Enhancement of mechanical and corrosion resistance properties of electrodeposited Ni–P–TiC composite coatings

In the present study, the effect of concentration of titanium carbide (TiC) particles on the structural, mechanical, and electrochemical properties of Ni–P composite coatings was investigated. Various amounts of TiC particles (0, 0.5, 1.0, 1.5, and 2.0 g L−1) were co-electrodeposited in the Ni–P matrix under optimized conditions and then characterized by employing various techniques. The structural analysis of prepared coatings indicates uniform, compact, and nodular structured coatings without any noticeable defects. Vickers microhardness and nanoindentation results demonstrate the increase in the hardness with an increasing amount of TiC particles attaining its terminal value (593HV100) at the concentration of 1.5 g L−1. Further increase in the concentration of TiC particles results in a decrease in hardness, which can be ascribed to their accumulation in the Ni–P matrix. The electrochemical results indicate the improvement in corrosion protection efficiency of coatings with an increasing amount of TiC particles reaching to ~ 92% at 2.0 g L−1, which can be ascribed to a reduction in the active area of the Ni–P matrix by the presence of inactive ceramic particles. The favorable structural, mechanical, and corrosion protection characteristics of Ni–P–TiC composite coatings suggest their potential applications in many industrial applications.


Material and methods
Materials. Nickel sulphate hexahydrate, nickel chloride hexahydrate, boric acid, orthophosphoric acid, and sodium hypophosphite were bought from the Sigma Aldrich, Germany. Sodium chloride and submicron-sized titanium carbide (TiC) powder with an average particle size < 200 nm and purity of 99.9% were also imported from Sigma Aldrich.
Sample preparation and coatings synthesis. The electrodeposition of Ni-P and Ni-P-TiC composite coatings was carried out on the mild steel substrate. Firstly, the mild steel sheet was cut down to the 32 mm square sheets through sheet metal operation. The mild steel samples were then polished to obtain a mirror-like surface with SiC abrasive papers of grit size 120, 220, 320, 500, 800, 1000, and 1200. The substrates were washed with soap and water before moving to the next abrasive paper. After grinding, the substrates were sonicated in the acetone for half an hour. One side of the substrates was covered with insulating tape to avoid electrodeposition on both sides of the substrates. The substrates were activated in 20% HCl solution for about 45 s, rinsed in distilled water, and finally put in the coating bath. During the electrodeposition process, the dc power supply's negative electrode was connected to the substrate forming a cathode, and the positive electrode of the power supply was connected to the nickel sheet to provide an anode. The schematic diagram of the electrodeposition experimental setup is represented in Fig. 1. The nickel sheet (anode) and the substrate (cathode) were placed parallel and face to face each other at a distance of approximately 30 mm in the coating bath. The optimized electrodeposition conditions are tabulated in Table 1. Ni-P and Ni-P-TiC composite coatings were developed at 65 °C ± 2. The time of the coatings is half an hour from the start of the power supply. The coating bath was agitated at 300 ± 5 rpm for 60 min before initiating the electrodeposition process to avoid settling down of the TiC particles. The coating bath was kept agitated during the entire coating process at 300 rpm for uniform distribution of reinforcing particles into the Ni-P matrix.
