Journal of Thermal Spray and Engineering, 4: 154-161

ISSN (Online): 2582-1474; DOI: https://doi.org/10.52687/2582-1474/411

Peer-Reviewed ATSC2023 Special Issue

Slurry Erosion Behaviour of HVOF Sprayed WC-10Ni-5Cr Coated

35CrMo Steel
Pradeep Raj R. · D. Thirumalaikumarasamy

Annamalai University, Chidambaram Tamil Nadu – 608002, India.

ARTICLE HISTORY
ABSTRACT Received 13-07-2024
Slurry erosion is a serious operational difficulty that results in severe equipment damage, downtime, and Revised 28-08-2024
material replacement costs. To address this issue, the High Velocity Oxy Fuel (HVOF) spraying process is Accepted 07-09-2024
utilised to impart protective ceramic coatings to steel substrates, increasing their resistance to slurry Published 23-09-2024
erosion. In this investigation slurry erosion studies were carried out, with parameters such as rotating
speed, impingement angle, slurry concentration, and exposure period being varied to understand their KEYWORDS
impact on erosion behaviour. Developed empirical correlations that accurately forecast coating mass loss WC-10 Ni-5Cr coatings
using response surface methodology (RSM). A five-level central composite design matrix is used to optimize High Velocity Oxy Fuel
the experimental runs, resulting in a model with more than a 95% confidence level. Findings highlight the Response Surface
dominant influence of exposure time, followed by rotational speed, impact angle, and slurry concentrations Methodology
on coating erosion rates. Slurry erosion
©The Indian Thermal Spray Association, INSCIENCEIN. 2024.All rights reserved

Introduction turbines. Slurry erosion can remove protective coatings

Slurry erosion is a type of material degradation caused by and expose underlying materials to the corrosive marine
the impact of solid particles suspended in a fluid (usually a environment, leading to accelerated corrosion rates. The
liquid) on a surface. This phenomenon is particularly effect of slurry erosion on naval materials depends on
relevant in various industrial applications where materials several factors, including the composition of the material,
are exposed to abrasive environments. Slurry erosion can the properties of the slurry, the impact velocity, and the
result in the gradual removal of material from the surface angle of impact. To mitigate the effects of slurry erosion on
of components, leading to dimensional changes and loss of materials, various strategies can be employed, including
structural integrity. This can cause parts to become weaker selecting steel alloys with higher hardness and resistance
and less effective at performing their intended functions. In to abrasion, applying protective coatings, altering the flow
industries where fluid-solid mixtures are processed, such conditions to minimize impact velocity, and using designs
as in pipelines, pumps, and valves, slurry erosion can cause that minimize the angle of impingement. Preventing slurry
an increase in friction and turbulence, leading to reduced erosion in steel components using High-Velocity Oxygen
efficiency and increased energy consumption. Slurry Fuel (HVOF) coatings is an effective approach to extend
erosion can accelerate the wear of equipment components, their service life and maintain their performance. High-
leading to premature failure. Components that experience Velocity Oxygen Fuel (HVOF) is a thermal spray process
erosion, such as impellers, rotors, and chutes, may need to where a mixture of fuel gas and oxygen is ignited in a
be replaced more frequently, leading to higher combustion chamber, producing a high-velocity flame.
maintenance and replacement costs. Slurry erosion can Powdered coating material is fed into this flame, melts, and
compromise the structural integrity of equipment, is accelerated onto the substrate to form a dense, adherent
increasing the risk of sudden equipment failure. This can coating. HVOF coatings are known for their exceptional
pose safety hazards to workers, especially in industries wear resistance properties. They can significantly extend
where the failure of certain equipment could lead to the lifespan of components subjected to abrasive wear,
accidents. Eroded particles from equipment can enter the erosion, and friction [7-14].
surrounding environment, leading to potential Several researchers have documented the effectiveness of
contamination of water, soil, and air. This can have traditional coating-like plasma spraying and combustion
negative ecological impacts on local ecosystems [1-7]. In flame process in enhancing resistance to slurry erosion
marine environments, where water and abrasive particles when compared to uncoated base materials, attributing
are prevalent, slurry erosion can lead to various challenges this improvement to their high hardness. The prevailing
and consequences. Slurry erosion can cause accelerated erosion mechanism observed across various experimental
wear and tear on equipment surfaces exposed to the approaches involves the shedding of layers due to crack
abrasive slurry. This includes pipes, valves, pumps, initiation and propagation induced by fatigue stress [15-
propellers, and other components. The erosion of these 16]. Notably, studies have highlighted the substantial
components can lead to reduced operational efficiency, enhancement in wear resistance across cavitation, slurry
increased maintenance needs, and shorter equipment erosion, and dry erosion environments when utilizing high-
lifespans. This might result in decreased propulsion velocity air-fuel sprayed coatings as opposed to bulk
efficiency for ships, reduced pumping capacity for offshore materials [17]. In a study by Men et al. [18], the erosion
platforms, and decreased energy generation for marine process was found to induce thermal shock cracks on the

