Lakhasly

Experimental 1.Smaller particles, penetrate surface irregularities more effectively.The combined influence of rGO and the Ag/Mo-doped TiO2 catalyst creates a robust coating.Collaboration between these components likely leads to the observed adhesion improvement.These catalyst particles, along with ceria and rGO, create a robust coating.(Kumar, S. (2021, 151, )

Table (1) Composite Coating Composition Percentages

Characterization Field Emission Scanning Electron Microscope Using an Inspect (F 50 FEI company) FESEM microscope to examine the morphology and grain size of the catalyst along with energy dispersive spectroscopy (EDS) Coating Tests 3.6.1 Roughness Measurement The surface degree of roughness of steel specimens was measured after sand blasting using the SRT-6200S Digital Surface Roughness Tester, Meter Gauge, and MERTI MI .They were brought in the form of powder and previously synthesized Ag-Mo/TiO2.Thirty steel plate substrates of specification, ASTM A 516Gr.70 , were cut by (5X5X0.3) cm and shot blasted according to SSPC SP 10 for enhancing the steel surface roughness and establishing favorable circumstances for coating adhesion.After consolidating PVA with Ag/Mo-doped TiO2powder and 0.2-1% ceria (CeO), the coating layer increased to (83-95) microns.1 Mo 0.6 0.1 4.7 0.

Experimental

1. Composite Coating Materials
   Nanocerium oxide, graphene oxide and were supplied by PLATONIC NANOTECH, India, with an average size and properties described in table , as well as polyvinyl alcohol. They were brought in the form of powder and previously synthesized Ag-Mo/TiO2.Thirty steel plate substrates of specification, ASTM A 516Gr.70 , were cut by (5X5X0.3) cm and shot blasted according to SSPC SP 10 for enhancing the steel surface roughness and establishing favorable circumstances for coating adhesion. The process mechanism involves spraying sand onto the surface with a sandblasting device. The sandblasting machine has two main parts: the blast pan and the air intake. The cleaning pan holds the abrasive blasting agent and directs the particles through the valve. The inlet is provided by an air compressor that pressurizes it in the chamber, then passes through a nozzle at high speed and hits the surface with impact. Sand particles range from 10-20 microns and pressure 100 MPa. Mill scale, rust, and debris have all been removed to produce a clean exterior for subsequent coating. Specimens were cleaned by acetone to prevent further oxidation. (Wang, H., (2019)., 245, 1-10.)

Figure (1)
Preparation of Composite Coating
Firstly, sample the PVA was oxidized by adding 10 ml of H2O2 to 100 ml of DW and 10 gm of PVA with stirring at 60 ℃ for 2 hours then dried and collected. Poly vinyl Alcohol was mixed thoroughly with Ag/Mo doped TiO2 in quantities as described in table below and were tested for desulfurization. The next step involved reducing graphene oxide using a 99% hydrazine solution. A ratio of 1 ml to 100 mg hydrazine to graphene oxide and 100 ml of DW were stirred with heating at 100 for 2 hours and left to age for a day, followed by drying at 120 for two hours in the drier. Following the preparation of all materials, blending Ag/Mo-doped TiO2 powder, oxidized PVA, rGO, and nanoceria in significant amounts using 100 ml of ethanol and DW, agitated for three hours, and aged the mixture overnight. The mixture was a homogenous suspension that could be easily applied by spraying the steel specimen surface. Then the coated surface allowed to cure and then heat treated for 4 hours at 180c. (Kumar, S. (2021, 151, )

Table (1) Composite Coating Composition Percentages

Characterization
Field Emission Scanning Electron Microscope
Using an Inspect (F 50 FEI company) FESEM microscope to examine the morphology and grain size of the catalyst along with energy dispersive spectroscopy (EDS)
Coating Tests
3.6.1 Roughness Measurement
The surface degree of roughness of steel specimens was measured after sand blasting using the SRT-6200S Digital Surface Roughness Tester, Meter Gauge, and MERTI MI . The procedure was carried out in accordance with ASTM D7127.
Coating Mechanical Tests
The selected PV-Composite coatings were testing for better performance as follow:
Coating thickness
In accordance with ASTM D7091 , College of Engineering, Materials Engineering Lab, applied coating films were measured by an ultrasonic POSITECTOR 6000 UK device.
Microhardness
PosiTector SHD, SHOR D, UK, was used to measure the microhardness of coated layers. The indentation and measurement comply with the standard ASTM D2240 .

