Cavitation Erosion Resistance of Silicified Graphite by Liquid Silicon Penetration Technique

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Hongqin Ding ◽  
Shuyun Jiang
Keyword(s):  
Cavitation Erosion ◽  
Erosion Resistance ◽  
Test System ◽  
Surface Microstructure ◽  
Chemical Compositions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sic Ceramic ◽  
Cavitation Erosion Resistance ◽  
Sem Morphology

This technical brief studied the cavitation erosion behavior of the silicified graphite. The phase constituents, surface microstructure, and chemical compositions of silicified graphite were examined by using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS), respectively. Cavitation experiments were carried out by using an ultrasonic vibration test system. The experimental results show that the silicified graphite exhibits an excellent cavitation erosion resistance; this can be attributed to the fact that the silicified graphite has the characteristics of both the silicon carbide and the graphite. The SEM morphology studies of the erosion surfaces indicated that the inherent brittleness of SiC ceramic material results in the formation of erosion pits on the surface of silicified graphite.

scholarly journals Cavitation Erosion Resistance and Wear Mechanism Model of Flame-Sprayed Al2O3-40%TiO2/NiMoAl Cermet Coatings

Coatings ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 254 ◽  
Author(s):  
Mirosław Szala ◽  
Tadeusz Hejwowski
Keyword(s):  
Cavitation Erosion ◽  
Erosion Resistance ◽  
Ceramic Powder ◽  
X Ray Diffraction ◽  
Low Velocity ◽  
Cermet Coatings ◽  
X Ray ◽  
Mechanism Model ◽  
Cavitation Erosion Resistance ◽  
Sprayed Coatings

This manuscript deals with the cavitation erosion resistance of flame-sprayed Al2O3-40%TiO2/NiMoAl cermet coatings (low-velocity oxy-fuel (LVOF)), a new functional application of cermet coatings. The aim of the study was to investigate the cavitation erosion mechanism and determine the effect of feedstock powder ratio (Al2O3-TiO2/NiMoAl) of LVOF-sprayed cermet coatings on their cavitation erosion resistance. As-sprayed coatings were investigated for roughness, porosity, hardness, and Young’s modulus. Microstructural characteristics of the cross section and the surface of as-sprayed coatings were examined by light optical microscopy (LOM), scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) methods. Coating cavitation tests were conducted in accordance with the ASTM G32 standard using an alternative stationary specimen testing method with usage of reference samples made from steel, copper, and aluminum alloys. Cavitation erosion resistance was measured by weight and volume loss, and normalised cavitation erosion resistance was calculated. Surface eroded due to cavitation was examined in successive time intervals by LOM and SEM-EDS. On the basis of coating properties and cavitation investigations, a phenomenological model of the cavitation erosion of Al2O3-40%TiO2/NiMoAl cermet coatings was elaborated. General relationships between their properties, microstructure, and cavitation wear resistance were established. The Al2O3-40%TiO2/NiMoAl composite coating containing 80% ceramic powder has a higher cavitation erosion resistance than the reference aluminium alloy.

Microstructure and Cavitation Erosion Behavior of Carbide-Based Coating Deposited by Electrical Arc Spraying

2011 ◽  
Vol 189-193 ◽  
pp. 498-502
Author(s):  
Sheng Hong ◽  
Yu Ping Wu ◽  
Hong Bin Sun ◽  
Yuan Zheng ◽  
Qi Fan Dai ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Mass Loss ◽  
Standard Method ◽  
Cavitation Erosion ◽  
Erosion Resistance ◽  
Arc Spraying ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electrical Arc ◽  
Cavitation Erosion Resistance

Two different martensite stainless steel 1Cr17/Carbide-based coatings (C-1 and C-2) were prepared by electrical arc spraying technique. Microstructures of the coatings were investigated by optical microscopy (OM), X-ray diffraction (XRD), scanning election microscopy (SEM). The results show that the C-2 coating has higher hardness and finer structure than the C-1 coating. The cavitation erosion resistance was tested using a China GB6383-86 standard method in fresh water. The cavitation erosion mass loss of the C-2 coating was only 55 percent that of the C-1 coating eroded 15h, the C-2 coating has better cavitation erosion resistance.

