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Grey Cast Iron is widely used in manufacture of many automobile applications due to its low cost and performance. The applications include piston rings, cylinder liner, brake discs, etc. As they undergo friction, wear happens on the surface. Because of this wear the life of the components gets reduced. In order to avoid the wear of the components d...
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... substrate material identified is grey cast iron SAE G3500. Nominal Composition and Actual Composition of grey cast iron SAE G3500 is illustrated in Table 1. ...Similar publications
This work examines friction properties of smooth-honed thermal spray (TS) low carbon steel coatings produced on an Al-9.0% Si alloy using a plasma transferred wire arc (PTWA) method and an AISI 1010 wire used as feedstock in comparison with the ASM type D grey cast iron (CI) samples subjected to the same (smooth) honing process. CI samples prepared...
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... Moreover, at the interface the tightly adhering coating can be seen. It is the result of proper substrate preparation and reflects the advantages of the HVOF process, which is the high kinetic energy of the molten particles and/or highly plasticized powder particles [40,41]. It strengthens mechanical bonding between coating and substrate and improves adhesion. ...
The purpose of this work was to carry out comparative studies of WC-Co-Cr coatings deposited using the high velocity oxy fuel (HVOF) method onto two types of substrate material: structural steel S235 and magnesium alloy AZ31. The influence of the substrate material type on the microstructure, phase composition, crystallite size, porosity, Vickers microhardness, instrumental hardness (H IT ), Young’s modulus (E IT ), and fracture toughness was investigated. For both substrates, the deposited coatings deposited were characterized with fine-grained and compact microstructure. The X-ray diffraction (XRD) revealed presence of following phases: WC, W 2 C, Co 0.9 W 0.1 , and Co 3 W 9 C 4 . The WC phase was the most desirable and stable one with crystallites were below 100 nm. On the other hand, the size of the W 2 C crystallites was below 30 nm. The coatings obtained showed porosity values equal to 2.3 ± 0.4 vol% and 2.8 ± 0.7 vol% for AZ31 and S235, respectively. The average Vickers microhardness for both types of sample was appproximately 1200 HV0.3. The average H IT values for carbide particles and metallic matrix were around 29 GPa and 6.5 GPa, respectively. In the case of E IT , it was around 620 GPa and 190 GPa for WC and Co-Cr, respectively. The differences between coatings were negligible. The E IT value for both coatings was equal to 344 ± 11 GPa. The fracture toughness was around 4.5 MPa · m 1/2 in both cases. The investigations revealed that it is possible to replace steel substrate material with a much lighter equivalent, in this case AZ31 alloy, without deterioration of the coating properties.
... Successful applied to a broad grouping of materials, revealing minimal porosity, enhanced wear resistance, and increased hardness [15]. NiCrSiB coatings are often used where wear, oxidation, and hot opposition are required [16]. This is due to the coating's excellent mechanical [17], high temperature, tribological, and ecological effects [18]. ...
In the study high-velocity oxy-fuel thermal spraying to create Fe32Cr21Co21Al16Ti5B5 and Fe43Cr16Co12Al14Ti5B10, Fe32Cr21Co21Ni16Si5B5 and Fe43Cr16Co12Ni14Si5B10 coatings on Q235 steel substrates. Jet-type testing is used to examine the coatings’ resistance to slurry wear. Researchers examined the surface to learn more about the erosion process. Taguchi analysis and a wear model confirm the significance of the selected important factors. The wear model’s proposed mechanism shows remarkable agreement with the data. Coating loss may be attributed to several causes, including mixed ploughing, and cutting, platelet development, abrasion grooves, and cracking. The outcomes showed that the effect speed was the main contributing variable, the contribution ratio reached 65% to 70%, for the impact velocity of coating no 1 to 4. In contrast, it is recognized that impact velocity > impingement angle > erodent feed rate > erodent size is the most important sequence. Micro-cutting, mixed cutting, and ploughing were the essential disintegration systems for all coatings at low impingement points. In contrast, platelets were detected under normal impingement angles, as confirmed by SEM analysis. Both coatings seem to form passivation films, as shown by their greater Ecorr values relative to the substrate. Fe, Co, Cr, Al, and O all show up as peaks in XPS analyses.
... Хромовые покрытия на циркониевых сплавах также обеспечивают: − повышенную износостойкость (потеря массы образца в среднем в 5 раз меньше); − повышенную коррозионную стойкость в паре при 1200 °С (привес массы за 2 часа в 20 раз меньше); − пониженную водородопроницаемость: показано, что за 4 ч. окисления в паре при 1000 °С количество поглощённого водорода в сплав Zry-4 с покрытием 10 мкм Cr не превышает 80 ppm; показано, что количество водорода в образцах циркония (Zr) с хромовым покрытием после автоклавных испытаний (400 °С, 200 атм) уменьшается с 5,5 до 0,1 молекулы H2/г; − окисление по параболическому закону без наступления линейной стадии [8][9][10]. ...
