X-ray Diffraction Patterns Of Coatings Research Articles

Comparison of corrosion and antibacterial properties of Al alloy treated by plasma electrolytic oxidation and anodizing methods

Plasma electrolyte oxidation (PEO) and anodizing coatings were produced on 7075 Al alloy and compared together. Surface and cross section morphology of the coatings were studied by field emission scanning electron microscope. Phase compositions of coatings were analyzed by the X-ray diffraction Technique. Tafel polarization and immersion tests were done in 3.5.%wt NaCl solution to evaluate the corrosion properties of the coatings and substrate. The antibacterial activity of coatings was evaluated against E. coli bacterium. The PEO and anodized coatings had a completely different surface morphology and microstructure. The PEO coating was not affected by substrate surface features. Coatings cross sectional analysis showed that PEO coating had a dense barrier inner layer and a porous outer layer and it was less uniform in thickness than anodized coating. X-ray diffraction patterns of coatings demonstrated that PEO coating is mainly consisted of a crystalline γ-Al2O3 phase, while in the case of anodized coating no crystalline phase was observed which suggested that it composed of an amorphous phase. Corrosion resistance of 7075 Al alloy were improved after both coating treatments but PEO coating exhibited superior corrosion properties compared to anodized coating because of the crystalline barrier layer. Also, the presence of Silicon in PEO coating resulted in better antibacterial activity than anodized coating.

Microstructure, Mechanical, and Scratch Resistance Properties of TiAlCrNbN-Graded Composite Coating Deposited on AISI H13 Steel Substrate with Pulsed DC Closed Field Unbalanced Magnetron Sputtering Method

Structure and adhesion properties of TiAlCrNbN coatings were investigated. These coatings were deposited onto AISI H13 steel substrate using pulsed dc closed field unbalanced magnetron sputtering at different deposition parameters including duty cycle, bias voltage, and working pressure. The coatings have been characterized by X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. The TiAlCrNbN-graded composite coatings have a dense and columnar structure. The X-ray diffraction patterns of coatings exhibited predominantly c-TiAlCrN, h-NbN, and h-TiAlN reflections. Scratch resistance test showed that the highest adhesion strength was attained as 68 N at 2.5 μs duty time, 100 V bias voltages, and 3 × 10−3 Torr deposition parameters. The lowest adhesion strength was obtained as 55 N at 0.5 μs duty time, 50V bias voltage, and 2 × 10−3 Torr deposition parameters.

Adhesion and fatigue properties of Ti/TiB2/MoS2 graded-composite coatings deposited by closed-field unbalanced magnetron sputtering

In this study, Ti/TiB2/MoS2 graded-composite coatings were deposited by the closed-field unbalanced magnetron sputtering (CFUBMS) technique. The structural properties of the Ti/TiB2/MoS2 graded-composite coatings were analyzed by energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM) and X-ray diffraction (XRD), and the hardness of the coatings was measured using a microhardness tester. The adhesion and fatigue properties of the coatings were evaluated via a scratch test in two modes. A sliding-fatigue multimode operation was used that involved multi-pass scratching in the same track at different fractions of the critical load (unidirectional sliding), and a standard mode with progressive loading was also utilized. Failure mechanisms are discussed according to microscopic image examinations of the scratch tracks. The Ti/TiB2/MoS2 graded-composite coatings have a dense and non-columnar structure. The X-ray diffraction patterns of coatings exhibited predominantly MoS2 (002) and TiB2 (100) reflections. The target currents significantly affected the thickness and hardness values of coatings. The adhesion and fatigue resistance of coatings improved with increases in hardness and thickness and with decreased Ti/Mo and S/Mo ratios.

A new compound containing five components: 17.2CaO·O.8K 2O·6SiO 2·3SO 3·CaF 2

On examining the X-ray diffraction patterns of coatings from the calcining zone of different cement kilns, some lines not attributable to any of the known compounds were found. Through successive attempts it was possible to synthesize a compound having formula 17.2CaO·O.8K 2O· .6SiO 2·3SO 3·CaF 2 whose main lines corresponded to the unknown ones found in the coatings.