Corresponding Author: R. Pradeep Raj, Tel: +91 7558009711 ©The Indian Thermal Spray Asso., INSCIENCEIN. 2024
Email: krsreeraj1@gmail.com
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Pradeep Raj R. et al., Slurry Erosion Behaviour of HVOF Sprayed WC-10Ni-5Cr Coated 35CrMo Steel

coating's surface, leading to the fracture and removal of better overall coating quality. The increased packing
surface carbides by the hot airflow, resulting in erosion density and improved flowability of agglomerated and
pits. Furthermore, the addition of Ni phase was observed to sintered powders contribute to better adhesion between
enhance the substrate's erosion resistance. Another the coating and substrate. This results in higher bond
investigation by Sing et al. [19] involved a comparative strength, reduced risk of delamination, and increased
analysis of Ni-Cr-O and NiCrBSiFe-WC (Co) composite overall coating durability. Figure 2 shows the uncoated
coatings, deposited using the HVOF technique, focusing on and coated sample and figure 3 shows the SEM image of
erosion resistance. This improvement was primarily coating cross section.
attributed to the superior hardness of the HVOF-sprayed
coatings in contrast to the bond coating. Tripathi et al. [20] Table 1: Chemical composition of Substrate
conducted a comprehensive study exploring various Percent C% Si% Mn% P% S% Cr% Mo%
coating materials, such as tungsten carbide with traces of comp 0.35 0.2 0.602 0.015 0.012 0.972 0.205
cobalt, nickel, and rare earth elements, and assessed the
Table 2: Chemical composition of coating powder
impact of different coating parameters, including
Percent C% Cr% Ni% Fe% W%
impingement velocity, particle size, and impingement comp 5.4 5.03 10.25 0.06 Balance
angle. Their findings underscored the significant
enhancement of erosion resistance behaviour in stainless- Before the spraying procedure, the base material
steel substrates through the application of cermet coatings. underwent preheating, achieved by subjecting it to a
While extensive research has explored the erosion complete torch cycle at a velocity of 0.8 m/s, resulting in a
behavior of thermal sprayed coatings, the interplay temperature range of 120–180°C. The specimens used in
between substrate material properties and coating this research possessed dimensions of 25 × 25 × 3 mm,
characteristics on erosion resistance remains a subject of featuring chamfered edges with a one-millimetre extension
ongoing investigation. This study aims to contribute to this and a 45° angle. The specimens were cleaned using acetone
understanding by comprehensively examining the slurry through ultrasonic cleaning. Additionally, the surface
erosion behavior of HVOF-coated 35CrMo steel, a roughness of the base material was enhanced by grit
commonly used material in critical applications. By blasting process using corundum particles (sized between
investigating the synergistic effect of substrate and coating 320- 500 μm).
properties, this research seeks to provide valuable insights A Mitutoyo Surf Test 301 surface roughness tester from
for the design and optimization of erosion-resistant Japan was employed to measure the surface roughness. The
coatings in demanding environments. Here, authors base materials, after undergoing grit blasting, exhibited an
employed the HVOF method to apply a conventional WC-10 average roughness ranging from 5μm to 10μm.The
Ni 5 Cr feed powder onto a 35CrMo steel surface. 35CrMo conventional powder mixture used in the process consisted
alloy steel can be used in various applications that of the following weight percentages: 85% tungsten carbide
withstand impact, bending and high loads and in marine (WC), 10% nickel (Ni), and 5% chromium (Cr). The particle
applications and used to manufacture parts such as rolling size of these powders ranged from +15μm to -45μm.The
mill gears, crankshafts, connecting rods, fasteners, process parameters for the WC 10Ni 5Cr coating using
automotive engine spindles, axles, engine transmission High-Velocity Oxygen Fuel (HVOF) are presented in Table
parts, propeller shafts, bolts for boilers etc. A 3.
comprehensive slurry erosion experiment was carried out Table 3: HVOF process parameters
to evaluate the performance of the coating under varying
Process parameters Range
conditions like slurry composition, rotational speed, impact
angle, and duration using response surface methodology Oxygen flow rate 252.5 slpm
(RSM). RSM is a valuable statistical technique for analysing LPG flowrate, 55 slpm,
slurry erosion behavior in HVOF-coated 35CrMo steel. Its Powder feed rate 45 g/min
ability to efficiently design experiments, develop models,
Spray distance 6.5 inch
optimize processes, and understand complex interactions
makes it an indispensable technique for researchers and
engineers working in this field.

