The influence of plasma spraying process parameters on microstructure and selected properties of novel NiCr-YSZ composite coating
Tadeusz Kubaszek, Barbara Kościelniak, Marek Góral, Agnieszka Zielińska, Kamila Świerk
Quarterly No. 2, 2026 pages 152-159
DOI: https://doi.org/10.62753/ctp.2026.09.2.2
keywords: plasma spraying, NiCr-YSZ coatings, erosion, wear resistance, hardness
abstract This study investigates the influence of the atmospheric plasma spraying (APS) parameters on the microstructure, mechanical properties, and tribological performance of novel NiCr–YSZ (70/30 wt%) composite coatings. Coatings were deposited onto S235 steel substrates with varying current intensities (300, 500, 700 A) and hydrogen flow rates (4, 8, 12 NLPM). Microstructural analysis revealed that increasing the current to 700 A and hydrogen flow to 8–12 NLPM enhanced particle melting, producing dense coatings with minimal porosity (0.77 vol.%), while reduced hydrogen flow (4 NLPM) resulted in incomplete YSZ particle melting, increased porosity (3.17 vol.%), and a decreased coating thickness (~307 μm). The mechanical and tribological properties correlated strongly with the coating density. The highest hardness (413 HV0.2) and lowest erosion mass loss (0.00703 g) were achieved at 700 A and 12 NLPM. The specific wear rate ranged from 8.25 × 10⁻⁵ to 1.36 × 10⁻⁴ mm³/(N·m), with the lowest value corresponding to the densest microstructure produced at an elevated current intensity. The coatings deposited at 300 A or 4 NLPM exhibited inferior performance due to increased porosity and weak interlamellar cohesion. These findings demonstrate that optimization of the APS parameters to 700 A and 8–12 NLPM enables the production of ultra-dense NiCr–YSZ coatings with superior resistance to erosion and sliding wear, suitable for demanding erosive–abrasive applications.