scholarly journals Experimental Design of Solid Particle Wear Behavior of Ni-Based Composite Coatings

2021 ◽  
Vol 5 (5) ◽  
pp. 133
Author(s):  
Pragyan Senapati ◽  
Harekrushna Sutar ◽  
Rabiranjan Murmu ◽  
Shubhra Bajpai
Keyword(s):  
Experimental Design ◽  
Bond Strength ◽  
Wear Behavior ◽  
Composite Coatings ◽  
High Surface ◽  
Surface Hardness ◽  
Properties Of Coatings ◽  
Sem Images ◽  
The Impact ◽  
Scanning Electron

The composition of nickel-based metal matrix NiCrBSi was varied with 5%, 10% and 15% of Al2O3 particles to obtain high wear resistant coatings by means of a high-velocity oxy fuel (HVOF) thermal spraying process. The coating was characterized by optical microscope, scanning electron microscope (SEM) and X-ray diffractometer (XRD). The physical properties of coatings such as porosity, thickness, surface roughness, surface hardness, fracture toughness, bond strength and density were measured and compared. The experimental design of Taguchi L27 orthogonal array was employed to study and compare the effect of parameters such as impingement angle, impact velocity and alumina per cent in the coating on erosion. The coating containing 15 wt.% of Al2O3 and erodent speed of 33 m/s striking at inclination angle of 30° proved to be the best arrangement in preventing volume loss to a minimum of 0.00015 cc due to low-impact energy, high bond strength and high surface hardness. Analysis of variance (ANOVA) supported the assertion that the impact angle (A) of erodent and composition (C) were the factors contributing most to the volumetric loss as indicated by their combined effect A × C leading to the highest combined factor of 7.34. The scanning electron microscopy (SEM) images of the eroded coatings reveal that the mechanisms of erosion were the fracturing of splats, development of craters, micro cutting and ploughing action.

scholarly journals Thermal, mechanical and morphological properties of polyurethane–zirconia loading

2020 ◽  
Author(s):  
Ali J Salman ◽  
Ali Assim Al-Obaidi ◽  
Dalya H Al-Mamoori ◽  
Lina M Shaker ◽  
Ahmed A Al-Amiery
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Thermal Properties ◽  
Material Science ◽  
Morphological Properties ◽  
Flexural Stress ◽  
Renewable Materials ◽  
Sem Images ◽  
The Impact ◽  
Scanning Electron

Abstract The polyurethane (PU) has been showing a dramatic increase in applications related to material science and technology. However, the mechanical, physical and thermal properties could be further improved by loading PU with zirconia (Zr) to create renewable materials known as polyurethane–zirconia (PUZ) composites. In this study, PU matrix was treated with wt.% Zr at 0.5, 1.0, 1.5 and 2.0. In this study, the thermo-mechanical properties and the morphology were investigated of PU and PUZ nano-samples. The images of the scanning electron microscope (SEM) were the prime tool in investigating PU and PUZ surfaces and fractured surfaces showing vanishing the cracks and formation of agglomeration on the sample PUZ-1.5%. In addition, the tensile strength, Young’s modulus and maximum loading were improved by 36.7, 31.8 and 39.1%, respectively, at Zr loading of 1.5 wt.%. The flexural stress and the load were improved by 94.3% and 93.6%, respectively, when Zr loading was 1.5 wt.%. The impact without and with a notch was improved by 110.7% and 62.6%, respectively, at Zr loading of 1.5 wt.%. The the morphologies of the PU surface and Zr surface supported by SEM images. Regarding the storage modulus ability of PU and PUZ composites, Zr loading has negatively influenced E. The E functioning temperature was observed to move from 142 to 183°C. Another effect was determined by adding a small amount of Zr. This small amount was enough to shift the crystallization temperature (${T}_c$) and the melting temperature (${T}_m$) of PU from 125 to 129°C and from 150 to 144°C, respectively.

scholarly journals Effect of Tempering Temperature on Microstructures and Wear Behavior of a 500 HB Grade Wear-Resistant Steel

Metals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 45 ◽  
Author(s):  
Erding Wen ◽  
Renbo Song ◽  
Wenming Xiong
Keyword(s):  
Electron Microscopy ◽  
Wear Resistance ◽  
Impact Toughness ◽  
Wear Behavior ◽  
Temper Embrittlement ◽  
Surface Hardness ◽  
Resistant Steel ◽  
Tempering Temperature ◽  
Wear Resistant ◽  
The Impact