Adhesion Test
Using PosiTEST (AAT-M, UK-made), a dolly-type adhesion tester was used to estimate the contact force between steel specimens and coating according to ASTM D4541 .( Li, Y., (2018). 735, 1234-1242).
Discussion
Coating Results
Materials Characterization
The FESEM image of the PVA + Ag/Mo-TiO2powder discloses its surface morphology. Searching for characteristics, irregularities, and any discernible structure is crucial. PVA naturally exhibits a porous structure, characterized by interconnected voids. The image also provides insight into the size of catalyst particles dispersed within the PVA matrix.
The visible agglomeration and obvious contrast clearly indicate the function groups. The addition of rGo, as evidenced by the composites' pictures, suggests a potential mechanism for the Ag-MO TiO2/PVA nanocomposite. The medium's primary formation of the composite and rGo was uniformly discrete, owing to the fine grain size and flaky shape of the rGO sheets in the micrograph.
Ceriaaddition increased roughness irregularity and the distribution wasn’t uniform because it aggregated in larger particle size. With combining all coating constituents, increasing ceria amounts augmented coating surface roughness but not the rGO or Ag/Mo doped TiO2where they both indicate fine grain size and good distribution.FESEM images revealed in fig (). Heat treatment at 180℃ evidently reduces the nano cracks in the consistency as in figs ()which will enhance the photocatalytic activity. Also boosted the exposure of catalyst to specimen surface

Figure (2 ) Ag/MO / TiO2 PVA Coating

Figure (3) Ag/MO TiO2/PVA ,rGO

Figure (4) Ag/MO/ TiO2PVA ,Ceria

Figure (5)Ag/Mo TiO2 Coating Ceria +rGO

Figure (6) FESEM Micrograph of Coating Surface a before heat treatment

b-after heat treatment
Figure(7) Coating Surface before and after Heat Treatment
EDS
The coating elements are dispensed in significant amounts within thecoating interiors in Fig. and Table . Due to the presence of rGO and PVA, carbon and oxygen are the predominant elements in the coating. An exceptional percentage of oxygen indicates the association between rGO and TiO2. Silver has a higher quantity than molybdenum, which achieves effective doping as a catalyst. Iron appeared as part of the analysis, which could be the result of some surface exposure or the beam arrays reaching to some specimen edges, but still a very small quantity of overall elements. The data display is aided by the mapping of all components.

Figure (8) EDS Mapping for Composite Coating

Table (2) Elements Analysis By EDS For Composite Coating
ELEMENT ATOMIC % ATOMIC % ERROR WEIGHT % WEIGHT % ERROR
C 43.5 0.39 29.6 0 .2
O 50.0 0.6 45.4 0.6
Ti 3.6 0 9.7 0.1
Fe 0.5 0 1.7 0. 1
Mo 0.6 0.1 4.7 0. 1
Ag 1.8 0.0 8.9 0.7

Fig () and table( ) expose the elemental dissemination with addition of Ceria.

Figure (9) EDS Mapping for Composite Coating with CeO2

Table(3) Elements Analysis By EDS For Composite Coating with CeO2
ELEMENT ATOMIC % ATOMIC % ERROR WEIGHT % WEIGHT % ERROR
C 43.9 0.4 24.0 0.2
O 47.4 0.7 34.6 0.5
Ti 5.2 0.0 26.8 0.1
Fe 0.2 0.0 0.1 0.1
Mo 0.7 0.2 4.2 0.8
Ag 1.7 0.0 7.3 0.1
Ce 1.1 0.0 7.4 0.3

Because of CeO2chemistry, the oxygen level was higher. Carbon and titanium are still the predominant elements after oxygen. Cerium is incorporated into the coating materials in smaller quantities than titanium. The coating materials also contain silver and molybdenum in the same amounts as dopants. Mapping illustrates the dispersal thoroughly.

