As a key core component of cotton pickers, the spindle is prone to wear of the hook teeth. This research explores the wear characteristics of the spindle hook teeth of cotton pickers under different working areas. The sampled spindles were cut, the element composition and hardness of the spindle hook tooth coating and substrate were determined, the surface morphology of the spindle hook tooth was characterized, and its wear area and coating thickness were extracted. Results show that the main constituent elements of the coating and substrate are Cr and Fe, respectively, the hardness of the coating is about 1020 HV0.1, and the hardness of the substrate is 470～840 HV0.1. During the field operation, scratches appeared on the surface of the coating, the coating thickness layer gradually decreased, and the coating peeled off as the operating area increased. Afterward, scratches and oxidized particles appeared on the surface of the substrate, the wear rate accelerated, and the wear area gradually increased. The wear of the spindle hook teeth started to appear from the front and rear tooth tips up to the tooth edge, the back of the tooth, and the doffering edge, hence forming a long boot-shaped wear area.

In this study, a dynamic grid mathematical model of scanning electrodeposition coupled with electric field, flow field, temperature field and concentration field was established. The transient distribution of multiple physical fields with different current densities (I was 0.075–0.275 A) and the growth of the coating were investigated. The preparation, morphology characterization and performance testing of nickel-based coatings were carried out. The results showed that the transient distribution of multiple physical fields reflected the deposition rule of the coating, and explains the deposition phenomenon of the coating with an “arch-shaped” distribution in the test. With the increase of current, the thickness of the coating and the degree of the arch increased. The numerical solution was consistent with the experimental law. The hardness, wear resistance and corrosion resistance of the coating increased first and then decreased. When I was 0.175 A (current densities was 700 A/m2), the maximum hardness of the nickel-based coating was 668.88 HV0.1, the minimum wear scar area was 1144.74 μm2, and the maximum equivalent resistance was 10,960 Ω. The temperature and concentration fields had little influence on the deposition process, and changes were only observed on the deposition surface. Electric and flow field distributions had greater influences on the deposition process, were the main reason for “arch-shaped” distribution.