• The study investigates the effect of three adhesives, polyvinyl alcohol, sodium silicate, and silica sol, on the deposition of SiC particles onto medium carbon steel (CK45) using the TIG process. • Microstructural analysis revealed variations in SiC distribution and decomposition, leading to distinct microstructures influenced by the cooling rates associated with each adhesive type. • Among the adhesives, PVA exhibited superior adhesion characteristics, resulting in a more uniform SiC distribution, increased hardness, and particularly enhanced wear resistance compared to the other binders. In contrast, the cellular and porous structure of the coating produced with sodium silicate led to a deterioration in mechanical performance. • Wear tests demonstrated differences in the coefficients of friction, with samples coated using PVA showing the highest wear resistance and stability, approximately eight times greater than CK45, and comparable to the X120Mn12 alloy. Silicon carbide (SiC) coatings have attracted considerable attention for enhancing the surface hardness, wear resistance, and service life of medium-carbon steels used in severe operational environments. However, the type of adhesive employed in the coating slurry critically dictates particle dispersion, coating integrity, and final mechanical properties. This study investigates the effect of three different adhesives, polyvinyl alcohol (PVA), sodium silicate, and silica sol, on the microstructure and wear behavior of SiC-coated CK45 medium-carbon steel produced via gas tungsten arc (GTA) cladding. The ultimate goal was to assess the feasibility of replacing the X120Mn12 alloy through comprehensive characterization via metallography (optical microscopy), scanning electron microscopy (SEM), microhardness mapping, and pin-on-disk wear tests. Silica sol, while moderately effective, resulted in a partially agglomerated structure with intermediate hardness (962.2 HV) and a wear rate of 18 × 10 −7 g/N⋅m. In contrast, sodium silicate led to highly porous, weakly bonded coatings with almost no martensite formation, attributed to poor thermal conductivity and SiC clustering. Conversely, the use of PVA achieved a uniform particle distribution and effective adhesion, leading to a dense martensitic microstructure and improved cooling rates. Microhardness testing showed an enhancement of up to 5 times in PVA-coated samples compared to the uncoated substrate, while wear tests revealed a significant increase in wear resistance, approximately 8.5 times higher than the base metal and nearly comparable to the X120Mn12 alloy under similar test conditions. Crucially, the structure-property correlation dictated the wear mechanism: the dense PVA coating exhibited mild abrasive ploughing characteristic of dominant two-body wear, whereas the porous structure resulting from sodium silicate promoted material detachment via a dominant three-body abrasive wear mechanism. In contrast, silica sol resulted in intermediate performance. The findings confirm that binder-controlled phase evolution governs the tribological response, positioning PVA-bonded SiC coatings as a highly promising, cost-effective alternative to X120Mn12 for wear-intensive components, contingent upon careful consideration of the operational environment.
Sabouri et al. (Sun,) studied this question.