No abstract

In this work, NiSiCrFeB, WC-Co/NiSiCrFeB, WC-Co, and WC-Cr3C2-Ni coatings were sprayed on rice harvesting blade surfaces using a high velocity oxygen fuel (HVOF) process. Each of the rice harvesting blades was sprayed with one of four coating materials using different spraying durations. The effects of coating materials and spraying durations on the average values of coated blade volume loss, hardness and surface roughness (Ra) were studied through real rice-harvesting field tests. Analysis of variance (ANOVA) and a multiple comparison approach with Tukey’s test were used in order to conduct a comparative performance analysis of the coating materials of rice harvesting blades. The experimental results indicated that the NiSiCrFeB coating exhibited the highest volume loss compared with all others. In addition, the WC-Co-coated blade had significantly greater hardness than those coated with NiSiCrFeB, WC-Co/NiSiCrFeB, or WC-Cr3C2-Ni. The rice harvesting blade coated with either WC-Co/NiSiCrFeB, WC-Co, or WC-Cr3C2-Ni using the shortest spraying duration was recommended for installation in rice harvesting machines.

Purpose This paper aims to compare the wear behavior, surface roughness, friction coefficient and volume loss of high-velocity oxy-fuel (HVOF) sprayed WC–Co and WC–Cr3C2–Ni coatings on AISI 1095 steel with spraying times of 10 and 15 s. Design/methodology/approach In this study, the pin-on-disc testing technique was used to evaluate the wear characteristics at a speed of 0.24 m/s, load of 40 N and test time of 60 min under dry conditions at room temperature. The wear characteristics were examined and analyzed by scanning electron microscopy and energy dispersive X-ray spectroscopy. The surface roughness of a coated surface was measured, and microhardness measurements were performed on the cross-sectioned and polished surfaces of the coating. Findings Spraying time and powder material affected the hardness of HVOF coatings due to differences in the porosity of the coated layers. The average hardness of the WC–Cr3C2–Ni coating with a spaying time of 15 s was approximately 14% higher than that of the WC–Cr3C2–Ni coating with a spraying time of 10 s. Under an applied load of 40 N, the WC–Co coating with a spraying time of 15 s had the lowest variation in the friction coefficient compared with the other coatings. The WC–Co coating with a spraying time of 10 s had the lowest average and variation in volume loss compared to the other coatings. The WC–Cr3C2–Ni coating with a spraying time of 10 s exhibited the highest average volume loss. The wear features changed slightly with the spraying time owing to variations in the hardness and friction coefficient. Originality/value This study investigated tribological performance of WC–Co; WC-Cr3C2-Ni coatings with spraying times of 10 and 15 s using pin-on-disc tribometer by rotating the relatively soft pin (C45 steel) against hard coated substrate (disc).