Cavitation Erosion Characteristics of an Iron-Based Coating Prepared by High Velocity Arc Spraying

2011 ◽  
Vol 189-193 ◽  
pp. 523-527
Author(s):  
Zhi Hua He ◽  
Yu Ping Wu ◽  
Hong Bin Sun ◽  
Yuan Zheng ◽  
Yu Dong ◽  
...  
Keyword(s):  
High Velocity ◽  
Cavitation Erosion ◽  
Erosion Resistance ◽  
Optical Microscope ◽  
Arc Spraying ◽  
X Ray Diffraction ◽  
High Velocity Arc Spraying ◽  
Iron Based ◽  
And Performance ◽  
Cavitation Erosion Resistance

In order to increase cavitation erosion resistance of fluid machinery, an iron-based coating was prepared by high velocity arc spraying (HVAS) on the surface of 1Cr18Ni9Ti stainless steel. The microstructure and performance were investigated respectively by optical microscope (OM), X-ray diffraction (XRD), scanning electron microscope (SEM), Vickers hardness and vibratory cavitation apparatus. The results indicated that the coating had the higher hardness (8.67GPa) and the finer structure than ZG230-450 (1.86GPa) used actual in water conservancy. Compared with ZG230-450, cavitation erosion resistance of the coating was better, and the coating presented flakiness stripping mode. The results indicated that the HVAS is a promising method to prepare the cavitation resistance coating.

scholarly journals Influence of TiO2 Additives on Cavitation Erosion Resistance of Al-Mg Alloy Micro-Arc Oxidation Coating

Coatings ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 521 ◽  
Author(s):  
Hongyan Jiang ◽  
Feng Cheng ◽  
Dianjun Fang
Keyword(s):  
Aluminum Alloy ◽  
Cavitation Erosion ◽  
Erosion Resistance ◽  
Ceramic Coatings ◽  
Chemical Compositions ◽  
Additive Concentration ◽  
Cavitation Damage ◽  
Short Period ◽  
Micro Arc Oxidation ◽  
Cavitation Erosion Resistance

Four ceramic coatings are fabricated on 6061 aluminum alloy substrates with a micro-arc oxidation technique in silicate electrolytes with different TiO2 nano-additive concentrations. To explore the cavitation erosion resistance of the micro-arc oxidation (MAO) coating, cavitation tests are performed using a vibratory test rig. After cavitation tests lasting 10 min, the mass losses, surface morphologies, and chemical compositions of the samples after cavitation tests are examined using a digital balance, scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS), respectively. The results indicate that, in contrast to the aluminum alloy, the MAO coatings, by adjusting TiO2 nano-additive concentration, can decrease the mean depth of erosion rate (MDER) due to the cavitation damage, and lead to an excellent cavitation erosion resistance. The results also show that: In contrast to aluminum alloy, MAO coatings can decrease the MDER due to the cavitation damage in a short period of time by adjusting TiO2 nano-additive concentration. With the increase of TiO2 nano-additive concentration, the compactness and the surface hardness of MAO coatings decrease, which can easily lead to larger erosion pits.

scholarly journals Microstructure and Cavitation Erosion Resistance of HVOF Deposited WC-Co Coatings with Different Sized WC

Coatings ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 307 ◽  
Author(s):  
Xiang Ding ◽  
Du Ke ◽  
Chengqing Yuan ◽  
Zhangxiong Ding ◽  
Xudong Cheng
Keyword(s):  
Fracture Toughness ◽  
Electron Microscope ◽  
Cavitation Erosion ◽  
Erosion Resistance ◽  
The Other ◽  
Fuel Spray ◽  
X Ray ◽  
Cavitation Erosion Resistance ◽  
Scanning Electron ◽  
Conventional Coating

Conventional, multimodal and nanostructured WC-12Co coatings with different WC sizes and distributions were prepared by high velocity oxy-fuel spray (HVOF). The micrographs and structures of the coatings were analyzed by scanning electron microscope (SEM), X-ray diffractometer (XRD) et al. The porosity, microhardness and fracture toughness of the WC-Co coatings were measured. The coating resistance to cavitation erosion (CE) was investigated by ultrasonic vibration cavitation equipment and the cavitation mechanisms were explored. Results show that there is serious WC decarburization in nanostructured and multimodal WC-Co coatings with the formation of W2C and W phases. The nanostructured WC-Co coating has the densest microstructure with lowest porosity compared to the other two WC-Co coatings, as well as the highest fracture toughness among the three coatings. It was also discovered that the nanostructured WC-Co coating exhibits the best CE resistance and that the CE rate is approximately one-third in comparison with conventional coating.

