Conventional Surface Treatments
The main conventional surface treatments are
Chemical Pickling & Passivation
Pickling, also called descaling, removes the oxide scale and discolouration, ‘carbonous smut’, caused by welding. This is accomplished with the aid of a hydrofluoric acid based pickling paste.
Passivation is a phrase indicating removal of iron based contaminants with the aid of a nitric acid mix. It reduces the formation of iron-oxide.
It doesn’t result in a passive surface layer!!
Advantages:
- On-site application
- Pump through cleaning
Disadvantages:
- Scanning Electron Microscopy has shown that these chemicals have an etching effect which can greatly the surface roughness profile, resulting in an obvious contamination problem.
- Any residue left after insufficient rinsing can cause corrosion.
- These chemicals are extremely costly to the environment. In some states and parts of Queensland a licence is required to use these acids, and rightfully so. Increasingly stringent environmental laws will soon see to compulsory licensing and controlled waste disposal regulations throughout Australia.
!!Pickling/passivating rinse processes result in chemicals like hydrofluoric and nitric acids being washed down the sewerage system, or worse, the general drainage system!!
ElectroRefinement™ (electropolishing) uses an infinite electrolyte solution; meaning it is used continuously and the rinse water (containing diluted acids) is always recycled back into the system.
Mechanical Polishing
Mechanical or manual polishing smooths and closes the surface with the aid of polishing mops. It aids corrosion resistance by reducing surface roughness. It’s smearing effect however, creates an amorphous, deformed surface layer. Iron-oxides, polishing compounds and other materials become embedded and entrapped in the distorted structure, creating surface corrosion cells.
Advantages:
- Reduces roughness average
- On-site application
Disadvantages:
- Entrapment of contaminants underneath ‘the skin’
- Specialised craft
- Heavy consumable usage
- Shape constraints
- Messy
Conventional surface treatment relies on reduction of Roughness Average which is costly to achieve. ElectroRefinement™ (electropolishing) is a time & cost-effective and superior alternative.
- Electro-Shine
- ABN: 54 287 157 649 Directors: Terry & Laurette Johns
- Address:
- Unit 9 / 60 Fearnley St, Portsmith, Cairns, Tropical North Queensland, Australia
- Postal:
- PO Box 660, Bungalow, Cairns, Queensland 4870, Australia
- Phone:
- 0408 02 06 08 International: +61 408 02 06 08
- Fax:
- (07) 4041 3737 International: +61 7 4041 3737