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The purpose of this paper is to investigate the combined erosion and corrosion behavior of WC-Ni vacuum brazed coating.

Al₂O₃ particles and 10 wt% NaCl solution are used to evaluate erosion and corrosion resistance of WC-Ni vacuum brazed coating. Combined test of erosion and corrosion is also conducted. The microstructure of each specimen is characterized by the scanning electron microscopy. The chemical composition was determined by energy-dispersive X-ray spectroscopy.

WC-Ni vacuum brazed coating layer is effective protective coating under combined erosion and corrosion environment. The weight loss of coating layer is more reduced as the cumulative test time.

WC-Ni vacuum brazed coatings are investigated to check characteristic of the combined erosion and corrosion environment. WC-Ni vacuum brazed coatings are kind of diffusion coating that attract attention because of the resistance of superb impact and corrosion in comparison with other coatings. Some previous researches reported the properties of vacuum brazed WC material. Erosion and corrosion behaviors of WC-Ni vacuum brazed coatings were studied in our previous research, respectively. Hence, in this research, the principal objective is to examine the combined erosion and corrosion behavior of WC-Ni vacuum brazed coating.

This paper aims to clarify the relationship between the slurry erosion and one of the case hardening treatments, i.e. boronizing in this study, for AISI-5117 steel alloy. AISI-5117 steel alloy was used because of its variety applications in the field of submarine equipment. Most of the slurry erosion factors such as velocity, impact angle and mechanism of erosion were studied at different impact angles.

At first, the samples were prepared and subjected to the boronizing treatment in controlled atmosphere. By using a slurry erosion test-rig, all experiments for studying the slurry erosion factors were carried out. Moreover, the studied specimens were investigated via scanning electron microscope, optical microscope and X-ray diffraction to study the erosion mechanism in the different conditions.

It was expected that the boronization of the AISI-5117 steel would increase its slurry erosion resistance due to its positive impact on the surface hardness. However, the results observed show the opposite, where the boronization of AISI-5117 steel decreased its slurry erosion resistance as implied by the increase of the mass loss percentage at all impact angles.

This research, for the first time, exhibits the effect of boronizing treatment on the slurry erosion in different impact factors accompanied by the erosion mechanism at each impact angle.

The purpose of this paper is to investigate the erosion performance of high velocity oxy fuel- (HVOF) sprayed Al₂O₃–Cr₂O₃ composite coatings under silt slurry conditions.

The requisite HVOF composite coatings has been deposited on the stainless steel substrate (SS-304). The slurry erosion pot tester of make Ducom was used for conducting the silt slurry erosion tests on the required substrates. The comprehensive experiments were conducted at different particle size of silt in the range 212–250, 150–212, 53–106 µm, and the concentration of the silt ranged from 10%–40% by weight. The rotational speed of the pot tester has been varied between 500 and 1,500 revolutions per minute, and the test duration has been kept to 4 h.

The erosion wear resistance of the uncoated SS-304 has been greatly enhanced by the application of HVOF-sprayed Al₂O₃–Cr₂O₃ composite coatings. The addition of CeO₂ has a significant impact in reducing the erosive wear caused by silt slurry. The composite coating powder composition of 65%Cr₂O₃ + 34.5%Al₂O₃ + 0.5%CeO₂ has shown the highest erosion resistance.

The developed coatings have the potential to be used for hydro turbines as subjected to silt slurry conditions.

The erosion wear experiments are conducted comprehensively for coated and uncoated samples and the scanning electron micrographs supports the findings.

The paper's aim is to investigate the sand slurry erosive wear behaviour of Ni‐Cr‐Si‐B coating deposited on mild steel by flame spraying process under different test conditions.

Flame sprayed coatings of Ni‐Cr‐Si‐B were developed on mild steel substrate The slurry pot tester was used to evaluate wear behaviour of the coating and mild steel. The erosive wear test was conducted using 20 and 40 per cent silica sand slurry at three rotational speeds (600, 800 and 1,000 rpm).

Slurry erosive wear of the coating showed that in case of 20 per cent silica sand slurry weight loss increases with increase in rotational speed from 600 to 1,000 rpm while in case of 40 per cent silica sand slurry weight loss first increases with increase in rotational speed from 600 to 800 rpm followed by marginal decrease in weight loss with further increase in rotational speed from 800 to 1,000 rpm. Increase in wear resistance due to thermal spray coating of Ni base alloy on mild steel was quantified as wear ratio (weight loss of mild steel and that of coating under identical erosion test conditions). Wear ratio for Ni‐Cr‐Si‐B coating was found in range of 1.4‐2.8 under different test conditions. The microstructure and microhardness study of coating has been reported and attempts have been to discuss wear behaviour in light of microstructure and microhardness. Scanning electron microscope (SEM) study of wear surface showed that loss of material from the coating surface takes place by indentation, crater formation and lip formation and its fracture.

