Influence of structural parameters on abrasion-erosion resistance of various repairing mortars

1990 ◽  
Vol 17 (1) ◽  
pp. 12-18 ◽  
Author(s):  
J. Mirza ◽  
S. Turenne ◽  
J. Masounave
Keyword(s):  
Erosion Resistance ◽  
Incidence Angle ◽  
Structural Parameters ◽  
Hydraulic Structures ◽  
Slurry Erosion ◽  
Large Size ◽  
Factors Influencing ◽  
Strong Relation ◽  
Sand Particles ◽  
Repair Mortars

Slurry erosion tests were performed on various types of repairing mortars in order to determine the factors influencing the abrasion-erosion resistance of some mortars. An in-house built apparatus was used, which produced a slurry jet that impinged the surface of mortar specimens with an incidence angle of 45° and a velocity of 18.5 m/s. The results showed that the epoxy mortars were the most erosion resistant compared with cementitious grouts and polymer-modified cement-based mortars. The erosion of mortars is controlled by the wear of the binder (epoxy or cement paste), and a strong relation exists between the erosion resistance of the mortar and the absence of microporosity in the binder. The results also suggest that to minimize the exposed areas of the binder, well-graded, i.e., small- and large-size, sand particles should be used. Key words: abrasion, erosion, repair mortars, cementitious grouts, polymer-modified cement-based mortars, epoxy mortars, hydraulic structures.

Fabrication of large UV transmission blazed gratings for slitless spectral sky survey

2022 ◽  
Vol 21 (12) ◽  
pp. 307
Author(s):  
Zhi-Wen Chen ◽  
Mao-Qi Cai ◽  
Ke-Qiang Qiu ◽  
Ya-Nan Wang ◽  
Huo-Yao Chen ◽  
...  
Keyword(s):  
Structural Parameters ◽  
Ion Beam ◽  
Stray Light ◽  
Narrow Slit ◽  
Ion Beam Etching ◽  
Blazed Grating ◽  
Large Size ◽  
International Astronomical ◽  
Sky Survey ◽  
Photoresist Mask

Abstract Slitless spectral sky survey is a critical direction of international astronomical research. Compared with ground-based sky survey, space-based sky survey can achieve full-band observation, and its imaging quality and resolution capability are restricted by the efficiency and size of dispersive elements. Transmission blazed gratings are often used as the dispersive elements in the UV band. Holographic interference lithography produces the photoresist mask of a grating, and the ion beam etching vertically transfers the pattern to the substrate to form the SiO2 mask of a grating. To reduce the effect of ion beam divergence on the uniformity of the groove shape, the grating mask is etched tilted by the ion beam passing through a narrow slit to obtain a blazed grating with consistent structural parameters. Moreover, two-dimensional scanning of the sample stage enables the etching of large-size samples. A UV transmission blazed grating with a linear density of 333 lines mm−1, a blazing angle of 11.8°, and a dimension of 99.2mm × 60.0mm × 6.0mm was successfully fabricated with an average diffraction efficiency of 66%, a PV diffraction wavefront of 0.169λ (λ = 632.8 nm) and low stray light.

scholarly journals Design and Fabrication of Moth-Eye Subwavelength Structure with a Waist on Silicon for Broadband and Wide-Angle Anti-Reflection Property

Coatings ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 360 ◽  
Author(s):  
He Lin ◽  
Mingzhao Ouyang ◽  
Bingxu Chen ◽  
Qifan Zhu ◽  
Jinshuang Wu ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Incidence Angle ◽  
Structural Parameters ◽  
Diffraction Order ◽  
Wide Angle ◽  
Subwavelength Structure ◽  
Inductively Coupled ◽  
Beam Laser ◽  
Interferometric Lithography ◽  
Rigorous Coupled Wave