Sample characterization. The thickness of the synthesized Ni-P and Ni-P-TiC composite coatings was determined by thickness gauge (model BDYSTD-E, USA). Structural characterization of the synthesized coatings was carried out employing X-ray diffractometer (PANalytical, Empyrean, UK) fitted with Cu Kα radiations with the scanning step of 0.02° in the range of 2θ from 10° to 90°. The field emission scanning electron microscope (FE-SEM-Nova Nano-450, Netherlands), atomic force microscopy (AFM-USA) and high-resolution transmission electron microscope (HR-TEM FEI : TECNAI G2 FEG 200 kV) were used to perform the morphological study. The composition of the prepared coatings was also determined by X-ray photoelectron spectroscopy-XPS (Kratos Analytical Ltd, UK) using a monochromatic Al-Kα X-Ray source. The hardness of the prepared coatings was tested with Vickers microhardness tester (FM-ARS9000, USA). The measurement of the www.nature.com/scientificreports/ microhardness was carried out at 100 gf with the dwell time of 10 s on the surface of the coatings. The nanoindentation measurements were performed employing AFM device MFP-3D Asylum research (USA) equipped with silicon probe (Al reflex coated Veeco model-OLTESPA, Olympus; spring constant: 2 Nm −1 , resonant frequency: 70 kHz). All measurements were carried out under ambient conditions using standard topography A.C. air (tapping mode in the air). The indentation was performed with Berkovich diamond indenter tip with a maximum 1mN indentation force (loading and unloading rate: 200 µN/s and dwell time at maximum load: 5 s). Oliver and Pharr's method was used to find contact penetration from the unloading curves. The electrochemical impedance spectroscopy (EIS) studies were carried out with Gamry cell in which saturated silver/silver chloride (Ag/AgCl) was used as the reference electrode, whereas graphite and prepared coated samples were employed as counter and working electrodes, respectively. EIS was measured by AC signal with 10 mV of amplitude within the frequency range of 10 5 -10 −2 Hz at open circuit potential. Moreover, potentiodynamic studies were carried out at ambient room temperature with a scan rate of 0.167 mV s −1 after the determination of open circuit potential for more than 10 min of stabilization of complete cell. A constant surface area of 0.765 cm 2 of all tested samples was exposed to 3.5 wt% NaCl solution in the entire study 33,42,43 . Results and discussion XRD analysis. The structural analysis of the electrodeposited Ni-P and Ni-P-TiC composite coating was carried out through XRD and the spectra of NiP and Ni-P-TiC composite coatings containing various compositions of TiC (0, 0.5, 1.0, 1.5, 2 g L −1 ) are shown in Fig. 2. The semi-amorphous structure of the coatings can be deduced from the broad peaks in all the cases, and the broad peak located at 2Ɵ ~ 45.5 can be assigned to the Ni (111) plane of face-centered cubic (FCC) structure. The formation of an amorphous structure can be ascribed to the lattice distortion experienced by the nickel crystal structure due to the presence of phosphorous atoms, which hinders the propagation of face-centered cubic occupancy of nickel atoms 44 . The amorphous nature of the coatings has already been reported 10,15,45 along with nanocrystalline structure as reported in the literature 46,47 .  www.nature.com/scientificreports/ The diffraction peaks of the TiC were not observed in the XRD spectra, probably due to their low contents in the Ni-P matrix. Similar results have also been reported in the literature 29,48 .

XPS analysis.
The presence of TiC in the Ni-P TiC composite coatings was confirmed using XPS analysis.
To avoid any repetition, the fitted data of individual photoionizations and their corresponding chemical states only the 1.5 g L −1 TiC composition is presented in Fig. 3. High energy resolution spectra of Ni2p (Fig. 3a)    www.nature.com/scientificreports/ and other surface oxidation phenomenon 33,49 . Concerning the P2p ionization, the peaks at 128.8 and 129.5 eV can be assigned to the elemental phosphorous (P) in the bulk of electrodeposited Ni-P-TiC composite coating, respectively (Fig. 3b). It can be noticed that the peak at 130.69 eV is due to (i) elemental phosphorus hypophosphite and/or (ii) intermediate phosphorous ions (P(I) and/or P(III)) valence which are presented in the inner portion of the protective film of the Ni-P coatings. However, peaks at 132.7 eV can be due to the combination of oxides and/or hydroxides (P 2 O 3 and/or P-OH) chemical states 33 . The high-resolution spectra of the Ti2p spectrum were deconvoluted into three doublet peaks (Fig. 3c)  Microstructural analysis. The morphology of the Ni-P and Ni-P/TiC composite coatings containing various concentrations of TiC particles was studied with FE-SEM as specified in Fig. 4. Ni-P coatings ( Fig. 4(a) does not show the formation of a well-defined nodular structure. A similar morphology of Ni-P coatings has been reported in the literature 29,52 . On the other hand, FE-SEM micrographs of Ni-P-TiC composite coatings ( Fig. 4b-e) show the compact, nodular morphology without any noticeable defects. The presence of TiC particles can also be observed in the FE-SEM images, especially at the 2.0 g L −1 of composition in good agreement with literature 33,53 . Figure 4f shows the cross-section of Ni-P-TiC (1.5 g L −1 ) composite coatings. A smooth and well-adherent coating, without any apparent defects can be observed, together with an uniform interface. A uniform coating thickness of ~ 15 µm is achieved. The coating thickness was also measured with the coating gauge meter and presented in Table 2. It can be noticed that the coating thickness under all identical conditions are similar, and there are no noticeable changes  www.nature.com/scientificreports/ in the thickness. It is worthy of mentioning that the reported values are an average of five readings. A slight difference in thickness of coatings measured through FE-SEM analysis may be due to the surface preparation required for the test.