Cavitation Erosion Resistance of WC-Cr-Co and Cr3C2-NiCr Coatings Prepared by HVOF

2006 ◽  
Vol 15-17 ◽  
pp. 199-204 ◽  
Author(s):  
Ping Zhang ◽  
Jing Hua Jiang ◽  
Ai Bin Ma ◽  
Ze Hua Wang ◽  
Yu Ping Wu ◽  
...  
Keyword(s):  
Cavitation Erosion ◽  
Erosion Resistance ◽  
Optical Microscope ◽  
Hard Coatings ◽  
X Ray Diffraction ◽  
Coating Materials ◽  
And Performance ◽  
Cavitation Erosion Resistance ◽  
Microstructure And Performance ◽  
Better Than

With the aim to obtain the high cavitation-erosion-resistance coating for the surface safeguard of fluid machinery, two kinds of hard coatings (WC-Cr-Co and Cr3C2-NiCr) were prepared on 1Cr18Ni9Ti substrate by high velocity oxy-fuel spraying (HVOF), which microstructure and performance were investigated respectively by optical microscope, X-ray diffraction, Vickers hardness, scanning electron microscope (SEM), and vibratory cavitation apparatus. The results indicated that these two coatings had the higher hardness and the finer structure than ZG06Cr13Ni5Mo, which is used actual in water conservancy. The results of cavitation erosion continued for 39 hours presented that the mass loss of WC-Cr-Co and Cr3C2 -NiCr coatings increased ceaselessly with time, and the cavitation erosion speeds varied with time. Compared with ZG06Cr13Ni5Mo, their cavitation erosion resistance performances were better due to their higher hardness and finer structure, and WC-Cr-Co coating was much better than Cr3C2-NiCr coating. Obviously, the higher hardness and finer structure could strengthen the cavitation erosion resistance of coating materials.

Cavitation erosion resistance of a Co28Cr22Fe alloy.

2017 ◽  
Author(s):  
Juliana Barbarioli ◽  
André Tschiptschin ◽  
Cherlio Scandian ◽  
Manuelle Curbani Romero
Keyword(s):  
Cavitation Erosion ◽  
Erosion Resistance ◽  
Cavitation Erosion Resistance

scholarly journals New Insights into the Crystal Chemistry of Elpidite, Na2Zr[Si6O15]·3H2O and (Na1+YCax□1−X−Y)Σ=2Zr[Si6O15]·(3−X)H2O, and Ab Initio Modeling of IR Spectra

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2160
Author(s):  
Alexander Bogdanov ◽  
Ekaterina Kaneva ◽  
Roman Shendrik
Keyword(s):  
Ir Spectra ◽  
Structural Models ◽  
Chemical Characterization ◽  
Chemical Compositions ◽  
X Ray Diffraction ◽  
Special Group ◽  
X Ray ◽  
Influence Of Water ◽  
Radioactive Species

Elpidite belongs to a special group of microporous zirconosilicates, which are of great interest due to their capability to uptake various molecules and ions, e.g., some radioactive species, in their structural voids. The results of a combined electron probe microanalysis and single-crystal X-ray diffraction study of the crystals of elpidite from Burpala (Russia) and Khan-Bogdo (Mongolia) deposits are reported. Some differences in the chemical compositions are observed and substitution at several structural positions within the structure of the compounds are noted. Based on the obtained results, a detailed crystal–chemical characterization of the elpidites under study was carried out. Three different structure models of elpidite were simulated: Na2ZrSi6O15·3H2O (related to the structure of Russian elpidite), partly Ca-replaced Na1.5Ca0.25ZrSi6O15·2.75H2O (close to elpidite from Mongolia), and a hypothetical CaZrSi6O15·2H2O. The vibration spectra of the models were obtained and compared with the experimental one, taken from the literature. The strong influence of water molecule vibrations on the shape of IR spectra of studied structural models of elpidite is discussed in the paper.

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