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A completely nickel-aluminum-copper (Ni-Al-Cu) layer was obtained through thermal diffusion process on a nickel-aluminum-bronze (NAB) substrate. The cumulative mass loss of the NAB alloy during the cavitation erosion tests was about 6.4 times and 5.5 times as large as that of the Ni-Al-Cu layer in distilled water and 3.5 wt% sodium chloride (NaCl), respectively. Electrochemical measurements under quiescence and cavitation erosion conditions were conducted to investigate the synergistic effects of cavitation erosion and corrosion. The results showed that the synergism had measurable effect on the cavitation erosion-corrosion process for both the NAB alloy and the Ni-Al-Cu layer. The total contribution of the cavitation erosion component including W E and W CIE was more than 80% and W E occupied the largest percentage. Thus, the improved cavitation erosion resistance of the Ni-Al-Cu layer was mainly due to mechanical factors, which implied a homogeneous and refined microstructure and the formation of hardened Ni 3 Al phase. [ABSTRACT FROM AUTHOR]

Highlights: [•] Diffusion coating treatment for Mg alloys in Al-containing molten salts. [•] The diffusion coating process was carried at lower temperatures (280–400°C). [•] The diffusion kinetics of the formed intermetallic coatings were investigated. [•] The interdiffusion coefficients and activation energies for each phase were obtained. [ABSTRACT FROM AUTHOR]

Highlights: [•] SiC particles were coated with α-Al2O3 by sol–gel technology. [•] The Ni/CSp composite was fabricated by electrodeposition. [•] The yield strength of Ni/CSp was increased by more than six times of pure Ni at 600°C. [•] SiC enhanced strength by inhibiting grain growth and interacting with dislocations. [•] Cracking of coated particles demonstrated the result of load transfer strengthening. [ABSTRACT FROM AUTHOR]

Abstract: A continuous Mg–Al intermetallic coating was fabricated on an AZ91D Mg alloy in molten salts in the lower temperature range from 300°C up to 400°C. The coating consists of a single Mg17Al12 intermetallic layer or both Mg17Al12 and Mg2Al3 intermetallic layers, depending on the treatment temperature. In contrast to the conventional powder pack cementation process, active Al atoms can be formed at a lower temperature in molten salts, which contributes to the lower temperature formation of continuous intermetallic layers. The intermetallic layer markedly improves the hardness as well as the corrosion resistance of the AZ91D Mg alloy. Furthermore, the continuous intermetallic layer exhibits passive behaviour in 3.5wt.% NaCl solution, which is attributed to the homogenously distributed intermetallic phases. [ABSTRACT FROM AUTHOR]