1. A. R. Phani and S. Santucci CNR-INFM CASTI Regional Laboratory at Department of Physics - University of L’Aquila, via Vetoio, 67010 Coppito, L’Aquila, ITALY Tel: 0039-0862-433037 Fax: 0039-0862-433033 e-mail: sandro.santucci@aquila.infn.it or phani_ayala@yahoo.com Protective Space coatings for Ti, Al and Mg alloys: Nanoscale materials based on organically modified ceramics Motivation – Objectives Mg and its Space Applications Innovative approach  The main objective of this proposal is to protect space materials from corrosion such as Ti and Mg alloys with nanostructured- multifunctional coatings.  In the proposed system, deposition of nanolayering of inorganic and organic nanocomposite materials embedded with nanoparticles (corrosion inhibitors) with additional functional groups on the surface will be developed.  These nanocomposite materials will be prepared by simple, wet chemical processing system (sol-gel process) at relatively low temperatures (> 150 °C).  The basic structure consists of inorganic network with organic cross-linking or network modifying structural units. A main advantage of this system is the combination of hardness (coming from the high amount of inorganic network structures) and flexibility (coming from the nature and amount of cross linking structures).  This could be possible by covalently bonding the networks leading to stable functionalisation and incorporating the corrosion inhibitor nanoparticles with in these networks to have corrosion resistance properties. CNR-INFM CNR-INFM Sol-gel Process Sol-gel Nanotechnology Applications Project Goals Solution Xerogel film Coating Heating Dense Film substrate Metal Alkoxide (M-O-R) Hydrolysis and Condensation Polymerisation Coating Sol Getting Wet gel Aero gel Extraction of solvent Evaporation Heating Xero gel Dense ceramics Precipitating Uniform particles Spinning Fiber s Furnace Sol-gel Process Uniformity High purity Easy Operation Cost Effective Low temperature Controlled structure Coating on irregular shapes Selective doping ADVANTAGES pH (acid / base) Temperature Water and Solvent Reagent concentration Catalyst Dipping (spinning) speed FACTORS EFFECTING Optical Coatings Chemical Industry Building – construction Technology Aeroneutic Industry Automotive Coatings Solar Technology Aviation Engineering Bio-medical Engineering Functional Thin Films Membranes Protective Films Nano- particles Emulsion Powders Nanostructures Smart Materials Reinforcing Fibers Sol-gel Technology Applications Thin films Powders Fibers Composites  Smart windows  Sun roofs  Capacitors  Semiconductors  Heat insulating  Memory devices  Dispalys  Wave guides  Corrosion  Abrasion  Erosion  Scratch  Anti-adhesion  Anti-finger print  Anti-fouling  Antibacterial  Biosensors  Implant coatings  Gas sensors  Hydrophobic  Photocatalytic  Energy storage  Fuel cells  Solar cells  Laser diodes  Decorative Sol-gel Coatings Applications  Magnesium alloy has a light weight, high thermal conductivity, high dimensional stability, good electromagnetic shielding, high damping characteristics, good machineability and as well as recyclability  These properties make it valuable in a number of applications including automobile, aerospace components, mobile phones, sporting goods, handheld tools, and household equipment  The use of magnesium alloys can significantly decrease the weight of automobiles without sacrificing structural strength  Unfortunately, magnesium alloys have a number of undesirable properties including poor corrosion and wear resistance, poor creep resistance, and high chemical reactivity that have hindered its widespread use in many applications  Magnesium has a number of unique physical and mechanical properties which, depending on strength, safety and weight aspects can be used by automotive, aerospace and electronic goods designers Applications  Light wieght (36% lower than Al)  High strength to weight ratio  High stiffness to weight ratio  Excellent damping capacity  Castability, mechanibility, recyclibility Properties AUTOMOTIVE WEIGHT SAVING AEROSPACE  Fuel consumtion  Emission  Safety  Braking  Dynamic Radical Innovative Approach:  This type of system will be applied on different types of Titanium, Magnesium and Aluminium alloys applicable to aerospace applications.  It has been recognised by the aerospace industries that the degradation of carbon-based materials (organic coatings) in low earth orbit (LEO) is due to the presence of ground state atomic oxygen, ultra-violet radiation and vehicle’s extreme velocity.  The UV radiation that is present in low earth orbit is of adequate energy to cleave organic bonds, which can bring about chain scission and cross-linking reactions in organic polymeric materials. In addition to this, thermal cycling, particulate radiation, vacuum, and micrometeoroids and debris affect organic materials.  In this respect, materials consisting of inorganic/organic (polymer) can offer protection from atomic oxygen as well as UV radiation and high- energy particles via the in situ fabrication of nanophase silicon / metal-oxo clusters.  Siloxane polymers, which have rates of erosion one to two orders of magnitude slower than organic polymers in low earth orbit, have been chosen in the present investigation.  In addition, to slower erosion rates, when exposed to atomic oxygen siloxane polymers form protective silicon oxide barrier.  This provides enhanced atomic oxygen resistance, and will offer a self-healing property if the coating is scratched or etched from the debris.  The silica layer on the surface prevents further degradation of the polymer underneath with increased exposure to atomic oxygen. Background Aerospace Value of a pound in segnment weight saved (Euro) Commercial -------------------- 357 Space ----------------------------- 35.4 Automobile --------------------- 1.78 – 3.2 Fig 1: Schematic diagram of the nanoscale hybrid structure for multifunctional properties for light-weight alloys applied for space applications  The proposed mechanism explains where a space debris erode a part of coating which is self healed by consuming the atomic oxygen present in the space, there by forming a new protective layer which can withstand both atomic oxygen degradation, high energy UV radiation and atomic particles.  Once the coating is exposed to atomic oxygen a protective layer of silicon oxide is formed and with the incorporation of silicon-metal-oxy-clusters the coating should protect against atomic oxygen erosion, high energy particles, and deep UV radiation. Scientific and Technological Objectives that CASTI might pursue in this project: To optimize the developed pretreatment process for light weight alloys prior to the deposition of the nanostructured coatings for better adhesion strength To deposit organic-inorganic hybrid nanocomposites embedded with functional corrosion inhibitor nanoparticles (CeO2, La2O3) To deposit low friction, wear, scratch, abrasion resistant inorganic-polymer hybrid nanostructured coatings as top layer with additional hydro-oleophobic properties to fulfill the objective of the multifunctional coatings. To characterize the deposit or thermally treated coatings for their structural, mechanical, tribological and corrosion (salt spray) and humidity resistance (intermittent, prohesion, and condensation humidity tests) measurements. To optimize the developed nanocomposites embedded with nanoparticles for scale up process upon dealing with the industrial partners in the respective countries in the field of automobile, aeronautic, construction and microelectronic industries. Services offered by CASTI in the project: CASTI will analyze the coated samples as well as corrosion resistance tested (salt spray test) samples by employing full length scale characterization techniques available in the laboratory.