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Degradation and Protection

Degradation and Protection. What is affecting the materials ?. Definitions. Degradation occurs when a material looses its properties All materials degrade at the surface (to varying degrees) when they enter into contact with … UV Liquids Oxygen.

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Degradation and Protection

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  1. Degradation and Protection Whatisaffecting the materials?

  2. Definitions • Degradation occurs when a material looses its properties • All materials degrade at the surface (to varying degrees) when they enter into contact with … • UV • Liquids • Oxygen

  3. Protection methods attempt to slow down the degradation

  4. 1. Degradation and protection of Wood A) Properties of wood: • Hardness, elasticity, resilience • Low thermal and electric conductivity • Easily shaped and assembled • Light weight

  5. 1. Degradation and protection of Wood • B) Degradation • It can rot, be subject to disease • fungus, insects and micro-organisms can infest the wood. • C) Protection: • By varnishing, heating, painting or treating the wood, we can extend its lifetime.

  6. 2. Degradation and Protection of Ceramics Ceramic is a solid non-metallic material obtained by heating inorganic matter containing various compounds A) Properties • Low thermal and electrical conductivity • Hardness • Resist corrosion • Durable B) By giving a heat treatment, we can reduce its weakness to thermal shock

  7. 3. Degradation and Protection of Metals A) Properties (varies with the metal) • Usually shiny • Good conductors (heat and electricity) • Ductility and Malleability depend on the materials B) Degradation • Corrosion and Oxidation C) Protection: • Coat the metal with a less corrosive metal (Zn, Au, Ag, Ni) • Coat the metal with paint, enamel, grease, resin

  8. Chemical Changes

  9. Chemical Review • 1. Chemical vs. Physical Changes • Gas formation • Release or absorption of energy (light or heat) • Precipitation • Color change

  10. Chemical Review • 2. Types of chemical changes • A) Synthesis vs. Decomposition • B) Photosynthesis vs. Cellular Respiration • C) Oxidation • D) Combustion

  11. Chemical Review • 2. Types of chemical changes • A) Synthesis vs. Decomposition • Synthesis • When 2 or more molecules or elements become one molecule • Decomposition • When 1 molecules is broken down into 2 or more molecules or elements

  12. Chemical Review • 2. Types of chemical changes • B) Photosynthesis vs. Cellular Respiration • Cellular Respiration • What we do • Take in Oxygen • Photosynthesis • Plants (during the day) • Take in Carbon dioxide

  13. Chemical Review • 2. Types of chemical changes • C) Oxidation • Requires Oxygen • E.g. corrosion

  14. Chemical Review with the Particle model • 2. Types of chemical changes • C) Oxidation • E.g. corrosion

  15. Chemical Review • 2. Types of chemical changes • D) Combustion • Requires Oxygen (O2) • Gives off energy

  16. Combustion side note: • Types of combustion: • Slow • Rapid • Requires outside energy input • gives off heat and light that is observable • Spontaneous

  17. Combustion Triumvirate (Fire Triangle) Fuel Oxidation Agent Ignition Temperature

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