Traditional and Innovative Materials for Buildings PDF

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2 3 Traditional and Innovative Materials and Architecture Materials and Architecture Materials for Buildings Often shapes are strongly influenced by the chosen material… Often shapes are strongly influenced by the chosen material… Introduction to the materials for architecture and their properties …stone…. …wood…. Prof. Sara Goidanich Good compression resistance, poor traction and flection Dip. di Chimica, Materiali e Ingegneria chimica “G.Natta” Interesting ratio weight/resistance [email protected] resistance Tel. 02.23993148 - http://midar.chem.polimi.it/ Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148 4 5 7 Materials and Architecture Materials and Architecture Evolution of the materials Often shapes are strongly influenced by the chosen material… Often shapes are strongly influenced by the chosen material… From natural materials to materials’ chemistry and polymers: more than 100.000 available materials! …steel…. …reinforced concrete…. Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148 Why studying materials? 8 Why studying materials? 9 Evolution of Materials Venezia - San Marco Firenze – Santa Maria Novella Materials have constituted a physical resource to humans since the beginning of mankind going back more than 50 000 years. Italian Pavilion, Expo 2010, Shanghai shows two basic properties, strength and density, are shown as an example, since they are fundamental to Before the Industrial Revolution: After the Industrial Revolution: performance ETFE (Ethylene tetrafluoroethylene), transparent Stone, binders, wood, glass and metals concrete, smart glass, hybrid materials… Mike Ashby, 2015 Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148  Evolution of Materials Evolution of Materials Evolution of Materials By the peak of the Roman empire, around 50 BC, the area occupied by The progress thereafter was slow: 1500 years later not much has Even 500 years after that expansion of the occupied area of the chart is metals has expanded considerably, giving Rome critical advantages in small; aluminium only just creeps in. weaponry and defence changed, although, significantly, cast iron now appears. Mike Ashby, 2015 Mike Ashby, 2015 Mike Ashby, 2015 Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148 Evolution of Materials Evolution of Materials Evolution of Materials Then things accelerate. By 1945 the metals envelope has expanded considerably and a new envelope – that of synthetic polymers – now occupies a significant position York Minster, Space Center, York, UK. Leicester, UK. N. Grimshaw Architect 21st century Pre-industrial revolution - Post-industrial revolution - Stone, wood, glass ETFE (and thousands more) Mike Ashby, 2015 Mike Ashby, 2015 www.teachingresources.grantadesign.com Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148 22 Products, not materials? Unfamiliar materials used in new products Aims Today architects and structural engineers specify products, not materials. The performance of these products depends on the properties of the materials of which To provide basic knowledege for the selection and use of they are made. A working knowledge of material properties can assist the designer Apartment Building, Munich, Germany. Thomas Herzog, Architect. materials for architectural applications in aligning anticipated behavior with functional needs – and ignorance of them can lead to missed opportunities and mistaken choices Requirement SELECTION Shape, property (application) Suitable materials Production technology An appropriate and aware selection of the materials derives Silica aerogels allowing….. Translucent walls with high thermal resistance from the precise knowledge of their characteristics: Low-e laminated glass Gypsum and glass fiber composite board used as exterior sheathing. Technical datasheet, materials collections, books, software www.teachingresources.grantadesign.com www.teachingresources.grantadesign.com Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148  23 24 25 The building: three semi-indipendent systems… The building: three semi-indipendent systems… … which require different materials Contemporary building performance is  To carry vertical loads to foundations FUNCTION MATERIAL dependent on the whole-building  To resist to horizontal loads  To carry vertical loads to foundations Reinforced concrete Structure Structure  To resist to dynamic loads (e.g., wind)  performance of semi-autonomous To resist to horizontal loads Cast iron, steel systems (superstructure, exterior  To resist to heavy overload (earthquakes)  To resist to dynamic loads (e.g., wind) wood  To assure service lyfe  To resist to heavy overload (earthquakes) Bricks, clay envelope, interiors and building services).  To assure service lyfe Stone Each system provides a particular set of  Air circulation  Air circulation functions.  Heat transmission (thermal insulation) Glass External shell External shell  Heat transmission (thermal insulation) Alluminum The complete list of functions depends on  Permeability: water, vapour  Permeability: water, vapour Silicon, neoprene  Radiation transmission  Radiation transmission Fibres and insulating building size and type (residence,  Acustic insulation  Acustic insulation foams commercial, industrial).  