Experimental
In this study, a WC-10Ni 5Cr powder (Make: Oerlikon
metco WOKA-3552) coating was applied using the HVOF
spray technology (HIPOJET-2700) provided by Aum
Surface Technology, Bangalore, India. The coating was
applied onto a 35CrMo steel surface, with a resultant
thickness of approximately 250 μm. The chemical
composition of both base material and coating powder is
shown in table no.1 & 2. The coating thickness was
determined using a digital micrometre with a precision of
0.001 mm, varying based on the number of passes during
the coating process. Figure 1 shows the SEM image of
coating powder. It confirms the nature of the powder
particle as agglomerated and sintered with spheroidal
morphology. This ensures the consistent particle sizes and
shapes. This leads to improved powder flowability, reduced Figure 1: SEM micrograph of WC 10 Ni 5 Cr powder
porosity, and enhanced coating consistency, resulting in

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Pradeep Raj R. et al., Slurry Erosion Behaviour of HVOF Sprayed WC-10Ni-5Cr Coated 35CrMo Steel

Figure 2: (a) Uncoated Steel (b) Coated steel

Figure 3: SEM micrograph of coating (Cross section)

Figure 4: Coated samples(a) before and (b) after slurry erosion

testing

Slurry erosions analysis Figure 5: (a) Slurry Erosion Tester (b) Schematic arrangement
Samples of 35 Cr Mo steel with dimensions 25 mm x 25 mm of slurry erosion testing
x 5 mm were subjected to slurry erosion testing as per
ASTM G 73 standards in a slurry erosion tester (Make: The study considers several key factors, including
DUCOM Instruments, India, Model: TR-40). Figure 4 shows rotational speed, impinging angle, slurry concentrations,
the samples before and after the testing. Prior to the and time, which have been identified as significant
commencement of the experiment, the samples underwent determinants based on prior research [21-30]. Initial trial
ultrasonic cleaning and were meticulously washed using tests were conducted to establish operational ranges for
precise weighing equipment. These samples, which were the variables impacting slurry erosion. Conducting erosive
uniform in size, were securely fastened to a disc at the wear tests is feasible once the applicable ranges for erosion
desired radial distance. The disc, together with the sample, test instrument capabilities have been accounted for within
was fully immersed in the slurry. Upon initiating the motor, the erosion conditions. To streamline the analysis process,
the samples were set into rotation for a predetermined statically generated experiments were employed to assess
duration at the desired speed. Upon completion of the the impact of varying slurry erosion parameter values on
experiment, the specimen was extracted and subjected to a mass loss. The investigation encompasses both the 35CrMo
thorough washing process. The evaluation of mass loss, steel aspects, outlined in Tables 4 and 5. To minimize
influenced by various experimental conditions, was methodological errors, the tests were performed in a
employed to calculate the rate of mass loss. For the slurry random sequence. Reliability assessment involved
erosion investigations, an erodent consisting of 50 μm conducting three tests for each experimental condition to
quartz sand was employed. Figure 5 showing the slurry ensure consistent results.
erosion tester and its schematic arrangement.

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Pradeep Raj R. et al., Slurry Erosion Behaviour of HVOF Sprayed WC-10Ni-5Cr Coated 35CrMo Steel

Table 4: The experiment parameters and levels

No Factor Units Notation Levels
-2 -1 0 1 2
1 Impact angle degree A 30 45 60 75 90
2 Rotational rpm S 500 750 1000 1250 1500
Speed
3 Time min T 30 60 90 120 150
4 Slurry g/cc F 200 300 400 500 600
Composition

