• • At 6 g/L TiN, the coating achieved 743.62 HV microhardness, a 120 μm thickness, and grain sizes of 67.28 nm (Ni) and 35.84 nm (TiN), directly extending the service life of copper electrode plates by resisting abrasive wear from pesticide slurries and mechanical cleaning.
• • The corrosion current density dropped to 6.07×10−9 A/cm2 with Ecorr at −0.23 V vs. SCE, and 24 h salt spray produced only minor pits without spalling; this order-of-magnitude reduction in corrosion rate prevents conductivity loss and droplet distribution drift in humid field conditions.
• • Interfacial contact resistance reached a minimum of 6.4 mΩ·cm2, ensuring efficient charge transfer for electrostatic droplet charging; this low resistance is critical because even small increases in contact resistance reduce charging efficiency and pesticide deposition uniformity.
• • The maximum contact angle of 132.82° at 6 g/L TiN creates a hydrophobic surface that reduces droplet adhesion and delays electrochemical corrosion, addressing the persistent problem of liquid film formation that accelerates degradation of copper plates in spray systems.