The microstructure and wear behavior of a 500 Brinell hardness (HB) grade wear-resistant steel tempered at different temperatures were investigated in this study. The tempering microstructures and wear surface morphologies were studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The relationship between mechanical properties and wear resistance was analyzed. The microstructure of the steel mainly consisted of tempered martensite and ferrite. Tempered troosite was obtained when the tempering temperature was over 280 °C. The hardness decreased constantly with the increase of tempering temperature. The same hardness was obtained when tempered at 260 °C and 300 °C, due to the interaction of Fe3C carbides and dislocations. The impact toughness increased first and reached a peak value when tempered at 260 °C. As the tempering temperature was over 260 °C, carbide precipitation would occur along the grain boundaries, which led to temper embrittlement. The best wear resistance was obtained when tempered at 200 °C. At the initiation of the wear test, surface hardness was considered to be the dominant influencing factor on wear resistance. The effect of surface hardness improvement on wear resistance was far greater than the impact toughness. With the wear time extending, the crushed quartz sand particles and the cut-down burs would be new abrasive particles which would cause further wear. Otherwise, the increasing contact temperature would soften the matrix and the adhesive wear turned out to be the dominant wear mechanism, which would result in severe wear.

Influence of Injection Conditions on the Mechanical Property of MWCNTs/ PC Nanocomposites

2014 ◽  
Vol 983 ◽  
pp. 94-98 ◽  
Author(s):  
Li Jun Wang ◽  
Jian Hui Qiu ◽  
Eiichi Sakai
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Mechanical Property ◽  
Bending Strength ◽  
Surface Hardness ◽  
Interfacial Interaction ◽  
Multiwalled Carbon ◽  
The Matrix ◽  
The Impact ◽  
Scanning Electron

The melting mixing was applied in the preparation of Multiwalled carbon nanotubes/Polycarbonate (MWCNTs/PC) nanocomposites. MWCNTs/PC nanocomposites with different MWCNTs contents were prepared under different injection conditions. The mechanical property of nanocomposites was comparatively investigated. The results demonstrated that: the tensile property of the nanocomposites was slightly improved by MWCNTs content increasing; but as the MWCNTs contents went on to increase to 10wt%, the tensile strength and bending strength were obviously decreased about 35% and 47%, respectively, but the impact strength and hardness were increased. The center hardness of MWCNTs/PC nanocomposites was greater than the surface hardness. Besides, the changes on the mechanical properties of the nanocomposites were studies by changing the injection conditions. By Scanning Electron Microscopy (SEM) observation, the microstructure and morphology of nanocomposites were analyzed, revealing that the center of the nanocomposite distributed more MWNTs, and the injection conditions would affect the MWNTs’ dispersion in the matrix and the interfacial interaction between MWCNTs and PC.

Study on the Subsonic Thermal Sprayed Ti/Bioglass Composite Coatings on Titanium Alloy

2005 ◽  
Vol 475-479 ◽  
pp. 2427-2430 ◽  
Author(s):  
Mu Qin Li ◽  
Da Shan Shang ◽  
Chen Ma ◽  
Shi Qin Yang
Keyword(s):  
Residual Stress ◽  
Titanium Alloy ◽  
Bond Strength ◽  
Composite Coatings ◽  
Thermal Spraying ◽  
Interface Layer ◽  
Heat Treated ◽  
Metallurgical Bond ◽  
Spraying Process ◽  
Scanning Electron

Ti/bioglass composite coatings on titanium alloy were prepared by a subsonic thermal spraying technology. Mixtures of titanium and bioglass powders with different proportions were used as feedstock. The effect of soaking of bioglass on the bond strength of between coatings and substrate was discussed. The bond strength and residual stress were investigated. The morphology was observed using scanning electron microscopy (SEM). The results showed that TiO2, CaTi4(PO4)6, CaTiO3, NaTi2(PO4)3 formed during thermal spraying process and the residual stress in the coatings was in compressive state. After the coatings were heat-treated, soaking of bioglass made some particles achieve metallurgical bond. Furthermore, new bioglass was formed and the compressive stress was increased. The phenomenon of bioglass healing up the cracks in the heat-treated coatings was observed through SEM, which reduced the porosity of the interface layer resulting in the significant increase of the bond strength.

scholarly journals Influence of Pre-Etched Area and Functional Monomers on the Enamel Bond Strength of Orthodontic Adhesive Pastes

2021 ◽  
Vol 11 (17) ◽  
pp. 8251
Author(s):  
Yuriko Tezuka ◽  
Yasuhiro Namura ◽  
Akihisa Utsu ◽  
Kiyotaka Wake ◽  
Yasuki Uchida ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Bond Strength ◽  
Shear Bond Strength ◽  
Functional Monomer ◽  
Gap Formation ◽  
Sem Images ◽  
Functional Monomers ◽  
Adhesive Remnant Index ◽  
Bovine Enamel ◽  
Scanning Electron

