential or joint incorporation of two components of the composite (Pd and PDA). We analyzed the role played by the PDA as &lsquo