International Journal of Surface Science and Engineering (5 papers in press)

Regular Issues

• Comparative study of fretting behaviour of nickel-plated and tin-plated copper against brass  
  by Kyungmok Kim 
  Abstract: This article investigates fretting behaviour of tin-plated and nickel-plated copper against brass. Fretting damage is one of critical issues in an automotive battery busbar. Fretting tests with commercial tin-plated and nickel-plated copper busbars were conducted. Two different normal forces (2 N and 4 N) were applied to the contact surface. Frictional force, relative displacement, and electrical contact resistance were simultaneously measured. The energy-based friction coefficient was determined with dissipated energy and actual sliding distance. It was identified that at 2 N, the energy-based friction coefficient of a nickel-plated specimen was approximately 10.7% lower than that of the tin-plated one, while at 4 N, it was approximately 14.4% lower. Fretting tests were interrupted at a critical electrical contact resistance. Then, fretting wear lifetime was defined as the number of cycles at the critical value. It was demonstrated that the nickel-plated specimens exhibited approximately 104% and 131% higher lifetime per unit displacement than the tin-plated specimens at 2 N and 4 N, respectively.
  Keywords: fretting; copper busbar; electrical resistance; nickel-plating; tin-plating; energy-based friction coefficient.
  DOI: 10.1504/IJSURFSE.2026.10081482
   
  
• Water-based superhydrophobic coating based on ODTMS-modified SiO and in synergy with TCNTs/WEP  
  by Bin Du, Xiangtong Jian, Sainan Wang, Kenan Yang, Chenyuan Gao, Jijun Luo, Bangyong Sun, Shisheng Zhou 
  Abstract: Superhydrophobic coatings are promising for self-cleaning, anti-icing, and oil-water separation. However, traditional methods rely on fluorinated compounds and organic solvents, causing environmental pollution, while poor adhesion and low mechanical strength limit their durability. To address these issues, this study develops a fully water-based, fluorine-free coating using ODTMS-modified SiO2 nanoparticles for micro-nano roughness and TCNTs/WEP as an eco-friendly binder. The coating was spray-coated onto substrates, and the sponge was dip-coated. At an optimal 1:1 mass ratio, the coating achieved a water contact angle of 161.7? and retained 153.7? after 500 abrasion cycles, demonstrating excellent mechanical stability. The superhydrophobic sponge exhibited oil adsorption of 48.52-84.92 g/g and maintained > 98% separation efficiency over 20 cycles, and could adsorb both light and heavy oils. This work offers a green, durable, and scalable solution for oily wastewater treatment.
  Keywords: waterborne superhydrophobic coating; superhydrophobic sponge; coating performance; environmental protection; oil-water separation.
  DOI: 10.1504/IJSURFSE.2026.10081593
   
  
• Effects of pin shaft profile modification parameters on the lubrication performance of planetary journal bearings in wind turbine gearboxes  
  by Xudong Chen, Zhongying Xu, Liwen Wang 
  Abstract: Planetary journal bearings in wind turbine gearboxes often suffer from shaft misalignment, edge pressure concentration and asperity contact under low-speed, heavy-load operation. This study proposes a mixed-lubrication model incorporating shaft misalignment, pin-shaft end profile modification, asperity contact and elastic deformation. Hydrodynamic pressure is obtained from the average Reynolds equation, while asperity contact pressure is evaluated using the Greenwood-Williamson model. The influences of modification depth and index on film thickness, pressure and deformation are examined. Results show that end profile modification compensates for end film-thickness loss, shifts the pressure peak away from the axial edge, and substantially lowers edge contact risk. For the representative case with a modification depth of 15 m and a modification index of 1, the maximum contact pressure is reduced by about 95.47% compared with the unmodified bearing. An appropriate depth improves end lubrication, whereas excessive modification weakens the effective load-carrying region; a higher index confines modification to the ends while maintaining central load capacity.
  Keywords: wind turbine gearbox; planetary journal bearing; pin shaft profile modification; misalignment; mixed lubrication; G-W model.
  DOI: 10.1504/IJSURFSE.2026.10081594
   
  
• Three-dimensional CFD and cavitation analysis of earthworm-inspired textured hydrodynamic journal bearings  
  by Chandan Kumar, Asim Gopal Barman, Anindya Malas 
  Abstract: Hydrodynamic journal bearings play a critical role in rotating machinery, where performance is strongly influenced by the bearing surface texture. The present study adopts earthworm-inspired micro-grooved bionic textures on the bearing surface and simulates the lubrication mechanism to evaluate tribological performance with the aim of increasing load carrying capacity and decreasing friction coefficient. A three-dimensional CFD model coupled with the two-phase mixture (Zwart-Gerber-Belamri) cavitation model is employed to simulate the flow field of the textured bearing. Pressure, shear stress, and cavitation behaviour are analysed to examine the governing hydrodynamic mechanisms. Results demonstrate that texture location strongly influences bearing performance, with textures near the minimum film thickness region showing superior performance. Parametric analysis identifies the most favourable texture dimensions, improving load carrying capacity by 24.90% and reducing friction coefficient by 8.32% compared to a plain bearing.
  Keywords: hydrodynamic journal bearing; bionic texture; tribology; eccentricity ratio; friction coefficient.
  DOI: 10.1504/IJSURFSE.2026.10081668
   
  
• Effect of tool steel substrate preheat treatment on the corrosion rate of cold gas sprayed Cr3C2-NiCr coatings exposed to sodium chloride environment  
  by Sanjeev Kumar, Sanjeev Bhandari, Mathanbabu Mathanbabu, S. Karthikeyan, Manpreet Kaur, Gopal Ji Sharma, S. Senthur Prabu, R. Nithya 
  Abstract: Tool steels such as H11 and H13 are widely used in high temperature applications, but susceptible to corrosion in chloride environments; surface modification enhances tool steel durability through advanced coatings. In this study, corrosion characteristics of cold gas sprayed Cr3C2-NiCr coatings deposited on heat treated H11 and H13 tool steel substrates were studied in 3.5 wt.% NaCl solution. The corrosion rates were reduced from 1011 mm/year to 1.7 mm/year for H13 and from 4 mm/year to 1.0 mm/year for H11, resulting in a reduction of corrosion rates of around 84.3% and 75%, respectively. Further, the measured microhardness values also exhibited significant improvements from 240 HV to 800 HV in the dense coatings. Electrochemical studies indicated higher OCP values, and improved polarisation behaviour in coatings deposited on heat treated substrates. Microstructural characterisations revealed dense coating structures with stable Cr3C2 and NiCr phase formation on coatings deposited over both heat treated and as received tool steel substrates.
  Keywords: ool steel; EIS; cold gas dynamic spray; Cr3C2-NiCr; microscopy; microhardness; corrosion rate; structure-property correlation.
  DOI: 10.1504/IJSURFSE.2026.10081851