Experimental rig for ice accretion and adhesion strength measurement for air cycle machine system

Air cycle machines (ACM) which are part of the air-conditioning pack in every aircraft, are one such turbomachinery device that can be affected by icing issues particularly at the turbine end. Current ice protection solutions for the air cycle machines use a heating system on the downstream pipe to heat the surface, using electric resistance heaters or hot air coming from the ACM compressor stage. Both solutions require high energy, hence the need to reduce energy consumption through the development of passive energy-saving solutions. Clean Sky 2 ERICE project aims at developing an eco-friendly and cost-effective hydrophobic / ice-phobic solution able to resist ice adhesion in the ACM turbine scroll and its downstream pipe. This paper discusses the implementation of an experimental rig to reproduce the ice formation and accretion conditions within the ACM and a new shear test method to measure the ice adhesion strength on existing and new solutions in the form of coatings. The flow through the ACM turbine exhaust has also been characterized for the first time in published literature. The results from the ice accretion and adhesion tests show that hydrophobic coatings developed for the purposes of ice protection perform better than the current industry baseline material for ACM turbine scroll pipe internal surface. While these coatings could not be used to prevent accretion, they do help in reducing adhesion of ice to the surface.European Union funding: 821301. Clean Sky 2 Joint Undertakin

Comparison between wet deposition and plasma deposition of silane coatings on aluminium

Silane coatings are applied to metal surfaces for various purposes, e.g. to form a protective layer against corrosion or to act as a primer for subsequent coating. In this work bis-1,2-(triethoxysilyl) ethane (BTSE) was used as a precursor to deposit coatings on Al 99.99% substrates with three different techniques: dipcoating (water based solution), vacuum plasma and atmospheric plasma. Infrared reflection absorption spectroscopy (IRRAS), X-ray photoelectron spectroscopy (XPS) and field emission gun-scanning electron microscope (FE-SEM) were used to characterise the structure, composition and surface morphology of the silane coatings. The aim of this investigation is to compare the surface and bulk characteristics of the films prepared with the three different methods, in order to get information on how the BTSE molecule is modified by the deposition technique. The results show that films could be deposited by both vacuum and atmospheric plasma, besides the more traditional wet dipcoating. The layers deposited by vacuum plasma can be considered as hybrid organic-inorganic, comparable to the silane layers obtained by dipcoating. Atmospheric plasma treatment, however, leads to the formation of more inorganic films richer in Si-O bonds. XPS and FTIR measurements show the presence of Si-O-Si bonds, while Si-O-Si, Si-O-C, Si-O and Si-CH3 absorption bands are revealed by IRRAS measurements. © 2010 Elsevier B.V.SCOPUS: cp.jinfo:eu-repo/semantics/publishe

Anti-Corrosion performance of a new silane coating for corrosion protection of AZ31 Magnesium alloy in Hank’s solution

Mg alloys can be used as bioresorsable metallic implants. However, the high corrosion rate of magnesium alloys has limited their biomedical applications. Although Mg ions are essential to the human body, an excess may cause undesirable health effects. Therefore, surface treatments are required to enhance the corrosion resistance of magnesium parts, decreasing its rate to biocompatible levels and allowing its safe application as bioresorbable metallic implants. The application of biocompatible silane coatings is envisaged as a suitable strategy for retarding the corrosion process of magnesium alloys. In the current work, a new glycidoxypropyltrimethoxysilane (GPTMS) based coating was tested on AZ31 magnesium substrates subjected to different surface conditioning procedures before coating deposition. The surface conditioning included a short etching with hydrofluoric acid (HF) or a dc polarisation in alkaline electrolyte. The silane coated samples were immersed in Hank's solution and the protective performance of the coating was studied through electrochemical impedance spectroscopy (EIS). The EIS data was treated by new equivalent circuit models and the results revealed that the surface conditioning process plays a key role in the effectiveness of the silane coating. The HF treated samples led to the highest impedance values and delayed the coating degradation, compared to the mechanically polished samples or to those submitted to dc polarisation

Fully printed flexible and disposable wireless cyclic voltammetry tag

A disposable cyclic voltammetry (CV) tag is printed on a plastic film by integrating wireless power transmitter, polarized triangle wave generator, electrochemical cell and signage through a scalable gravure printing method. By proximity of 13.56 MHz RF reader, the printed CV tag generates 320 mHz of triangular sweep wave from +500 mV to −500 mV which enable to scan a printed electrochemical cell in the CV tag. By simply dropping any specimen solution on the electrochemical cell in the CV tag, the presence of solutes in the solution can be detected and shown on the signage of the CV tag in five sec. 10 mM of N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD) was used as a standard solute to prove the working concept of fully printed disposable wireless CV tag. Within five seconds, we can wirelessly diagnose the presence of TMPD in the solution using the CV tag in the proximity of the 13.56 MHz RF reader. This fully printed and wirelessly operated flexible CV tag is the first of its kind and marks the path for the utilization of inexpensive and disposable wireless electrochemical sensor systems for initial diagnose hazardous chemicals and biological molecules to improve public hygiene and health

Corrosion Mechanism Suggested Based on Electrochemical Analysis and SVET for Uncoated Tinplate and Post Coated With a Hybrid Film

<div><p>The tinplate, used in the packaging sector and formed from a metal substrate, comprises a steel base which has undergone a surface treatment to produce a thin layer of FeSn2, a tin layer and an oxide tin layer. Currently, packaging using surface treatment is based on the use of chromates because these metals provide an excellent corrosion resistance. Nontoxic alternatives to pre-treatments have been developed in recent years to replace the chromate process. The aim of this work is to analyze the performance of a new hybrid organic-inorganic film obtained from sol-gel consisting of the alkoxide precursors 3-(Trimethoxysilylpropyl)methacrylate (TMSM) and tetraethoxysilane (TEOS) with the addition of cerium nitrate with the scanning vibrating electrode technique (SVET), and electrochemical and morphological characterizations. Moreover, the evolution of the corrosion of the substrate was evaluated to propose a mechanism of corrosion. The results showed a galvanic coupling between the Sn/SnO2 coat (cathode) and the defects exposed at the ferrous base (anode). The organic-inorganic hybrid film containing a cathodic corrosion inhibitor was able to retard the corrosion of the tinplate.</p></div