Table 5: The design matrix and measured responses

Exp. Time Rotational Impact Slurry Mass Mass
condition (min) speed angle composition loss of loss of
(rpm) (Degree) (g/cc) uncoated coated
steel (g) steel(g)
1 60 750 45 300 0.06 0.0402
2 120 750 45 300 0.1563 0.1037
3 60 1250 45 300 0.1161 0.0771
4 120 1250 45 300 0.2107 0.1394
5 60 750 75 300 0.1067 0.0709
6 120 750 75 300 0.2034 0.1346
7 60 1250 75 300 0.1582 0.105
8 120 1250 75 300 0.2532 0.1674
9 60 750 45 500 0.041 0.0277
10 120 750 45 500 0.1401 0.093
11 60 1250 45 500 0.0893 0.0596
12 120 1250 45 500 0.1867 0.1236
13 60 750 75 500 0.0829 0.0554
14 120 750 75 500 0.1824 0.1208
15 60 1250 75 500 0.1266 0.0844
16 120 1250 75 500 0.2244 0.1485
17 30 1000 60 400 0.0513 0.0346
18 150 1000 60 400 0.2454 0.1623
19 90 500 60 400 0.0975 0.0649
20 90 1500 60 400 0.1956 0.1296
21 90 1000 30 400 0.1061 0.0705
22 90 1000 90 400 0.1905 0.1262
23 90 1000 60 200 0.1652 0.1095
24 90 1000 60 600 0.1174 0.0781
25 90 1000 60 400 0.1416 0.0939
26 90 1000 60 400 0.06 0.0402
27 90 1000 60 400 0.1563 0.1037
28 90 1000 60 400 0.1161 0.0771
29 90 1000 60 400 0.2107 0.1394
30 90 1000 60 400 0.1067 0.0709

Predictive statistic model for erosion rate – 0.0008 (A)(F) +-0.0027 (T2) + 0.0024 (S2) + 0.0027 (A2)
In this work, mass loss was determined in relation to +0.0016 (F2) …………. (3)
rotation speed, impact angle, slurry concentration, and
time using a response surface technique. An experimental
quadratic correlation was constructed to determine the Results and Discussion
response by experiment values in order to compare the In this work, the appropriate empirical relationship was
experimental components with the rates of erosion [31] . confirmed using the ANOVA methodology. Tables 6 and 7
Output (Responses) = f (T, S, A, and F) can be used to shows the ANOVA findings for the degree of erosion in both
indicate the responses based on impacting angle (A), coated and uncoated samples. The process for analysing
rotational speed (S), time (T), and slurry concentration (F) the ANOVA data is laid out in the literature [32]. The
The finalized experimental relation for assessing the output analysis presented in Tables 6 and 7 indicates that erosion
is rate is significantly influenced by rotation speeds,
impingement angles, duration, and slurry concentration –
Mass loss of uncoating 35CrMo steel base material = 0.1319 as evidenced by their substantial impact values ('F' value
+ 0.0485 (T) + 0.0245(S) + 0.0211 (A) – 0.0119 (D) – 0.0004 assessment). These findings underscore the robustness of
(T)(S) + 0.0001 (T)(A) + 0.0007 (T)(F) – 0.0012 (S) (A) – the regression models in accurately capturing these
0.0020 (S)(F) – 0.0012 (A) (F) + 0.0041 (T2) + 0.0037 (S2) + relationships. By manipulating the coded representations
0.0211 (A2) – 0.0024 (F2) ……… (2) of experimental factors, these empirically derived
relationships could effectively serve as predictive tools for
Mass loss of WC- 10Ni 5Cr coatings = 0.0875 + 0.0319(T) + anticipating outcomes.
0.0162 (S) – 0.0139 (A) – 0.0078 (F) +0.0003 (T) (S) +
0.0001(T)(A) + 0.0004 (T)(F) – 0.0007 (S)(A) – 0.0013 (S)(F)

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Pradeep Raj R. et al., Slurry Erosion Behaviour of HVOF Sprayed WC-10Ni-5Cr Coated 35CrMo Steel

