Formation of a photocatalytic WO3 surface layer on electrodeposited Al–W alloy coatings by selective dissolution and heat treatment

In this study, we explored the feasibility of WO3 surface layer formation on electrodeposited Al–W alloy coatings by selective dissolution and heat treatment, with the aim of providing corrosion-resistant Al–W alloy coatings with photocatalytic self-cleaning properties under visible light illumination. The selective dissolution of Al and oxidation of residual W was carried out by immersing Al–W alloy films in an aqueous solution of nitric acid. A nanostructured H2WO4·H2O surface layer was formed on the alloy film by this process. The H2WO4·H2O layer was dehydrated to WO3 by heat treatment, yielding a multilayered WO3/Al–W alloy film with an approximately 300 nm thick WO3 layer. The WO3/Al–W alloy film exhibited photocatalytic self-cleaning, as demonstrated by the photodegradation of stearic acid and methylene blue. We also confirmed that selective dissolution and heat treatment did not significantly diminish the corrosion resistance of the Al–W alloy films.

On the Issue of Predicting the Strength Characteristics of Dispersed-Hardened Polymeric Composite Materials at the Design Stage of Engineering Products

In the article a technique is provided that allows to optimize the process of choosing a rational composition of particulate filled polymer composite materials (PFPCM) based on the estimation of specific adhesive energy. Specific adhesive energy is calculated assuming the oriented surface layer formation and using a structure of representative volume. Strength tests for a variety of PFPCMs were conducted. Comparison of analytical results with the results of strength tests showed that that the higher the value of the specific adhesion energy that the system possesses, the higher its strength characteristics. Thus, this technique provides an assessment of strength characteristics of PFPCM based on data on its granulometric composition, filling ratio and type of binder.