It would assist in estimating the erosion wear performance of flame sprayed Ni‐Cr coatings and their affects of wear resistance.

Erosion wear of flame sprayed coatings in sand slurry media medium is substantiated by extensive SEM study.

This paper aims at erosion wear experimentation conducted on two piping materials, namely SS202 and SS304 to establish the effect of rotational speed, concentration and time period.

Erosion wear because of slurry flow is investigated using a slurry erosion pot tester. Fly ash is taken as erodent material having different solid concentrations lie in range 30 to 60per cent (by weight). Experiments are performed at four different speeds, i.e. 600; 900; 1,200; and 1,500 rpm for time duration of 90, 120, 150 and 180 min, respectively. To enhance erosion wear resistance of both piping materials, high-velocity-oxy-fuel coating technique is used to deposit WC-10Co4Cr coating. The parametric influence of erosion wear is optimized using Taguchi method.

The results show that significant improvement in erosion wear resistance is observed by deposition of WC-10Co4Cr coating. It is observed that rotational speed is found as highly influencing parameter followed by concentration and time duration. Parametric investigation of erosion wear is helpful to develop a procedure for minimizing the erosion wear in pipeline for the flow of solid-liquid mixture.

Slurry erosion wear of WC-10Co4Cr coated stainless steel (SS202 and SS304) is substantiated by extensive microstructural analysis and optimization technique.

This paper aims to cover all the aspects of development, investigation and analysis phases to evaluate the slurry erosion performance of test coatings. The powders having composition of Ni-20Al₂O₃ and Ni-15Al2O₃-5TiO₂ were deposited on CA6NM grade turbine steel by using high velocity flame spray (HVFS) technique. The characterization of the coatings was done with the help of SEM/EDS and XRD techniques. Various properties such as micro-hardness and bonding strength of the coatings were also evaluated. Thereafter, these coatings were subjected to an indigenously developed high speed slurry erosion tester at different levels of rotational speed, erodent particle size and slurry concentration. The effect of these parameters on the erosion behavior of coatings was also evaluated. The slurry erosion tests and SEM of the eroded surfaces revealed remarkable improvement in slurry erosion resistance of Ni-15Al₂O₃-5TiO₂ coating in comparison with Ni-20Al₂O₃ coating.

Two different compositions of HVFS coating were developed onto CA6NM steel. Subsequently, these coatings were evaluated by means of mechanical and microstructural characterization. Further, slurry erosion testing was done to analyze the erosive wear behavior of developed coatings.

The coatings were successfully developed by HVFS process. Cross-sectional microscopic analysis of sprayed coatings revealed a continuous and defect-free contact between substrate and coating. Ni-15Al₂O₃-5TiO₂ coating showed higher value of bond strength in comparison with Ni-20Al₂O₃ coating. Under all the testing conditions, Ni-15Al₂O₃-5TiO₂ coatings showed higher resistance to slurry erosion in comparison with Ni-20Al₂O₃ coatings. Rotational speed, average particle size of erodent and slurry concentration were found to have proportional effect on specific mass loss of coatings. The mixed behavior (brittle as well as ductile) of the material removal mechanism was observed for the coatings.

From the literature review, it was found that researchers have documented the various studies on Ni-Al₂O₃, Ni-TiO₂ and Al₂O₃-TiO₂ coatings. No one has ascertained the synergetic effect of Alumina and Titania on the slurry erosion performance of Nickel-based coating. In view of this, the authors have developed Ni-Al₂O₃ and Ni-Al₂O₃-TiO₂ coatings, and an attempt has been made to compare their mechanical, microstructural and slurry erosion characteristics.

This paper aims to depict the erosion performance of two HVOF-coated micron layers (Colmonoy-88 and Stellite-6) on pump impeller steel (SS-410) by using Taguchi's method. Taguchi's array (L16) was used to optimize the erosion wear (in terms of weight loss) by using four influencing parameters such as rotational speed, solid concentration, average particle size and time which were varied at four different levels.

The experiments were carried out by using a Ducom slurry tester with rotational speed in the range of 750-1,500 rpm, solid concentration of 35-65 per cent by weight, time period of 75-210 min and average particle sizes in the range of < 53 to 250 µm. Bottom Ash with a nominal size range of < 53 to 250 µm was used as erodent. The process parameters were optimized by using Taguchi's method. The ANOVA method was used to validate the results given by Taguchi's method.