Co-deposition mechanism of various reinforcements in Ni-P matrix has been proposed by many researchers. Guglielmi 54 proposed a model containing two steps in which firstly, particles adsorb weakly on the cathode surface by Van der Waals forces and then during the second stage strong adsorption by coulombic forces. This model fails to account for particle size and hydrodynamics of the deposition. Bercot et al. 55 formulated a corrective factor to this model for accounting for magnetic stirring in their study, whereas Bahadormanesh and Dolati modified Guglielmi's model for the deposition of a high-volume percentage of the second phase and carried out a parametric study 56 . Moreover, Fransaer et al. devised a trajectory model in which they presented an analysis of various forces on a spherical particle in a rotating disk electrode system 57 . According to Ceils et al. 58 , the electrodeposition mechanism may consist of five steps; (i), formation of an ionic cloud around the reinforcement particles, (ii) movement of reinforcement particles by forced convection towards the hydrodynamic layer of the cathode, (iii) diffusion of the particle through double layer, (iv) adsorption of the particle along with the ionic cloud at the cathode surface and (v) reduction of the ionic cloud leading to an irreversible entrapment of reinforcement particles in the metal matrix. As per the above discussion, it seems there are mainly three steps involved in the co-deposition of the reinforcement particles, such as TiC during the electrodeposition process; (i) movement of particles from bulk electrolyte to hydrodynamic boundary layer of the cathode which are governed by a combination of forced convection and electrophoresis, (ii) diffusion and adsorption of particles at the cathode due to Van der Waal forces, and (iii) permanent incorporation of particles due to the reduction of ionic cloud around the reinforced particle. This three-step phenomenon can be described in the schematic diagram in Fig. 5.
The co-electrodeposited of TiC in the Ni-P matrix was further evaluated with EDS analysis. The EDS analysis of Ni-P and Ni-P-TiC composite coatings containing various concentrations of TiC particles, is presented in Fig. 6a-f. The elemental mapping of Ni-P /TiC composite coatings is shown as an inset of Fig. 6. The presence of titanium (Ti), carbon, (C), Phosphorus (P), and nickel (Ni) confirm the incorporation of TiC particles into the Ni-P matrix. Table 3 shows the weight percentage of various elements in the as prepared composite coatings. As for Ni-P coating, nickel constitutes almost 89.51 wt.% and the remaining is balanced by phosphorus. Introduction and increase of the concentration of TiC powder in the chemical bath does affect the concentration of nickel in the deposit, which appreciably decreases without significant effect over the phosphorus content which remains around 10 wt.% in all the coatings. The titanium content in the deposits increases from 0.39 to 0.84 wt.% when the concentration in the chemical bath is increased from 0.5 to 2.0 g L −1 . However, the excessive weight percentage of carbon can be attributed to the combination of various effects such as presence of carbon in the titanium carbide compound, impurities related to environment and surface preparation for the microscopic analysis. Incorporation of TiC particles can be inferred from the titanium peaks in the EDS plot of 0.5, 1.0, 1.5, 2.0 g L −1 and cross-section of 1.5 g L −1 of TiC. The carbon peak in all the plots can be attributed to the steel substrate's carbon composition due to background interference as previously reported by Pouladi et al. 59 . Peaks of iron are also observed in the cross-sectional EDS analysis which can be ascribed to the steel substrate. Further, corresponding EDS elemental mapping results shown as an inset of corresponding compositions depicts the clear distribution of Ni, P, and TiC particles in the Ni-P matrix.
In order to further investigate the microsctructural properties of the deposit, high resolution-transmission electron microscopy analysis were carried out for the Ni-P-2.0 g L −1 TiC. Figure 7 shows the TEM bright field micrographs of electrodeposited Ni-P-2.0 g L −1 TiC composite coating at various magnifications. All the images clearly reveal the presence of a separate second phase of TiC particles within the Ni-P matrix. Figure 7a presents a low magnification micrograph of the composite coating. The excessive darkness is due to the thickness of the coating deposited on the copper grit for TEM analysis. Figure 7b is the enlarged image at the marked location    60 . An irregular dark network is observed in the Fig. 7b which is prevalent to the mid-high phosphorus content within the electrodeposited composite coatings as previously reported 60,61 . Figure 7c is the micrograph at very high magnification presenting the cubical polygonal structure of the reinforced titanium carbide embedded in the Ni-P matrix. The matrix-reinforcement interface can be clearly distinguished as comparatively sharp contrast can be identified in the micrographs. According to literature, titanium carbide particles are reported to have regular polygonal cubical structure 62 . FE-SEM images could not accurately provide the evidence of aggregation or agglomeration of TiC particles during the fabrication of the Ni-P-2.0 g L −1 TiC composite coating. TEM analysis further confirms the agglomeration or aggregation of the cubical polygonal TiC particles, which are visible in Fig. 8 for the Ni-P-2.0 g L −1 TiC. Agglomeration of the particles in composite coatings has been confirmed through TEM micrograph as reported in literature 61,63 .