Table 6: ANOVA analysis for erosion rate of uncoated 35CrMo steel substrate
Source Sum of df Mean F-value p-value
Squares Square
Model 0.0862 14 0.0062 7.13 0.0003 significant
T-Time 0.0565 1 0.0565 65.44 < 0.0001
S-Rotational 0.0144 1 0.0144 16.72 0.001
Speed
A-Impact Angle 0.0107 1 0.0107 12.37 0.0031
F-Slurry 0.0034 1 0.0034 3.97 0.0649
Composition
TS 2.89E-06 1 2.89E-06 0.0033 0.9546
TA 1.60E-07 1 1.60E-07 0.0002 0.9893
TF 7.84E-06 1 7.84E-06 0.0091 0.9254
SA 0 1 0 0.0245 0.8777
SF 0.0001 1 0.0001 0.0705 0.7943
AF 0 1 0 0.0267 0.8724
T² 0.0005 1 0.0005 0.5372 0.4749
S² 0.0004 1 0.0004 0.4261 0.5238
A² 0.0005 1 0.0005 0.5339 0.4762
F² 0.0002 1 0.0002 0.1754 0.6813
Residual 0.013 15 0.0009
Lack of Fit 0 10 0 0 1 not significant
Pure Error 0.013 5 0.0026
Cor Total 0.0992 29

Table 7: ANOVA analysis for erosion rate of coated 35CrMo steel substrate

Source Sum of df Mean F-value p-value

Squares Square
Model 0.0374 14 0.0027 7.12 0.0003 significant
A-Time 0.0245 1 0.0245 65.29 < 0.0001
B-Rotational Speed 0.0063 1 0.0063 16.76 0.001
C-Impact Angle 0.0047 1 0.0047 12.42 0.0031
D-Slurry Composition 0.0015 1 0.0015 3.94 0.0659
AB 1.63E-06 1 1.63E-06 0.0043 0.9483
AC 1.56E-08 1 1.56E-08 0 0.9949
AD 2.98E-06 1 2.98E-06 0.0079 0.9302
BC 8.27E-06 1 8.27E-06 0.0221 0.8839
BD 0 1 0 0.0688 0.7967
CD 9.46E-06 1 9.46E-06 0.0252 0.8759
A² 0.0002 1 0.0002 0.5451 0.4717
B² 0.0002 1 0.0002 0.4318 0.5211
C² 0.0002 1 0.0002 0.5351 0.4757
D² 0.0001 1 0.0001 0.1795 0.6778
Residual 0.0056 15 0.0004
Lack of Fit 5.83E-09 10 5.83E-10 5.19E-07 1 not significant
Pure Error 0.0056 5 0.0011
Cor Total 0.043 29

Investigating the slurry erosion parameters of high velocity erosion rate in the coated samples. These results are
oxygen fuel WC-10Ni-5Cr coatings involves a multifaceted evidence for the aptness of WC-10Ni-5Cr HVOF coating for
approach to enhance the coating's resilience against the 35CrMo steel in naval applications. The mass loss of the
abrasive forces encountered in slurry environments. The coating shows minimum values when the rotational speed
goal of the optimisation is to reduce the mass loss (g) due and exposure time are at minimum. At the same time, a
to slurry erosion in 35CrMo steel (coated and uncoated). larger exposure time and rotational speed appear to be the
For this, regression-based model analysis is used to maximum values. This is due to the fact that abrasive
optimise the slurry erosion parameters. Figure 6 and 7 particles have more time to impact and remove material
presents 3D response surface graphs for mass loss (g) in from the coated surface. Erosion might not occur at a
uncoated and coated steel. According to the findings, constant rate throughout time. Erosion may rise quickly at
samples that were coated and uncoated and exposed to 45° first, but it may then stabilise at a stable state as a result of
impingement angle, 500 g/cc slurry concentration, and 60 things like wear debris saturation of the coating surface
minutes of immersion showed minimum mass loss of 0.041 and the development of shielding surface layers. More
g and 0.0277 g. When coated with WC-10Ni-5Cr powder material is removed from the coated surface as a result of
using HVOF, the erosion of 35CrMo steel samples is more frequent and strong abrasive particle collisions
reduced by 32.43%. The 35CrMo steel samples showed a brought on by higher rotational speeds. There can be a
larger mass loss of 0.2532 g and 0.1674 g for both coated speed at which the erosion rate stops increasing noticeably.
and uncoated respectively, when they were exposed After this, increasing rotational speed may not significantly
rotating speed of 1250 rpm, impingement angle of 75°, affect erosion; in fact, it may even have the opposite effect
slurry concentration of 300 g/cc, and immersion duration because of stronger hydrodynamic effects that shield the
of 120 min. This confirms a 51.25% reduction in the surface.

