In this study, dicalcium silicate (Ca 2 SiO 4 ) coatings were deposited on stainless steel substrates by atmospheric plasma spraying. Salt spray and immersion tests were carried out to evaluate corrosion performance and XRD, SEM, and EDS were used to analyze phase composition and microstructure. During corrosion testing, calcium carbonate crystals appeared on coating surfaces and the pores were filled with hydration products, producing denser coatings. Potentiodynamic polarization curves and electrochemical impedance spectroscopy plots indicated that the corrosion resistance of the coatings increased after immersion in saltwater and artificial seawater, and in the latter case, a silica-rich layer was observed between the coating and the calcium carbonate crystals.

The aim of this study is to characterize the mechanical behavior of wire-arc sprayed Zn-Al coatings and correlate the results with microstructure via computational techniques. High-resolution microstructural images obtained by SEM were imported into NIST-developed FEA software, which calculates macroscale properties based on user-selected features such as voids, pores, cracks, and splat boundaries. To assess the validity of the approach, elastic modulus was measured various ways and the results compared to the simulated value. Resonant frequency analysis provided the most accurate measurement, which was found to be closest to the simulated value.

In recent studies, crack formation was observed in oxidized areas of wire-arc sprayed Zn-Al coatings. As corrosion tests show, these cracks allow electrolyte to penetrate the coating, reducing effective service lifetime. Wire-arc sprayed coatings usually exhibit tensile residual stresses with the potential to cause such cracking. To determine the extent of that potential, the stress state of Zn-Al coatings was measured and correlated with corrosion test results. Residual stress was obtained using the sin2ψ method based on XRD analysis and the results are combined with those of previous studies, forming a hypothesis for the root cause of crack formation in wire-arc sprayed Zn-Al coatings, its effects, and its control.

Ceramic coatings are often applied to metallic substrates using a bond coat to promote adhesion. The corrosion environment between the substrate and ceramic layer can be very harsh due to the absence of dissolved oxygen, high concentrations of corrosive electrolytes, and galvanic and crevice corrosion mechanisms within the bond coat itself. This study assesses the performance of several bond coats in sulfuric acid, including plasma sprayed tantalum and HVOF sprayed NiCr, Hastelloy C, and Ultimet. The bond coats were deposited on Hastelloy substrates and covered with a Cr 2 O 3 topcoat. Electrochemical polarization and open circuit potential measurements were recorded and coating microstructures were examined before and after the corrosion tests. Plasma sprayed tantalum exhibited the best corrosion resistance at room temperature, followed by HVOF sprayed Hastelloy C.

This paper describes a method for producing textured surface layers on vacuum chamber components that act as particle traps. The novel textures consist of a stainless steel core produced by direct energy deposit laser cladding covered with a twin-wire arc sprayed aluminum film. The process has been qualified for 20 nm and older IC architectures and is now implemented in production equipment. It has been proven to significantly increase preventive maintenance intervals, reduce particle levels, and enhance yield.