Coating Thickness
The thickness of coating layers varied with different types and amounts of modules. With a spectrum of PVA accumulation (1-4%) of total Ag/Mo-doped TiO2powder weight, the coatings' readings slightly diverged between 64-70 micrometers. The difference of a few microns was attributed to an increase in PVA percentage. The catalyst particle size embedded within the coating majorly influences the thickness. The obtained catalyst nanosize (32 nm) determines how densely the particles are packed in the coating . Nano-sized particles can be closely packed, resulting in a thicker coating. Large surface areas, as examined by AFM, also played a key role in coating surface coverage and diffused homogenously .
If the total formulation remains constant, the coating thickness didn’t change significantly (72 microns) for all rGO propotions. However, the nanosized rGO sheets dissolve consistently and don’t agglomerate. Suitably dispersed rGO can cover defects and improve surface regularity .
After consolidating PVA with Ag/Mo-doped TiO2powder and 0.2-1% ceria (CeO), the coating layer increased to (83-95) microns. Clusters of Ceria Bits formed large agglomerates, and the addition boosted the total solid content in the mixture. Higher particle loading leads to a thicker layer due to increased material deposition . Ceriaalso praised surface roughness for dispersing non-uneven particles.
The synergistic effect of mixing different ratios of Ag/Mo-doped TiO2with 4% (ceria, rGO, and PVA) significantly increased coating thickness to approximately 120 microns. These catalyst particles possibly contribute to the overall thickness due to their diffusion within the coating ground. Fig. illustrates the relationship between catalyst particle size and coat thickness.

Figure (10) Effect of Coating Elements on Layer Thickness
Microhardness
PVA is commonly used as a binder in coatings, films, and composites. This polymeric material is comparatively soft related to materials like metals or ceramics. Because PVA isn’t the dominant in the composite coating, the behavior will depend on catalysts properties. The microhardness of Ag/Mo-doped TiO₂ was 95.5 which means the smaller particle size (32 nm) particles[] aided to the hardness due to their nano particle size and intemperance within the coating matrix[].
With adding rGO the microhardness only enhanced by one micron to be 95.6. this attributed to the very fine graphene oxide flakes which can diffuse evenly providing good coverage but not for microhardness .
By means of Ceria, the microhadness reached 96 shore D. It further enhance cross linking and hardness. Synergetic effects of Ag/Mo-doped TiO₂ and ceria contributed to the overall harness . Big ceria agglomerates supported particle stacking and dispersion play a role.

Including all composite coating elements (Ag/Mo doped TiO2+ rGO + Ceria) with 0.04 gm of PVA converting it to a coat, the microhardness didn’t change remain 96 shore D. Ceria, rGO, and Ag/Mo-doped TiO₂ together didn’t improve the microhardness than catalyst with Ceria only because rGO didn’t back the microhardness much. Curing conditions remain criticalbut since constant for all coating conditions it will be neglected. Fig()displays the microhardness values for coating samples.

Figure(11) Microhardness for Coating Types
Adhesion and related Surface Roughness
Steel specimen surface designated at 0.03 microns roughness comply to the SA
2.5 . A rougher Steel Surface provides more mechanical interlocking sites
2 60 The adhesion forces of coatings to the steel specimen were calculated by
pull off test , and results are concise in fig . The pull off test for
PVA/ Ag/Mo doped TiO ₂ measured an adhesion strength of 10.23 MPa. Smaller
nano particle size tend to develop adhesion The 32 nm, the Ag/Mo doped TiO ₂
particles likely contribute to good bonding with the substrate. Smaller particles can penetrate and anchor to surface irregularities and create strong interfacial. The combination of roughness and particle size donates to the strong adhesion. On the other hand, larger surface area811nm2provides more contact points for adhesion. The high surface area of the Ag/Mo-doped TiO₂ particles promotes effective bonding. It allows for better coverage and interaction with the steel surface .
For rGO addition ,the adhesion increased to 13.67 Mpa.Well-dispersed, rGO forms bridges between the coating and the steel substrate that enhanced Adhesion.The combination of rGO’s mechanical properties and its interaction with the steel surface likely contributes to the increased adhesion.
Smaller particles, penetrate surface irregularities more effectively.The combined influence of rGO and the Ag/Mo-doped TiO₂ catalyst creates a robust coating.Collaboration between these components likely leads to the observed adhesion improvement.
When Ceriaintroduced to the matrix of Ag/Mo doped TiO2, the adhesion elevated to 16.82 Mpa. Ceria’sredox behavior enhances metal-support interactions.The strong interaction between ceria and the steel substrate likely contributes to the increased adhesion.The combined effect of Ag/Mo-doped TiO₂ and ceria creates a robust coating[]. Adhesion strength suggests successful bonding and improved coating performance.The remarkable increase in adhesion strength to 22.33 MPa after adding ceria, rGO, Ag/Mo-doped TiO₂, and PVA. These catalyst particles, along with ceria and rGO, create a robust coating. Collaboration between the components leads to the observed high adhesion strength.