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Pradeep Raj R. et al., Slurry Erosion Behaviour of HVOF Sprayed WC-10Ni-5Cr Coated 35CrMo Steel

Figure 6: 3D response surface graphs for uncoated 35CrMo steel

Figure 7: 3D response surface graphs for coated 35CrMo steel

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Pradeep Raj R. et al., Slurry Erosion Behaviour of HVOF Sprayed WC-10Ni-5Cr Coated 35CrMo Steel

This coating, composed of tungsten carbide (WC) particles elevation, as no single characteristic could explain it. Plastic
embedded in a nickel-chromium (Ni-Cr) matrix, exhibits flows and fractures frequently occur simultaneously when
distinctive characteristics under slurry erosion conditions. hard particles are used in thermal spray coating
The dynamic interplay of factors such as impact angle, degradation [35]. It has been determined that elastic
slurry concentration, rotational speed, and exposure time modules are not suitable for estimating the wear of thermal
influences the overall erosion performance of these spray coats when anticipating the wear of brittle materials,
coatings. Investigation revealed that the erosive wear of nor are they sufficient for industrial ceramics. In this
WC-10Ni-5Cr coatings is influenced by the duration of examination of the erosion performance of thermal spray
exposure, with longer periods contributing to increased technique to their microstructure properties, the most
material removal due to a higher number of impact cycles. significant interrelations were determined to be the
The cumulative effect of even minor impacts becomes hardness, range of porosity, and erosion level of the
evident over time, showcasing the coating's response to material.
prolonged exposure. Moreover, the initial surface damage
acts as nucleation sites for further material removal,
accelerating the propagation of damage with continued Conclusions
exposure. The erosion resistance of materials is the most important
tribological variable that influences their performance in
Slurry erosion behaviour of the HVOF spray WC-10Ni- various industrial applications like marine industries. One
5Cr coatings of most cost-effective means of addressing the issues is to
The slurry erosion behavior of High-Velocity Oxygen Fuel develop HVOF sprayed WC-10 Ni 5Cr coatings with
(HVOF) spray WC-10Ni-5Cr coatings is a subject of superior erosion corrosion resistance. The following are
significant interest and investigation. This coating, some of the most important findings from the study.
composed of tungsten carbide (WC) particles embedded in 1. Empirical relations were established using response
a nickel-chromium (Ni-Cr) matrix, exhibits distinctive surface methodology to predict the slurry erosion
characteristics under slurry erosion conditions. The rate of uncoated and coated specimens of 35 Cr Mo
dynamic interplay of factors such as impact angle, slurry Steel
concentration, rotational speed, and exposure time 2. Among the four factors that observed, the most
influences the overall erosion performance of these predominant factor impacting erosion rate was
coatings. Studies have revealed that the erosive wear of exposure time followed by rotational speed, impact
WC-10Ni-5Cr coatings is influenced by the duration of angle, slurry concentrations.
exposure, with longer periods contributing to increased 3. The HVOF sprayed WC-10 Ni 5 Cr deposit on
material removal due to a higher number of impact cycles outperformed the uncoated substrate in terms of
[33]. The cumulative effect of even minor impacts becomes erosion resistance. Compared to the WC-10 Ni 5 Cr
evident over time, showcasing the coating's response to coated 35CrMo steel, uncoated steel experiences
prolonged exposure. Moreover, the initial surface damage greater mass loss at higher exposure time and
acts as nucleation sites for further material removal, rotational speeds.
accelerating the propagation of damage with continued 4. The 35CrMo steel samples showed a larger mass loss
exposure. of 0.2532 g and 0.1674 g for both coated and
In addition to exposure time, other variables such as uncoated respectively, when they were exposed
impact angle and slurry concentration play crucial roles in rotating speed of 1250 rpm, impingement angle of
shaping the slurry erosion behavior of these coatings. 75°, slurry concentration of 300 g/cc, and immersion
Higher slurry concentrations and more severe impact duration of 120 min.
angles can intensify the erosive effects, leading to enhanced 5. The results confirm a 51.25% reduction in the
material removal. Furthermore, the microstructure of WC- erosion rate in the coated samples and support the
10Ni-5Cr coatings undergoes alterations during slurry suitability of WC-10Ni-5Cr HVOF coating for
erosion, including deformation, strain hardening, and, in enhancing the erosion resistance of 35CrMo steel in
some cases, phase transformations. naval applications.
The primary mechanism of erosion for coatings based on
carbides was attributed to the low hardness of the metal References
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JTSE Vol. 4, 2024, pp 154-161 ©The Indian Thermal Spray Asso., INSCIENCEIN. 2024
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