Effect of carbonate additive on the microstructure and corrosion resistance of plasma electrolytic oxidation coating on Mg-9Li-3Al alloy

Carbonate was added to the silicate system electrolyte to improve the corrosion resistance of the plasma electrolytic oxidation coating on Mg-9Li-3Al(wt%,LA93)alloy.The influences of carbonate on the morphology,structure,and phase composition of the coating were investigated by scanning electron microscopy,energy dispersive spectrometry,X-ray diffraction,and X-ray photoelectron spectroscopy.The corrosion resistance of the coating was evaluated by electrochemical experiment,hydrogen evolution,and immersion test.The results showed that the addition of carbonate resulted in a denser coating with increased hardness,and the corrosion-resistant Li_(2)CO_(3) phase was formed.Electrochemical experiments showed that compared with the coating without carbonate,the corrosion potential of the carbonate coating positively shifted(24 mV),and the corrosion current density was reduced by approximately an order of magnitude.The coating with carbonate addition possessed a high corrosion resistance and long-term protection capability.

Biobased materials for food packaging

Consumers prefer foods that are healthier with high quality and safety.Food packaging are de-manded to effectively extend the shelf-life,preserve the nutrients and decrease the microbial contamination during the transport and storage of food.With the increasing concern on the envi-ronmental impacts caused by food packaging wastes,sustainable and green packaging are highly demanded to minimize the harmful effects of food packaging waste on the environment.Bio-based materials are derived from sustainable and renewable biomass,instead of finite petrochemicals.The applications of bio-based materials for food packaging are highlighted in this review.The emphasis is placed on the categories of related biobased materials,their characteristics and ad-vantages for food packaging,as well as the strategies used to improve their performances.Though a lot of trials have been done on biobased materials for food packaging,further attempts to im-prove their performances,understand the functioning mechanisms and develop greener methods for the production,processing and destiny of these bio-based materials are still highly needed for the future research.