Superficial finishing  Superficial finishing Bitumen, glass wool The list is long and requires behavior that  Internal space definition  Internal space definition can only be satisfied with properties from  Chipboard Separation of different climatic areas  Separation of different climatic areas Reinforced gypsum Internal systems every property class – mechanical, Internal systems  Acoustic insulation among internal rooms  Acoustic insulation among internal rooms  Polymers thermal, optical, electrical, acoustic, Superficial finishing  Superficial finishing Textiles, natural fibres  Comfort and healt safety for residents  Comfort and healt safety for residents ecological and environmental, etc. Roof tiles, bricks Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148 27 28 29 Materials’ selection Selection criteria Materials’ collections INPUT: Several conflicting objectives: a compromise needs to be found  Project evaluation (function, limits…)  Typical project requirements:  Summary of the aims (characteristics, perception…) To minimize weigth and comparison with the existing solutions To minimize volum  Curiosity (new solutions to be invented) Objecticves To minimize environmental impact To enhance performance WHERE TO FIND INFORMATION: To minimize costs  Books  each objective determines a judgment parameter. For example: to minimize weigth, P  Databases to minimize cost, C  Technical datasheet Aim: Conflict: a materials which is able to fulfill one of the parameter  Materials collections  may be unsatisfactorily for what concerning the other one  reference (material’s samples, catalogues, databases)  Search and selection of materials in production  selection has to be a compromise Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148 30 31 Materials’ collections Others Materials’ collections… Materials for Politeca: materia: Buildings MATERIOTECA www.materia.nl Mon - Fri 09.30-12.30 - 14.30-16.30 02.2399.7814 Matech: [email protected] www.matech.it  Hosted by Politecnico di Milano, Polo Bovisa  9000 catalogues, 4000 material’s samples Innovathèque: www.innovatheque.fr LIT: What’s a material? MATERIOTECA Material ConneXion®:  Once Hosted by Politecnico di Milano, Polo https://materialconnexion.com/ Leonardo Prof. Sara Goidanich Dip. di Chimica, Materiali e Ingegneria chimica “G.Natta” [email protected] Tel. 02.23993148 - http://midar.chem.polimi.it/ Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148  33 34 WHAT IS A MATERIAL? MATERIALS’ PROPERTIES  Materials are SOLID compounds used in the  Represent the material’s reactions to external chemical production of objects, components and structures and/or physical actions  A material is defined as an aggregate of atoms  Distinctive quality of each material or molecules binded together by chemical or  Sometime they can derive from the possibility to perform physical bonds. It then gain a proper structure laboratory test _Chemical properties so that it can bear mechanical, physical and  They can be directly measured or they be calculated from chemical stresses actions other data  Each material is requested to provide and  They are quantifiable as they have specific measurement exhibit specific properties during its lifetime units 01_Materials properties Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148 _chemical bonds _atomic bonding Chemical bonding COVALENT BOND: materials with covalent bonding IONIC BOND: between atoms with remarkable differences in EN, thus Derive from the sharing of electrons among two or more atoms share electrons among two or more atoms. exchange of electrons occur (instead of sharing) They can be STRONG or weak depending on the bond energy According to the electronegativity difference the As a result: Na + Electronegativity difference determines the type of bond occuring bond can be either pure or polar: Ions are formed (non neutral charges) - Cl STRONG BONDS i.e. SILICA (SiO4) Bond results from attraction of opposite charges WEAK BONDS SILICATE TETRAHEDRAL CHAIN  COVALENT  VAN DER WAALS i.e. sodium chloride (NaCl)  IONIC  HYDROGEN O  METALLIC Due to electrostatic interaction (Dipole-dipole) STRONG BOND Si O O It is a directional bond  very Regular ordered structure  High resistance to  NON DIRECTIONAL BOND stresses O strong bonds but no ductility and low thermal conductivity  IONIC CRYSTALS Water solubility i.e. SOLUBLE Sara Goidanich – [email protected] – tel. 02 2399 3148 01_Materials properties Sara Goidanich – [email protected] – tel. 02 2399 3148 01_Materials properties SALTS Sara Goidanich – [email protected] – tel. 02 2399 3148 01_Materials properties Atomic bonding _atomic structures A solid materials is composed of atoms and molecules which METALLIC BOND: metallic elements due to low electronegativity give up their may be grouped with different levels of order  different valence electrons to form a diffuse “electronic cloud” surrounding the atoms. structures Positively charged atom cores are held together by the mutual attraction of the CRYSTALLINE: nearby diffused electrons producing a strong bond i.e. (ordered and modular structure) METALS STRONG NON DIRECTIONAL BOND High mobility of delocalized electrons AMORPHOUS: i.e.  