In this paper, the theoretical research of Cr 3 C 2 -NiCr coating for zirconia substrate is discussed. To obtain this coating, one of the multi-efficiency methods high velocity oxygen-fuel thermal spraying (HVOF) was investigated. The coatings were processed by different thicknesses of zirconia substrate sample of 3–5 mm also with length of 20 mm and width of 30 mm, at spraying speed of 600–700 m/s. The temperature during HVOF spraying is about 3000 ºC and the cooling temperature is 27 ºC. Investigating the theoretical data of Cr 3 C 2 -NiCr coatings, the development and thermal stresses after HVOF treatment were determined using Stone's method and Brenner-Senderoff equations with a coating thickness not exceeding 0.6 mm for carbide coatings. According to the results of theoretical research, the deposition efficiency values were found by the method proposed by Kosaku Shinoda. According to the theoretical and mathematical calculations, the deposition efficiency for Cr 3 C 2 -NiCr coating with zirconia substrate is in the range of 59.5%–69.4%. Thus, it was found that the deposition efficiency for the coatings depends on the thickness of the substrate, the powder feed rate, and the mass of the applied material and consequently the number of spraying passes.
... Large numbers of surface coatings have been developed on different materials. Their wear and friction studies are reported [5,8,[14][15][16][17][18][19][20][21][22][23][24][25][26]. The authors also observed the superior properties of the coatings at elevated temperatures. ...
... The sliding wear and friction studies of Cr 3 C 2 -NiCr coatings deposited on the hot forming tool steels are still lacking. Sahraoui et al. [20], Murthy and Venkataraman [21], Shabana et al. [22], Shunmuga et al. [23], and Roy et al. [24] studied the wear behavior of Cr 3 C 2 -NiCr coatings deposited onto the surface of different substrates. The research was carried out at various temperatures. ...
Wear and surface damage of tools (die materials) in hot metal forming industry is a critical problem observed and is producing an adverse effect on the process economy. The problem occurs when tool and workpiece interact at higher temperatures. However, the research related to the wear and friction of dies is still lacking. In the present investigation, the tribological (wear and friction) studies were conducted with an aim to explore the potential of Cr3C2-NiCr surface coating. The coating was developed onto the surface of hot forming tool steel materials by the HVOF spray technique. The mechanical and physical properties of the coatings were determined. Subsequently, wear and friction studies were conducted utilizing a high-temperature tribometer at two different loads and at three temperatures. Specific wear rates and the average coefficient of friction values were evaluated. Wear mechanisms were studied by scanning electron microscopy (SEM) technique. The wear mechanisms were observed to be adhesive in nature at room temperatures and the combination of abrasive/oxidative/adhesive in nature at higher temperatures for the Cr3C2-NiCr coated specimens.
... As seen in Fig. 6, the friction coefficient and wear rate values of coatings were decreased with increasing the applied current density. The coefficient of friction is one of the effective parameters, which plays a critical role in the wear behavior of coatings [6,29,44]. It is obvious that the friction coefficient of coating prepared at a current density of 50 mA/cm 2 is much lower than that of sample prepared at a current density of 10 mA/cm 2 . ...
... The wear rate of prepared coating at a current density of 50 mA/cm 2 is lower than that of the sample prepared at a current density of 10 mA/cm 2 . Therefore, the tribological properties of the coatings were improved by decreasing the Fe and Ni contents, grain size reduction and increasing the co-deposition rate of Cr in the Fe−Ni matrix which are favored by increasing the applied current density [14,44]. This implies that the electroplated coating at a current density of 50 mA/cm 2 exhibits the best wear resistance ( Fig. 6(a)). ...
... By increasing hardness, real contact area between the abrasive pin and the surface of samples was decreased. This effect led to the decrease in the friction coefficient and wear rate [41,44,46]. Generally, based on these reasons, the hardness property was believed to be the dominating factor for reducing the friction coefficient and wear rate values. ...
The nanocrystalline Fe−Ni−Cr coatings were electrodeposited by using the pulse current technique. The SEM results showed that the coatings had a mixed morphology of small nodules and fine cauliflower structures at low current densities. Also, the Cr content was increased at expense of Fe and Ni contents at high current densities. XRD patterns confirmed that the pulse current density had a positive effect on the grain refinement. The results of vibrating sample magnetometer (VSM) measurements demonstrated that by increasing the current density, the saturation magnetization was decreased and the coercivity was increased due to the enhancement of Cr content and the reduction of the grain size. The friction coefficient and wear rate values were decreased by increasing the pulse current density. Also, both the adhesive and abrasive wear mechanisms were observed on the worn surfaces. The abrasive grooves and the amount of wear debris were decreased by increasing the pulse current density.