The surface topography of the electrodeposited Ni-P and Ni-P-TiC composite coatings was investigated through atomic force microscopy (AFM). Three-dimensional images of Ni-P and Ni-P/TiC composite coatings with the various compositions of TiC particles are presented in Fig. 9a-e. It is observed that the Ni-P coatings indicate a relatively smooth surface when compared with the Ni-P-TiC composite coatings. The Ni-P-TiC composite coatings' surface is composed of valleys and intrusions due presence of TiC particles into the Ni-P matrix that provides a rougher texture. The quantitative analysis of surface topography indicates that the addition of TiC particles into the Ni-P matrix has resulted in an increase in the surface roughness. The average surface roughness (Ra) increases with the increasing amount of TiC particles and the average value increased from 6.786 nm (Ni-P coatings) to 33.014 nm (Ni-P/TiC-2.0 g L −1 ), contributing five times enhancement in the surface roughness. Moreover, Rq (root mean square value of the roughness) is also presented which shows the similar trend as the average roughness as presented in the Fig. 9. Furthermore, Rz values also displays the similar increasing trend from 18.6 nm roughness of Ni-P coating to the successive increase upto 53.8 nm, 58.5 nm, 70.2 nm and 77.6 nm for the increase in the concentration of TiC particles of 0.5 g L −1 , 1.0 g L −1 , 1.5 g L −1 and 2.0 g L −1 in the chemical bath. The increase in the surface roughness with an increasing amount of TiC particles can be attributed to the presence of insoluble and hard ceramic particles, which provides jerks and barriers to the free movement of the AFM cantilever tip. These findings are consistent with the previous studies 29,33 .

Mechanical properties. Vickers microhardness. Vickers microhardness results of Ni-P and Ni-P-TiC
composite coatings are presented in Fig. 10. As seen, Ni-P coating's hardness value is around 500HV, which increases to ~ 530 HV and ~ 550 HV on the incorporation of 0.5 g L −1 and 1 g L −1 of the TiC particles, respectively. The hardness value reaches its maximum value of ~ 593 HV at the composition of 1.5 g L −1 . The increase in the hardness is about 19%, which can be attributed to the dispersion hardening effect and improvement in the load-bearing characteristics of the matrix due to the formation of a composite structure, aligned to previously reported literature 64,65 . After reaching to its terminal value, the microhardness decreases with further increase in TiC particles and it decreases to ~ 550 HV at 2.0 g L −1 . A decrease in the hardness value at 2.0 g L −1 can be attributed to the excessive aggregation of the TiC particles in Ni-P matrix, which impairs the load-bearing properties of the Ni-P/TiC composite coatings. This observation is also consistent with previous reports 66 . Nanoindentation. The indentation tests of the Ni-P and Ni-P-TiC composite coatings were performed to have an insight of the mechanical response of the developed coatings. The loading/unloading indentation profiles of Ni-P and Ni-P-TiC composite coatings containing various concentrations of TiC particles are presented www.nature.com/scientificreports/ in Fig. 11. A gradual decrease in indentation depth with an increasing amount of TiC particles in the Ni-P matrix is evident in Fig. 11a. The Ni-P coatings demonstrate an indentation depth of ~ 50 nm, which reduces to 23.67 nm at the composition of 1.5 g L −1 of TiC. The decrease in depth is due to the enhancement in the hardness of the coatings, which is directly associated with the dispersion hardening effect and improvement in the loadbearing properties, as explained previously. It can be further noticed that there is a decrease in the indentation depth of ~ 7 nm at the terminal composition (2.0 g L −1 TiC). This is because of the fact that an excessive amount of reinforcement accumulates in the matrix and thus harms the mechanical properties are in agreement with previous studies 67, 68 . The maximum decrease in the indentation depth is observed at 1.5 g L −1 of TiC due to the uniform distribution of the reinforcing phase in the matrix without any significant agglomeration. The loading/ unloading curves are uniform without any kinks, suggesting that the synthesized coatings are free of cracks

Corrosion behavior