The results revealed that the presence of both carbides and borides and the additional presence of Cr in Colmonoy-88 coating enhancing the slurry erosion resistance of Colmonoy-88 coating. Moreover, the chromium and tungsten carbide particles help in increasing the bond strength between the coating and the substrate material. Further, it was also found that the time was the most dominant factor as compared to other factors.

The very less work has been reported on optimization of erosion wear response of Colmonoy-88 and Stellite-6 coatings by using different design of experiment techniques. Further, the erosion wear mechanism of both coatings has been studied by using image j analysis software.

This paper aims to optimize the erosion wear analysis of slurry impeller material. Stainless steel (SS-410) was used as the pump impeller material. This erosion test was established to influence the rotational speed, solid concentration, time period and particle size. Fly ash was used as the erodent material.

The erosion wear experiments were performed at different particle size, rotational speed, time duration and solid concentration (by weight). These tests were performed at four different speeds of 750, 1,000, 1,250 and 1,500 rpm, and the time durations of these experiments are 75, 120,165 and 210 min. For protective coating, high-velocity oxygen-fuel spray process was used for depositing WC-10Co-4Cr coating on stainless steel. To investigate the influence of controlled process parameters on slurry erosion wear of pump impeller material, Taguchi method was used.

Results show that significant improvement in erosion wear resistance has been observed by using WC-10Co-4Cr coating. The process parameters affecting the erosion wear loss were in following order: time > rpm > concentration > particle size. The means of signal-to-noise ratio of stainless steel SS410 with and without coating vary from 93.56 to 54.02 and from 86.02 to 48.18, respectively.

For the erosion wear rate of both uncoated and coated stainless steel, the most powerful influencing factor was identified as time. The erosion test reveals that the coating exhibits ductile erosion mechanism and shows better erosion wear resistance (approximately two times) compared to uncoated stainless steel.

This paper aims to evaluate the mechanical properties and slurry erosion behaviour of 10TiO2-Cr2O3 coated turbine steel.

Slurry erosion experiments were performed on the coated turbine steel specimens using slurry erosion test rig under accelerated conditions such as rotational speed, average particle size and slurry concentration. Surface roughness tester, Vickers microhardness tester and scanning electron microscope were used to analyse erosion mechanism.

Under all experimental conditions, 10TiO2-Cr2O3 coated steel showed better slurry erosion resistance in comparison with Al2O3 coated and uncoated steel specimens. Each experimental condition indicated a significant effect on the erosion rate of both coatings and uncoated steel. The surface analysis of uncoated eroded specimen revealed that plastic deformation, ploughing and deep craters formation were the reasons for mass loss, whereas microchipping, ploughing and microcutting were the reasons for mass loss of coated specimens.

The present investigation provides novel insight into the comparative slurry erosion performance of high velocity oxy fuel deposited 10TiO2-Cr2O3 and Cr2O3 coatings under various environmental conditions. To form modified powder, 10 Wt.% TiO2 was added to 90 Wt.% Cr2O3.

This paper aims to perform the solid particle erosion studies in simulated coal-fired boiler conditions with a view to compare the erosion behavior of two different types of detonation gun (D-Gun) sprayed cermet coating powders, that is, WC-12%Co and Cr₃C₂-25%NiCr on ASTM A36 steel and bare (uncoated) ASTM A36 steel.

Erosion studies were performed using an air jet erosion test rig at impingement angles of 45°, 60° and 90°. During the erosion studies weight loss, erosion rates in terms of volume loss (mm³/g) and measurement of erosion profiles were determined using optical profilometer.

Both cermet coatings had successfully protected the ASTM A36 steel from erosion at impingement angles of 45°, 60° and 90°. In the case of bare ASTM A36 steel, the erosion rates were maximal at an impingement angle of 45° and minimal at an impingement angle of 90°, thus depicting the peculiar erosion behavior of ductile materials. WC-12%Co coated specimens exhibited erosion behavior that is closer to the behavior of ductile materials. Cr₃C₂-25%NiCr coated specimens exhibited the maximum erosion rate at an impingement angle of 90° and minimum at an impingement angle of 45°, hence depicting the typical behavior of brittle materials.

It is expected that these results will contribute to the improvement of erosion resistance of induced draft fans, by the application of D-Gun sprayed WC-12%Co and Cr₃C₂-25%NiCr cermet coatings.

This paper evaluates the solid particle erosion behavior of bare and cermet-coated ASTM A36 steel which will be helpful in choosing the suitable cermet coating for induced draft fan applications.