... Studies conducted by Demir et al. [92] and Samur et al. [93] discussed in Section 2.2.1 have also shown promising results for HVOF sprayed Cr 3 C 2 -NiCr coated brake disc in terms of lower wear rate and high corrosion resistance as compared to reference cast iron disc. Wear behavior of HVOF sprayed Cr 3 C 2 -NiCr coatings deposited on GCI discs was also studied by Priyan et al. [117]. Two different powder chemistries, viz. ...
Gray cast iron (GCI) is a popular automotive brake disc material by virtue of its high melting point as well as excellent heat storage and damping capability. GCI is also attractive because of its good castability and machinability, combined with its cost-effectiveness. Although several lightweight alloys have been explored as alternatives in an attempt to achieve weight reduction, their widespread use has been limited by low melting point and high inherent costs. Therefore, GCI is still the preferred material for brake discs due to its robust performance. However, poor corrosion resistance and excessive wear of brake disc material during service continue to be areas of concern, with the latter leading to brake emissions in the form of dust and particulate matter that have adverse effects on human health. With the exhaust emission norms becoming increasingly stringent, it is important to address the problem of brake disc wear without compromising the braking performance of the material. Surface treatment of GCI brake discs in the form of a suitable coating represents a promising solution to this problem. This paper reviews the different coating technologies and materials that have been traditionally used and examines the prospects of some emergent thermal spray technologies, along with the industrial implications of adopting them for brake disc applications.
... This process can also be used to reduce friction coefficient and the rates of wear to move parts. Nevertheless, grey cast iron coated with 80 % Cr 3 C 2 +20 %NiCr shows low friction coefficient because of its high carbide content [22]. The structure of WC-12Co coating applied on mild steel by HVOF thermal spray process shows better abrasive resistance rather than conventional coating [23]. ...
... The NiCr coating also shows fine, uniform, and layered microstructure [26] and sliding wear conditions. The lubrication decreases the COF formed because of the free carbon resulted from the decomposition of carbides and metal oxide debris during the sliding [22]. Furthermore, Ni-Cr-B-Si alloys have been used widely for protection from wear and corrosion of metallic parts as hardfacing alloys [27]. ...
In this paper, two excessive worn brake discs of a light commercial vehicle were coated with High velocity oxygen fuel (HVOF) thermal spray process for reuse. The coated discs were compared with uncoated Original equipment manufacturer (OEM) D1 disc in terms of braking performance and noise. The D2 disc was coated with tungsten-carbide-cobalt (88 %WC-12 %Co) powder and NiCr (80/20) binder, and 500 Gm thick coating was obtained. The D3 disc was coated with Colmonoy-88 (Ni-W-Cr-B-Si) powder and NiCr (80/20) binder and 600 Gm thick coating was obtained. Several test procedures (e.g. bedding, vibration, and structural-strength tests) was applied to three discs using inertia brake dynamometer. Results showed that coated D2 disc with tungsten carbide cobalt provided lower brake noise and higher brake performance compared with OEM disc. Considering the coefficient of friction and temperature, coated D3 disc has approximately equal braking performance with OEM D1 disc despite the high braking noise value.
Numerous mechanical parts, including, rotary vanes, emission and intake blowers, rotor rings, boiler tubes, steam turbines, gas turbines, pulverized fuel supply lines, nozzles, and gun barrels, are susceptible to erosive wear. Due to the simultaneous effects of various factors such as particle size, velocity, hardness, and impact angle, this erosive wear phenomenon is extremely complex. To alleviate the problems caused by erosion, several technical solutions have been proposed. Amongst these coatings are one such solution. The application of high-temperature coatings was found to be an efficient technique to reduce erosive wear in extreme environments. In recent years, many ceramic and metal coatings have both advantages and drawbacks. Therefore, it is crucial to discuss how different high-temperature coatings might enhance the erosive wear resistance. The technology development, influencing variables, properties, and failures of high-temperature erosion-resistant coatings are therefore highlighted in the current chapter. This could open up new opportunities for research into cutting-edge high-temperature erosive wear resistance coatings.
The microstructure, hardness and wear resistance of gray cast iron with detonation-sprayed Cr3C2 and Ni – Cr coatings are studied. It is shown that the Cr3C2 coating has stronger adhesion to the gray cast iron substrate and provides higher hardness and wear resistance than the Ni – Cr coating.