Reflection loss on the optical component surface is detrimental to performance. Several researchers have discovered that the eyes of moths are covered with micro- and nanostructured films that reduce broadband and wide-angle light reflection. This research proposes a new type of moth-eye subwavelength structure with a waist, which is equivalent to a gradient refractive index film layer with high–low–high hyperbolic-type fill factor distribution. The diffraction order characteristics of a moth-eye subwavelength structure are first analyzed using a rigorous coupled wave analysis. The moth-eye structural parameters are optimized within the spectral range of 2–5 μm using the finite-difference time-domain method. The experimental fabrication of the moth-eye structure with a waist array upon a silicon substrate is demonstrated by using three-beam laser interferometric lithography and an inductively coupled plasma process. The experimental and simulation results show good agreement. The experimental results show that the reflectivity of the moth-eye structure with a waist is less than 1.3% when the incidence angle is less than 30°, and less than 4% when the incidence angle is less than 60°. This research can guide the development of AR broadband optical components and wide-angle applications.

Synergistic effect of Al2O3/TiO2 reinforcements on slurry erosion performance of nickel-based composite coatings

2017 ◽  
Vol 232 (8) ◽  
pp. 974-986 ◽  
Author(s):  
Rajeev Kumar ◽  
Sanjeev Bhandari ◽  
Atul Goyal
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Mass Loss ◽  
Erosion Resistance ◽  
Slurry Erosion ◽  
Specific Mass ◽  
Operational Parameter ◽  
X Ray ◽  
Specific Mass Loss ◽  
Scanning Electron

Various aspects such as development, experimentation, and analysis have been covered in the present work to examine the behavior of test coatings under slurry erosion. The primary objective of the present study was to establish the specific mass loss from the test coatings under various slurry environmental conditions and highlights the importance of the addition of alumina in improving the slurry erosion resistance of Ni-TiO2 coating. To attain this objective, two powder compositions, viz. Ni-20TiO2 and Ni-15TiO2-5Al2O3 were deposited onto the CA6NM grade hydro-turbine steel using high velocity frame spray process. The microstructural characterization of the coatings was done by employing surface roughness tester, scanning electron microscope/energy-dispersive X-ray spectroscopy, and X-ray diffraction techniques, whereas mechanical analysis was carried out using micro-hardness and bond strength tester. The slurry erosion tests were performed using an indigenously fabricated high speed slurry erosion test rig at different levels of rotational speed, average particle size of erodent, and slurry concentration in order to explore their effects on slurry erosion performance of test coatings. The slurry erosion results, as well as scanning electron microscope observations of eroded specimens, revealed higher slurry erosion resistance of Ni-15TiO2-5Al2O3 coating in comparison with Ni-20TiO2 coating. Furthermore, each operational parameter was found to have a proportional effect on specific mass loss in case of both the coatings.

Investigating Opto-Electronic Properties of Surface Plasmon Structure for Spectroscopic Applications

2019 ◽  
pp. 216-276
Author(s):  
Pratibha Verma ◽  
Arpan Deyasi
Keyword(s):  
Surface Plasmon ◽  
Incidence Angle ◽  
Structural Parameters ◽  
Metal Layer ◽  
Damping Ratio ◽  
Characteristic Impedance ◽  
Field Enhancement ◽  
Wavelength Dependence ◽  
Allowable Limit ◽  
Layer Medium

This chapter is proposed with an approach to analyze reflectance as a function of negative index material thickness for different parameters under the surface plasmon condition and extended approach towards the field enhancement of electric field as function of incidence angle and transmittance as function of incidence angle has been analyzed. This chapter can reflect the good comparison between 3 layer medium and n layer medium model. Characteristic impedance of MIM surface plasmon structure is analytically calculated considering the effect of both Faraday inductance and kinetic inductance. Effect of metal layer thickness, insulator thickness, and electron density are tailored to observe the impedance variation with frequency. Wavelength dependence of characteristic impedance and quality factor of MIM (metal-insulator-metal) surface plasmon structure is analyzed. Structural parameters and damping ratio of the structure is tuned within allowable limit to analyze the variation after detailed analytical computation.

