Corrosion Validation

• Independent Variable


  The type of solution mixed with the original material to show different levels and effects of corrosion
• Dependent Variable


  The amount of corrosion found on each material
• Controlled Variables


  • The amount of material originally placed into the beaker (metal, copper, iron, etc.)
  • The amount of original liquid placed in the beaker/petri dish
• Procedure


  1. In the initial process we tested one singular nail in each different beaker with separate corroders. They were left for the same amount of time as one another and the disruption and change of process during the 24-hour waiting period was controlled and remained unaffected.

  2. In the second procedure some Petri dishes had two types of materials (nails and copper wire), possibly interacting with each other to cause a more severe or noticeable corrosion from the contact points.

  3. In the second procedure the water temperature was also changed and increased, not simulating the real environment of the maritime body of waters.
• Maritime construction materials protection methods


  • Cathodic Protection
  • Coatings and Linings
  • Corrosion-Resistant Materials
  • Concrete Additives
  • Marine Growth Control
• Cathodic Protection


  Uses sacrificial anodes (zinc, aluminium, magnesium) to prevent corrosion of main structures
• Coatings and Linings


  Application of protective layers (epoxy, polyurethane) to prevent direct seawater contact
• Corrosion-Resistant Materials


  Use of materials like stainless steel and fibre-reinforced polymers that resist corrosion
• Necessity of These Methods

  • Corrosion Control
  • Biofouling Prevention
  • Environmental Resilience
  • Cost Efficiency
  • Safety and Reliability
• Corrosion


  The gradual destruction of materials, usually metals, through chemical or electrochemical reactions with their environment
• How corrosion impacts maritime construction materials

  • High Salinity
  • Marine Organisms
  • Temperature and Humidity
  • Severe Weather Conditions
• Galvanic corrosion


  A type of electrochemical corrosion that occurs when two dissimilar metals come into electrical contact in the presence of an electrolyte, such as seawater
• Galvanic series/Reactivity series


  A list of metals and alloys ranked by their electrochemical potential in a specific environment, typically seawater
• Galvanic series


  • Cathodic (Noble) End
  • Anodic (Active) End
  • Intermediate Metals
• Sacrificial anode


  A highly reactive metal used to protect less reactive metal surfaces from corrosion through a process called cathodic protection
• How sacrificial anodes work

  • Electrochemical Potential
  • Galvanic Cell Formation
  • Corrosion
  • Protection
• Use of sacrificial anodes on vessels

  • Hull Protection
  • Propellers and Rudders
  • Ballast Tanks
• Common examples of sacrificial anodes


  • Zinc Anodes
• Anion


  A negatively charged ion, formed when an atom or molecule gains one or more electrons
• Cation


  A positively charged ion, formed when an atom or molecule loses one or more electrons
• Anode


  The electrode where oxidation occurs in an electrochemical cell. It is the site of electron loss.
• Cathode


  The electrode where reduction occurs in an electrochemical cell. It is the site of electron gain.
• In electrochemical cells, the flow of electrons is from the anode to the cathode, while the flow of current (conventional) is from the cathode to the anode.
• Rust cannot form without oxygen.
• A physical barrier between iron and the environment helps prevent rust.
• Validity


  Accuracy of the measurement. Ensures meaningful results. Valid tests must be reliable.
• Reliability


  Consistency of the measurement. Ensures stable results. Reliable tests can be invalid.
• Validity ensures a test measure what it should, while reliability ensures it consistently produces the same results.
• To answer the questions regarding the experiments outlined in Procedures A and B, it's essential to first summarize the potential outcomes and then address each question based on those outcomes.
• If the nails in HCl showed significant rust, nails in NaOH and Na₂Cr₂O₇ showed minimal rust, and the nail in NaCl showed moderate rust, the results support the hypothesis that different chemical environments affect corrosion rates. The absence of rust in the boiled water with Vaseline would also support the hypothesis regarding the role of oxygen in corrosion.
• If the bent nail rusted more than the straight nail, and the copper-wrapped nail showed more rust while the zinc-wrapped nail showed less rust, the results would support the hypothesis that physical stress and galvanic coupling affect corrosion rates.
• These experiments demonstrate how environmental factors and physical conditions influence corrosion.
• To improve reliability, ensure that the procedures are followed consistently across multiple trials and by different experimenters.
• To improve validity, ensure that each test condition accurately represents the intended variable (e.g., consistently maintaining reagent concentrations).