| LI Jie,WANG Henan,LI Mingsheng,FENG Changjie,ZHANG Chenxi.Effect of Ultrasonic Power on the Microstructure and Properties of Electroless Ni-W-P Coating[J],53(24):120-132 |
| Effect of Ultrasonic Power on the Microstructure and Properties of Electroless Ni-W-P Coating |
| Received:December 15, 2023 Revised:February 28, 2024 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2024.24.011 |
| KeyWord:electroless plating Ni-W-P ultrasonic power microstructure wear resistance corrosion resistance |
| Author | Institution |
| LI Jie |
Shenyang Aerospace University, Shenyang , China |
| WANG Henan |
Shenyang Aerospace University, Shenyang , China |
| LI Mingsheng |
Guangdong University of Technology, Guangzhou , China |
| FENG Changjie |
Shenyang Aerospace University, Shenyang , China |
| ZHANG Chenxi |
Shenyang Aerospace University, Shenyang , China |
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| Abstract: |
| To improve the wear and corrosion resistance of Ni-W-P coatings, the work aims to investigate the effect of ultrasonic power on the microstructure and properties of electroless Ni-W-P coatings. The electroless solution was formulated with NiSO46H2O and Na2WO4 as the main salts, and the Q235 steel was pre-treated and then chemically plated in the ultrasonic equipment with adjustable power in order to obtain the Ni-W-P coating. The hardness, wear resistance and corrosion resistance of the Ni-W-P coating were evaluated by microhardness test, friction wear test and electrochemical test, respectively. The surface, cross-section and abrasion morphology were analyzed by scanning electron microscope and the physical composition of the coating was analyzed by X-ray diffractometer. The experimental results showed that ultrasonic-assisted chemical plating could refine the grain, reduce the holes, improve the densification of the coating, reduce the phosphorus content of the coating, improve the degree of crystallization of the coating, and significantly increase the thickness of the coating within the same time. Scratch experimental tests showed that the ultrasonic power was in the range of 0-90 W, and the bonding strength between the coating and the substrate gradually decreased with the increase of ultrasonic power. When the ultrasonic power was 75 W:the thickness of the coating was 1.61 times of that under no ultrasound, the maximum hardness of the coating was 674.80HV0.05, the coefficient of friction of the plating was 0.38, lower than the coefficient of friction of 0.47 under no ultrasound and the both were lower than the coefficient of friction of 0.58 for Q235 steel. The wear rate of 0.69×10−5 mm3/(Nm) was lower than that of 2.41×10−5 mm3/(Nm) under no ultrasound, and the both were lower than that of 5.28×10−5 mm3/(Nm) for Q235 steel. The wear failure mode of Q235 steel was adhesive wear + abrasive wear, and the wear failure mode of Ni-W-P coating was abrasive wear + fatigue wear. The corrosion current density of 2.23×10−7 A/cm2 was lower than the corrosion current density of 2.21×10−6 A/cm2 under no ultrasound, and the both were lower than the corrosion current density of 2.08×10−5 A/cm2 for Q235 steel. The corrosion potential of −0.362 V was higher than −0.377 V under no ultrasound and the both were higher than −0.611 V for Q235 steel. The total resistance Rt of the coating was 24 338 Ω.cm2, lower than 10 629 Ω.cm2 under no ultrasound, and the both were higher than 592 Ω.cm2 for Q235 steel. The electrochemical polarization test results showed good agreement with the electrochemical impedance test results, and the corrosion resistance of the samples was significantly improved. Ultimately, it is concluded that ultrasonic-assisted electroless plating can refine the grain, reduce the holes, improve the densification of the coating, reduce the phosphorus content of the coating, promote the transformation of amorphous and nanocrystalline to microcrystalline, and improve the degree of crystallization, hardness, abrasion resistance and corrosion resistance of the coating. However, the introduction of ultrasound leads to a decrease in the bonding strength of the coating to the substrate. |
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