This study was performed to investigate the influence of pre-etching area and functional monomers in orthodontic adhesive pastes on enamel bond strength. Bovine enamel was partially pre-etched with phosphoric acid for 30 s over areas with a diameter of 1.0, 2.0 or 3.0 mm, and metal brackets were then bonded with or without functional monomers in the orthodontic adhesive paste. For the baseline groups, the whole adherent area was pre-etched. The shear bond strength (SBS) and adhesive remnant index (ARI) were determined. The adhesive paste/enamel interfaces were observed by scanning electron microscopy (SEM). Although the adhesive paste with functional monomers showed higher SBS than the functional monomer-free adhesive paste in all groups, there were no significant differences in SBS between them regardless of the pre-etched area. The SBS increased with increasing pre-etched area in both orthodontic adhesive pastes. In SEM images of adhesive paste/enamel interfaces, although adhesive with functional monomers showed excellent adaptation, the functional monomer-free adhesive paste showed gap formation at the interface. These findings suggested that the pre-etching area greatly influenced bond strength, regardless of the presence or absence of the functional monomer in the orthodontic adhesive paste.

scholarly journals Electroless Deposition of Composite Nickel-Phosphorous Coatings with Diamond Dispersoid

2016 ◽  
Vol 61 (2) ◽  
pp. 493-498 ◽  
Author(s):  
M. Petrova ◽  
M. Georgieva ◽  
V. Chakarova ◽  
E. Dobreva
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Chemical Composition ◽  
Electroless Deposition ◽  
Deposition Time ◽  
Composite Coatings ◽  
Flexible Substrates ◽  
Optimal Conditions ◽  
Sem Images ◽  
Scanning Electron

AbstractThe composite Ni-P coating with diamond particles (D) deposited on the flexible substrates of pressed polyethylene terephthalate material (PET) was obtained, to be used in the development of efficient, flexible grinding and polishing tools. The optimal conditions of the hydrodynamic regime, deposition time and temperature were found. The influence of the concentration and size of the D particles (3/7 ÷ 225/300 μm) on the coating thickness and number of co-deposited particles were studied. By Scanning Electron Microscopy (SEM) images were defined the morphology of dispersion coatings and number of co-deposited particles in them, and Energy Dispersive Spectroscopy (EDS/INCA) was used to determine the elemental chemical composition of the composite coatings.

scholarly journals Scanning Electron Microscopic Assessment of Stent Coating Integrity in Jailed Wire Technique for Bifurcation Treatment

2021 ◽  
Vol 2021 ◽  
pp. 1-5
Author(s):  
Lijian Gao ◽  
Ce Zhang ◽  
Huanhuan Wang ◽  
Yiqun Zhang ◽  
Zhan Gao ◽  
...  
Keyword(s):  
Fluid Model ◽  
Surface Damage ◽  
Side Branch ◽  
Electron Microscopic ◽  
Sem Images ◽  
Significant Difference ◽  
Stent Coating ◽  
The Impact ◽  
Scanning Electron

Objectives. To assess the impact of different guidewires on stent coating integrity in jailed wire technique (JWT) for bifurcation treatment. Background. JWT is commonly adopted to protect side branch in provisional one-stent strategy for coronary bifurcation lesions. However, this technique may cause defects in stent coatings. The degree of coating damage caused by different types of jailed wires remains unknown. Methods. A fluid model with a bifurcation was established to mimic the condition in vivo. One-stent strategy was performed with three types of guidewire (nonpolymer-jacketed wire, intermediate polymer-jacketed wire, and full polymer-jacketed wire) tested for JWT. Scanning electron microscopy (SEM) was used to evaluate stent coating integrity and wire structure. The degrees of coating defects were recorded as no, slight, moderate, and severe defects. Results. A total of 27 samples were tested. Analyses of SEM images showed a significant difference in the degree of coating damage among the three types of wire after the procedure of JWT ( P < 0.001 ). Nonpolymer-jacketed wire could inevitably cause a severe defect in stent coatings, while full polymer-jacketed wire caused the least coating damages. Besides, there were varying degrees of coil deformation in nonpolymer-jacketed wires, while no surface damage or jacket shearing was observed in full polymer-jacketed wires. Conclusions. Although nonpolymer-jacketed wire has long been recommended for JWT, our bench-side study suggests that full polymer-jacketed wire may be a better choice. Further clinical studies are needed to confirm our findings.