THERMAL CONDUCTIVITY (disordered structure (liquid)) GLASS  DUCTILITY Regular and highly packed structure due SEMICRISTALLIN: to atoms tendency to compact in the i.e. (both amorphous and crystalline closest configuration  HIGH DENSITY portion are present) POLYMERS Classification of Materials 01_Materials properties 01_Materials properties Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148  45 46 47 MAIN MATERIALS’ CLASSES Solid state materials: type of strucures Properties of building materials A solid materials is composed of atoms and molecules which Essentially, the vast majority of performance requirements for Material’s properties depends on the type of BOND which may be grouped with different levels of order  different architectural materials can be divided between: binds the single elements structures  Load transfer requirements: Three main classes can be defined as a function of the CRYSTALLINE: The ability to sustain the stresses resulting from the elements content and of the bonds among them: (ordered and modular structure) transfer of forces through to the ground and the metals, polymers and ceramic foundations AMORPHOUS: A further class includes composit materials (disordered structure (liquid))  Barrier system requirements: SEMICRISTALLIN: The building must mediate between an unstable Besides the formers one, the so-colled «natural (both amorphous and crystalline exterior climate and the human physiological need for a materials» includes wood, leather, etc… stable interior environment: exterior enclosure + Portion are present) GEL building services Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148 Light or heavy? 48 50 Materials’ properties Traditional & Innovative materials for buildings General properties Physical and chemical  cost properties Density  Density  Thermal conductivity  Electric conductivity Definition: weight per volume unit Mechanical properties  magnetism Density () is the mass of a unit volume of homogeneous  stiffness  Max and Min working material  resistance temperature Unit of measurement: g/cm3  tenacity  …. Optical properties: Material’s density highly correlated to the structure  ductility Materials properties  transparency Metals high density (high atomic number and compact structure) Durability  Depending on the Prof. Sara Goidanich Polymers: low density, made of elements having a low atomic environment Dip. di Chimica, Materiali e Ingegneria chimica “G.Natta” number (carbon, hydrogen, oxygen) and with a rather low compact [email protected] atomic structure 0,9-2,0 g/cm3 Tel. 02.23993148 - http://midar.chem.polimi.it/ Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148 51 52 53 Density And when a material is porous? Porosity (n) Bulk density b  is the degree to which volume if the material is interspersed Lead alloys Copper Low carbon steel is the mass of a unit volume of material in its natural state (with with pores. It is expressed as a ratio of the volume of pores to 10000 Cast iron, gray (flake graphite) pores and voids) that of the specimen. ௩ Density (kg/m^3) Bronze Titanium alloys 5000 Acrylonitrile butadiene styrene (ABS) For most materials, bulk density is less than density Aluminum alloy, wrought (6061, T4) Marble Ethylene tetrafluoroethylene (ETFE)  Porosity is indicative of other major properties of material, such as bulk density, heat conductivity, durability, etc. 2000 Stainless steel Granite Polyester for liquids and materials like glass and metals, these parameters Borosilicate glass (Pyrex) Dense concrete are practically the same  Dense materials, which have low porosity, are used for 1000 Common brick Epoxies Bamboo constructions requiring high mechanical strength Concrete (structural lightweight) Polyethylene (PE) Properties like strength and heat conductivity are greatly  walls of buildings are commonly built of materials, featuring Natural rubber (NR) 500 affected by their bulk density considerable porosity Softwood (pine) parallel to the grain Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148  54 58 Hygroscopicity - Water absorption and permeability MATERIALS FOR THERMAL PROPERTIES Hygroscopicity is the property of a material to absorb water BUILDINGS Thermal characteristic are connected with the vibrations of vapor from air. It is influenced by air-temperature and relative atoms humidity; pores: their types, number and size. Water absorption denotes the ability of the material to absorb If there are thermal variation the material will: and retain water. It is expressed as percentage in weight or of the volume of dry material:  absorb or give energy (heat) ௌ  Change its dimensions ௐ  Transport of energy (heat) within the material Ms = mass of saturated material (g) Thermal properties M = mass of dry material (g) Water permeability is the capacity of a material to allow water to penetrate under pressure. Materials like glass, steel Prof. Sara Goidanich and bitumen are impervious. Dip. di Chimica, Materiali e Ingegneria chimica “G.Natta” [email protected] Tel. 02.23993148 - http://midar.chem.polimi.it/ Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148 60 61 62 THERMAL CAPACITY AND SPECIFIC HEAT HEAT CONDUCTIVITY Thermal diffusivity THERMAL CAPACITY: is the property of a body to absorb heat  described by its specific heat. Heat capacity is an extensive property IS THE ABILITY OF A MATERIAL TO CONDUCT HEAT units m2/s ఘ஼೛ of matter, meaning it is proportional to the size of the system. Units J/K.  