Electrochemical impedance spectroscopy (EIS). The corrosion resistance of the coatings was studied through electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques. The EIS plots (Bode plots) of the substrate (carbon steel), NiP, and NiP-TiC composite coatings containing various concentrations of TiC are presented in Fig. 12a,b. Experimental data were fitted using an equivalent circuit based on a modified Randle circuit. It is composed of two-time constants in cascade assigned to the composite coatings and metal-coating interface exposed at the bottom of conductive paths, as presented in Fig. 13a,b. The various elements in the circuit account for: Rs-electrolyte resistance, Rpo-pore resistance, Rct-polarization resistance, and constant phase elements (CPE1 and CPE2) instead of capacitors to account for surface inhomogeneity. The constant phase elements can be calculated by the following equation 33 :  www.nature.com/scientificreports/ where Q is the admittance and ω is the angular frequency of the alternating signal and n is the exponent of CPE which determines the capacitance nature, i.e., when "n" approaches unity, the CPE approaches to pure capacitance and the element behaves like an ideal capacitor 33 . Referring to Fig. 12, the medium-high-frequency regions of the Bode plot for carbon steel evidence one time constant, while for the coated samples there is a broadening of the phase angle, suggesting two overlapped time constants-the one associated to the composite coating and another to the interfacial phenomena at the bottom of pores formed in the coating. The magnitude plot indicates that the corrosion resistance of the carbon steel sample is very low ~ 270 Ω cm 2 , a value that was obtained after fitting the experimental data using the proposed equivalent circuit (Fig. 13a). Ni-P coatings show an improvement in the impedance value of one order of magnitude which can be ascribed to the formation of the hypophosphite layer due to electrochemical reactions of the salt solution with the surface of Ni-P coating 70,71 . The inclusion of secondary phase TiC particles in the Ni-P matrix further changes the impedance response, leading to the broadening of the phase angle plot. This trend indicates, by the one hand, a more protective composite coating (shift towards higher frequencies) and, on the other hand, the presence of other processes (decreased corrosion activity) as previously reported in literature 33,42 . The increased impedance in the composite coatings can be attributed to the reduction on the number active corrosion sites due to the occupancy of inert and corrosion-resistant TiC particles. The Ni-P-0.5 g L −1 TiC showed almost doubled impedance values compared to a simple Ni-P coated sample (Fig. 12). An increase in the concentration of TiC particles from 0.5 g L −1 up to 2.0 g L −1 has successively increased the corrosion resistance and the maximum impedance values for Ni-P-2.0 g L −1 TiC reaches 23 kΩ cm 2 showing an improvement of ~ 92% when compared to Ni-P coatings. An increase in the pore resistance can be due to  www.nature.com/scientificreports/ the presence of TiC particles in the pores of Ni-P matrix that decreases the number of conductive paths and increases the surface roughness as observed in AFM results 49 . Improvement in the polarization resistance can be related to the successive increase in the reinforcement of TiC particles in the Ni-P matrix which hinders the electrolyte from reaching the substrate, decreasing the number of active sites and hence providing additional protection against corrosion 33,42,49 . Figure 14a depicts the Nyquist plots for carbon steel (substrate), Ni-P and Ni-P-TiC composite coatings containing various concentrations of TiC particles. Nyquist plots of Ni-P coatings and Ni-P-TiC composite coatings demonstrate distinct capacitive loops. The experimental plots for the coated samples were fitted using the two-time constant equivalent electric circuit described in Fig. 13b and the fitting goodness is represented in Fig. 14 in the Nyquist plots. The capacitive loop diameter evidences a successive increase, confirming the higher corrosion resistance in the presence of TiC particles. Figure 14 depicts the evolution of the pore resistance and polarization resistance over time. The incorporation of TiC particles in the Ni-P matrix increases the pore resistance in the coating and acts as a barrier by that delays electrolyte uptake. The decrease of the active surface area is responsible for the increase in the polarization resistance (Rct) as shown in Fig. 14b. Moreover, increasing the concentration of TiC particles in the chemical bath leads to a decrease in the active region and, therefore, increases the corrosion resistance of the composite coatings. The enhancement in the corrosion resistance of the NiP coating in the presence of various concentrations of TiC can be enumerated by the combined effect