Residual stresses of α-Al2O3/Ni nano-composite coating prepared by automatic brush plating technique

To remanufacture hard chromium-plated workpiece, nano-Al2O3/Ni-Co composite coatings and Ni-Co alloy coatings are developed using electric brush plating technology. Scanning electron microscopy (SEM) and transmission electron microscope (TEM) are used to analyze the surface morphology, phase structure and wear properties of coatings. The surface morphology of nano-composite coating is more compact. The nano-particles are well-distributed in the coating and bounded tightly with the substrate. The hardness of composite coating is HV1027, increased approximately 38% compared with Ni-Co alloy coating, overtaking the hard chrome plating. The results of sliding wear test shows that the nano-composite coating reduces friction coefficient, increases wear resistance significantly and exceeds the chromium plating.

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Experimental investigation of electrodeposited Ni-Al2O3/ZrO2 nano composite on HSLA ASTM A860 alloy

Surface Topography Metrology and Properties ◽

10.1088/2051-672x/ac396a ◽

2021 ◽

Author(s):

Chandrasekhara Sastry Chebiyyam ◽

Pradeep N ◽

Shaik AM ◽

Hafeezur Rahman A ◽

Sandeep Patil

Keyword(s):

Grain Size ◽

Corrosion Resistance ◽

Composite Coating ◽

Base Alloy ◽

Composite Coatings ◽

Nano Particles ◽

Alloy Sample ◽

Nano Composite ◽

Nano Coating ◽

Nano Composite Coating

Abstract Nano composite coatings on HSLA ASTM A860 alloy, adds to the barrier efficacy by increase in the microhardness, wear and corrosion resistance of the substrate material. Additionally, reduction of delamination of the nano composite coating sample is ascertained. Ball milling is availed to curtail the coating samples (Al2O3/ZrO2) to nano size, for forming a electrodeposited product on the substrate layer. The curtailment in grain size was ascertained to be 17.62% in Ni-Al2O3/ZrO2 nano composite coating. During the deposition process, due to the presence of Al2O3/ZrO2 nano particles an increase in cathode efficiency is ascertained. An XRD analysis of the nano composite coating indicates a curtailment in grain size along with increase in the nucleation sites causing a surge in the growth of nano coating layer. In correlation to uncoated HSLA ASTM A36 alloy sample, a surge in compressive residual stress by 47.14%, reduction of waviness by 32.14% (AFM analysis), upsurge in microhardness by 67.77% is ascertained in Ni-Al2O3/ZrO2 nano composite coating. Furthermore, in nano coated Ni-Al2O3/ZrO2 composite a reduction is observed pertaining to weight loss and friction coefficients by 27.44% and 13% in correlation to plain uncoated alloy respectively. A morphology analysis after nano coating indicates, Ni-Al2O3/ZrO2 particles occupy the areas of micro holes, reducing the wide gaps and crevice points inside the matrix of the substrate, enacting as a physical barrier to upsurge the corrosion resistance by 67.72% in correlation to HSLA ASTM A860 base alloy.

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