Is the ability to transfer heat in a nonsteady state It is influenced by: condition, or transient condition When expressing the same phenomenon as an intensive property, the Nature of material  It measures how well a material allows heat to “diffuse” heat capacity is divided by the amount of substance, mass, or volume, Structure (crystalline or amorphous) through it so that the quantity is independent of the size or extent of the sample. Porosity and character of pores The specific heat capacity, often simply called SPECIFIC HEAT, is  Is a central aspect of tactile quality of materials because it Mean temperature at which heat exchange the heat capacity per unit mass of a material. Units J/(kg K) affects the “feel” of a material  In general if a material conducts heat well it will generally THERMAL CAPACITY is of concern in the calculation of thermal Metals very good - Polymers insulating – stability of walls of heated buildings and heating of a material, e.g. for have high thermal diffusivity Ceramics high variability concrete laying in winter.  Metals feel cold because they take away heat faster than materials with low thermal diffusivity Units W/m·K Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148 63 64 65 There is not just conductivity… Thermal transmittance COEFFICIENT OF THERMAL EXPANSION  also known as U-value, is the rate of transfer of heat (in Thermal expansion is the tendency of matter to change in watts) through one square meter of a structure divided by shape, area, and/or volume in response to a change in the difference in temperature across the structure. temperature, through heat transfer  It is expressed in watts per meters squared kelvin, or When a substance is heated, the kinetic energy of its molecules W/m²K increases. Thus, the molecules begin moving more and usually maintain a greater average separation.  thermal radiation, thermal convection and thermal Materials which contract with increasing temperature are conduction are taken into account in the U-value unusual; this effect is limited in size, and only occurs within  Well-insulated parts of a building have a low thermal limited temperature ranges convective boundary layer rising from a girl. transmittance whereas poorly insulated parts of a building The degree of expansion divided by the change in temperature (Image courtesy of Gary Settles, Penn State University) Typical convection behavior in buildings. Left, have a high thermal transmittance. convection against a heated or cooled surface. is called the material's coefficient of thermal expansion Right, convection above a point source such as a lamp, human or computer Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148  66 68 69 COEFFICIENT OF THERMAL EXPANSION Maximum service temperature: Tmax Minimum service temperature Tmin The coefficient of thermal expansion describes how the size Tmax of an object changes with a change in temperature. Specifically, it measures the fractional change in size per IT IS NOT THE MELTING TEMPERATURE Tmin degree change in temperature at a constant pressure. Maximum temperature to which the material can Temperature below which the material becomes CONTINUATIVELY work WITHOUT DETERIORATING fragile or in any case unreliable Several types of coefficients have been developed: volumetric, area, and linear. or DEFORMING For solids, one might only be concerned with the change along a It means different for the various material families length, or over some area. because loss of service occurs in diverse ways 1 L Very high for metals and ceramics (high melting  L T temperature) If the body is constrained so that it cannot expand, then internal stress will be caused or increased by an increase in Not very high for polymers, in some cases quite close temperature. to room temperature (glass-transition temperature Tg ) Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148 70 71 72 FIRE RESISTANCE REFRACTORINESS FROST RESISTANCE Fire resistance: is the ability of a material to resist the action denotes the ability of a material to withstand prolonged action of denotes the ability of a water-saturated material to endure of high temperature without any appreciable deformation and high temperature without melting or losing shape. Materials repeated freezing and thawing with considerable decrease of substantial loss of strength. resisting prolonged temperatures of 1580°C or more are mechanical strength. Fire resistive materials are those which char, smolder, and known as refractory Under such conditions the water contained by the pores ignite with difficulty when subjected to fire or high increases in volume even up to 9 per cent on freezing. Thus temperatures for long period but continue to burn or smolder the walls of the pores experience considerable stresses and only in the presence of flame, e.g. wood impregnated with may even fail. fire proofing chemicals. Non-combustible materials neither smolder nor char under the action of temperature. Some of the materials neither crack nor lose shape such as clay bricks, whereas some others like steel suffer considerable deformation under the action of high temperature. Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148 78 Examples of thermal properties MATERIALS FOR Optical properties BUILDINGS Interaction between matter and electromagnetic waves VISIBLE light Total incident radiation Reflected radiation Semi transparent material Absorbed radiation Optical properties Transmitted radiation I reflected I Absorbed I Transmitted Prof. Sara Goidanich   1 Dip. di Chimica, Materiali e Ingegneria chimica “G.Natta” I0 I0 I0 [email protected] Tel. 02.23993148 - http://midar.chem.polimi.it/ Mike Ashby, 2015 Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148  79 80 81 Optical properties Reflectance Materials and transparency Reflectance fraction of incident electromagnetic power that is reflected Fraction of incident light that is reflected  Amorphous materials they can be transparent Absorbance fraction of incident electromagnetic power that is absorbed If the surface is rough, the solar light will have different angle of  Glasses and amorphous ceramics transparent Transmittance fraction of incident electromagnetic incidence with consequent reflection in to different directions  Metals and most of ceramics matt power that is transmitted through a (diffused reflection) that is perceived by a mitigation of light sample  Metals Reflect light intensity (diffused light or ). This is the reason why a frosted glass appears white in color  More complex is the situation of polymers. In general to be They depend on wavelength, transparent they must be quite amorphous, but presence of nature of material and on additives or fillers, dimensions and shape of chains can also state of its surface influence transparency Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148 83 84 The acoustic The acoustic environment The acoustic environment environment Sound is produced by mechanical (kinetic) energy that is For centuries, theater designs were mainly based on the propagated through an ‘elastic’ medium by vibration of the design of different geometric forms. molecules of the medium. By elastic, we are referring to any medium that has a compressible component; fluids such Replacing geometric form as the determinant of acoustic as air are obviously elastic, but solid substances such as design, materials emerged as the predominant factor. concrete also contain interstitial air spaces that can propagate This influence comes from the multiple roles played by the sound. material property of absorptivity, which is an indication of how much kinetic energy the material can absorb from the pressure The origin of sound can be any disturbance (also known as pulses, thereby diminishing their amplitude. a source) that produces a displacement of the surrounding medium. If we cover a concrete wall with wood paneling, we will Prof. Sara Goidanich change the acoustic qualities in the space in a very predictable Dip. di Chimica, Materiali e Ingegneria chimica “G.Natta” way. [email protected] Tel. 02.23993148 - http://midar.chem.polimi.it/ Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148 85 94 Acoustic properties MATERIALS FOR An acoustic wave that hits a material is partially: BUILDINGS Reflected (for material reflection and vibration) Dissipated (heat, friction) Transmitted Environmental impact and Cost Soundproofing by Damping by:  absorption: Absorption will reduce the overall sound level, whereas redirection makes unwanted sound harmless Other properties  redirection (reflection or diffusion). Prof. Sara Goidanich Dip. di Chimica, Materiali e Ingegneria chimica “G.Natta” [email protected] Tel. 02.23993148 - http://midar.chem.polimi.it/ Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148  98 99 DURABILITY INTERACTION MATERIAL/ENVIRONMENT Physical actions  The interaction material/exposition  Temperature CAUTION environment has to be considered as it will affect  Fire the entire lifecycle of the material  Water ALL PICTURES IN THIS FILE BELONG TO THE PHOTO  Radiation ARCHIVE OF TEACHERS AND COLLEAGUES OR THEY  Knowledge of the chemical/physical characteristics  Erosion/abrasion WERE ACQUIRED FROM BOOKS AND MAGAZINES OR of the material  Elctrical fields DOWNLOADED FROM WEBSITES: ... THEREFORE, THEY ARE PROTECTED BY COPYRIGHT.  Knowledge of the environmental characteristics Chemical actions THEY CAN ONLY BE USED IN UNIVERSITY TEACHING  Acids ENVIRONMENT AND FOR NO REASON THEY CAN BE  Alkali REPRODUCED AND DISCLOSED IN ANY OTHER WAY.  Environment  physical, chemical, electrochemical ACTIONS Electrochemical actions  Corrosion Sara Goidanich http://midar.chem.polimi.it Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148 Sara Goidanich – [email protected] – tel. 02 2399 3148