Slurry Erosion Behaviors of Pseudoelastic TiNi Alloy

2007 ◽  
Author(s):  
Renbo Xu ◽  
Lishan Cui ◽  
Yanjun Zheng ◽  
Siwei Zhang
Keyword(s):  
Stainless Steel ◽  
Erosion Resistance ◽  
Deformation Mode ◽  
Experimental Results ◽  
Material Surface ◽  
Tini Alloy ◽  
Erosion Process ◽  
Slurry Erosion ◽  
Pile Up ◽  
The Impact

The slurry erosion behaviors of pseudoelastic TiNi alloy were studied using the liquid/solid impingement system and compared with SUS 630 and 2Cr12NiMo1W1V alloy. The influences of erosion time and angle on erosion resistance of three materials were surveyed. The experimental results show that TiNi alloy has the highest erosion resistance among the three materials and SUS 630 stainless steel is more resistant than 2Cr12NiMoW1V alloy. The KQL-300 indentation tester was used to simulate the impact of particle on material surface during erosion process. The results show that the deformation mode of indention can be pile-up or sink-in and there is a good correlation between erosion resistance of material and its indentation deformation mode. The sink-in deformation mode indicates the higher resistance to erosion, and the pile-up deformation mode implies the lower erosion resistance.

Slurry Erosion Performance of Ni + B4C Microwave Composite Clads

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
M. Minhaj ◽  
Bhupinder Singh ◽  
Sunny Zafar
Keyword(s):  
Alloy Powder ◽  
Erosion Resistance ◽  
Steel Substrate ◽  
Microstructural Characterization ◽  
Impact Angle ◽  
Slurry Erosion ◽  
Carbide Phases ◽  
Erosion Test ◽  
Microwave Hybrid Heating ◽  
Resistance Performance

Abstract A composite clad of Ni-based alloy and B4C was developed on austenitic steel substrate through microwave hybrid heating. The B4C was added with Ni-based alloy powder in various weight proportions (0%, 5%, 10%, and 20%). The clads were investigated for the microstructural details, nanohardness and slurry erosion performance. Silt collected from river Uhl was used as the erodent for the slurry erosion test. Slurry erosion performance of the clads was evaluated at an impact angle of 90 deg and jet velocity of 40 m/s. Microstructural characterization confirms the uniform distribution of hard (boride and carbide) phases in the Ni-based matrix of the microwave composite clads. The presence of hard phases in the Ni-based matrix enhanced the slurry erosion resistance performance.

Influence of Power on Interplay of Microstructure and Erosion-Tribo Performance of Microwave Composite Clads

2020 ◽  
Vol 142 (11) ◽  
Author(s):  
Bhupinder Singh ◽  
Sunny Zafar
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Metal Matrix Composite ◽  
Matrix Composite ◽  
Microwave Power ◽  
Metal Matrix ◽  
Erosion Resistance ◽  
Phase Evolution ◽  
Slurry Erosion ◽  
Microwave Cladding

Abstract Metal matrix composite (MMC) clads were developed through microwave cladding technique on CA6NM substrate using different microwave power levels. The influence of microwave power was investigated on the microstructure, phase evolution, mechanical properties, and erosion-tribo performance of the clad layers. Increase in microwave power resulted in reduction of Cr7C3 phase in clad layers, which eventually decreases the fracture toughness and microhardness of the clad. Clad fabricated at 600 W exhibited highest fracture toughness (11.6 ± 0.58 MPa√m) and microhardness (949 ± 47.45 HV). All clads exhibited highest erosion at 60 deg indicating a mixed erosion mode. Clads fabricated at power levels beyond 600 W, with less Cr7C3 content exhibited severe carbide pullout, thus deteriorated the slurry erosion resistance of the clads.

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