of (i) Inert TiC particles reduce the active area in the NiP alloy (ii) TiC particles are assumed to block the pores by filling them and restricting the diffusion of the Cl − ions towards the metal surface and (iii) double-layer capacitance reduces. These findings are consistent with the previous studies 9, 33,42,49 . Potentiodynamic polarization analysis. The corrosion resistance of the carbon steel, Ni-P, and Ni-P-TiC composite coatings containing various concentrations of TiC particles was also studied by d.c. potentiodynamic polarization employing a scan rate of 0.167 mV s −1 as shown in Fig. 15. Electrochemical parameters such as corrosion potential (Ecorr), corrosion current density (Icorr), anodic Tafel slope (βa), and cathodic Tafel slope (βc) were extrapolated from the fitted curve and tabulated in Table 4. Moreover, the corrosion protection efficiency (PE %) was calculated from the formula as reported 33 . PE% = 1-i 2 i 1 where i 1 is the current density of the carbon steel and i 2 is the current density of coated samples. The maximum value of current density (55.94 µA cm −2 ) is observed for carbon steel at a corrosion potential of -533 mV, the most cathodic one observed in Fig. 15. The current density decreases to 38.43 µA cm −2 for the Ni-P coatings and further decreases with increasing concentrations of TiC particles in the Ni-P matrix. Thus, the values of current density decrease to 25.62 µA cm −2 , 7.79 µA cm −2 , 6.49 µA cm −2 and 4.91 µA cm −2 for the 0.5 g L −1 , 1.0 g L −1 , 1.5 g L −1 , and 2.0 g L −1 TiC composite coatings respectively. Moreover, the corrosion potential, becomes slightly more anodic for the Ni-P coatings and increases from ~ − 372 mV to ~ − 312 mV with increasing concentrations of TiC suggesting a slight inhibition of the anodic activity in the presence of the TiC particles in the Ni-P matrix. Interestingly, for the TiC concentrations of 1.0, 1.5 and 2.0 g L −1 , the anodic current density is independent of the content of TiC particles, and significantly lower compared to the Ni-P coating. This trend evidences that the anodic activity is reduced in the presence of the TiC particles (for the 3 highest concentrations). However, the cathodic current density tends to increase as the concentration of particles increases, approaching the values observed for the Ni-P coating and steel. This indicates that the cathodic processes, mainly oxygen reduction, are favored by the presence of TiC particles. The potentiodynamic polarization results show that Ni-P coatings had lower corrosion resistance compared to steel, displaying a corrosion protection efficiency of ~ 31%. In such composite coatings, corrosion often initiates at grain boundaries of the nodules as result of the adsorption of chloride ions. The anodic activity leads to the formation of soluble NiCl 2 which can proceed to formation of pits 72 . The corrosion protection efficiency, consequence of the decreased corrosion current density, increases with the increasing concentration of TiC particles in the Ni-P matrix. The highest corrosion protection efficiency www.nature.com/scientificreports/ (~ 90%) was achieved at a TiC concentration of 2.0 g L −1 . To conclude, the inclusion of TiC particles in the Ni-P alloy matrix has improved the corrosion resistance as the concentration of TiC particles. By the one hand, the presence of particles inhibits the anodic reactions and, on the other hand, it contributes to reduce the number of active sites for the adsorption of chloride ions on the surface defects such as cracks and pores. Enhancement in the corrosion resistance by increased concentration of reinforcement is in good agreement with literature 33,35,36 .

Conclusions
Ni-P-TiC composite coatings containing various concentrations of TiC particles were synthesized using the electrodeposition technique. The amount of TiC particles in the Ni-P matrix has a significant influence on its morphological, structural, mechanical, and corrosion protection properties. The hardness of Ni-P-TiC composite coatings increases with an increasing amount of TiC particles in the Ni-P matrix. However, an excessive amount of TiC particles (2.0 g L −1 ) leads to particles agglomeration and thus reduction in hardness. Electrochemical studies confirm the increased the corrosion protection offered by the Ni-P coatings with an increasing amount of TiC particles. The Ni-P-TiC composite coatings demonstrate superior mechanical and corrosion protection properties when compared to Ni-P coatings suggesting their utilization in many industries such as automobile, marine, electronic, oil, and gas industries.