scholarly journals INFLUENCE OF MACRO- AND MICROSTRUCTURE OF STEEL GRINDING BALLS ON THEIR IMPACT RESISTANCE

2019 ◽  
Vol 62 (4) ◽  
pp. 283-289 ◽  
Author(s):  
A. A. Umanskii ◽  
A. V. Golovatenko ◽  
T. N. Oskolkova ◽  
A. S. Simachev ◽  
A. G. Shchukin
Keyword(s):  
High Surface ◽  
Impact Resistance ◽  
Experimental Studies ◽  
Surface Hardness ◽  
Central Zone ◽  
Complex Nature ◽  
Grinding Balls ◽  
Significant Difference ◽  
The Impact

Based on the analysis of the literature and production data, it is shown that the wear resistance of steel grinding balls, which are the main grinding medium for crushing various types of raw materials in the drum type mills, is determined not only by hardness of the surface layer, but also by the quality of their macro- and microstructure. At the same time, there is a complex nature of dependences of the balls impact resistance on the above mentioned parameters with their simultaneous impact, which determines the relevance of research in this direction. Series of experimental studies was carried out in order to obtain scientifically based dependencies of impact resistance of grinding balls on the quality of their macro- and microstructure. The grinding balls with a diameter of40 mm,50 mmand60 mmproduced by OJSC “EVRAZ ZSMK” (Novokuznetsk) and by JSC “Industrial Solutions” (Nizhny Tagil) were used. The research was carried out by metallographic, durometric and fractographic methods of analysis; tests of grinding balls on the impact resistance were performed on the impact drop machine. According to the results of metallographic studies it was determined that the volume-hardened balls are characterized by a three zone structure. The surface hardened layer with a depth from 1.9 to7.4 mmis martensite. The transition zone with thickness from 1.0 to1.7 mmhas a structure martensite + troostite. The central zone occupies the entire remaining volume of the ball and has several varieties of microstructure: ferrite + perlite, martensite + troostite + ferrite, martensite + troostite. On the basis of generalization of the obtained experimental data, it was established that at surface hardness of balls within 42 – 52 HRC the quality of macrostructure (presence of flakes) is the parameter determining impact resistance. For balls with high surface hardness (57 – 61 HRC) the most significant impact on impact resistance is provided by non-uniform microstructure of metal, which causes a significant difference in hardness across the balls crosssection.

An investigation of the impact of an amino-ended hyperbranched polymer as a new type of modifier on the compatibility of PLA/PBAT blends

2018 ◽  
Vol 38 (3) ◽  
pp. 223-229 ◽  
Author(s):  
Yujuan Jin ◽  
Shuang Men ◽  
Yunxuan Weng
Keyword(s):  
Fourier Transform ◽  
Hyperbranched Polymer ◽  
Poly Lactic Acid ◽  
Melt Mixing ◽  
Sem Images ◽  
Roller Mill ◽  
Elongation At Break ◽  
New Type ◽  
The Impact ◽  
Scanning Electron

AbstractPoly(lactic acid) (PLA)/poly(butylene adipate-co-terephthalate) (PBAT) blends using amino-ended hyperbranched polymers (HBP) as modifiers were prepared by melt-mixing through a double-roller mill and injection molding. It was found that when the content of HBP was 2.5 phr, the elongation at break and the impact strength of PLA/PBAT blends both reached peak values. Moreover, by addition of HBP, the ΔTg of the blends was smaller. These results, together with Scanning electron microscope (SEM) images on the fractured morphology of the blends, indicate that the compatibility between PLA and PBAT is improved upon addition of HBP. The mechanism of the impact of HBP on the improvement of the compatibility between PLA and PBAT is proposed based upon Fourier transform infrared (FTIR) spectra.

scholarly journals Impact-Sliding Tribology Behavior of TC17 Alloy Treated by Laser Shock Peening

2018 ◽  
Author(s):  
Meigui Yin ◽  
Wenjian Wang ◽  
Weifeng He ◽  
Zhenbing Cai
Keyword(s):  
Sliding Wear ◽  
Wear Behavior ◽  
Surface Hardness ◽  
Wear Test ◽  
Laser Shock Peening ◽  
Wear Testing ◽  
Laser Shock ◽  
Shock Peening ◽  
Multiple Impact ◽  
The Impact

Outer particles collision with certain dynamic object is not a pure impact wear behavior; it is typically accompanied by sliding wear phenomena. This study aimed investigating the impact-sliding wear performance of three different TC17 titanium alloys. One was untreated, and the other two were subjected to laser shock peening (LSP) by 5 and 7 J pulse energy, respectively. Wear test was performed on a novel impact-sliding wear testing rig, which can realize multiple impact-sliding motions by changing motion parameters in x and z directions. Present results showed that wear resistance of both treated samples improved compared with the untreated alloy. Given the increase in wear cycles, increment in wear rate of the untreated sample was constantly higher than those of treated samples. All results can be attributed to the increase in surface hardness of the material and residual compressive stress, which was also introduced after LSP.

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