Rust prevention practices

Corrosion poses serious challenges in major industries such as infrastructure, transportation, production, mining and manufacturing. Corrosion is the gradual process of degradation of a material, usually a metal, as a result of chemical reactions with environmental substances and conditions. Mackay in Queensland, Australia is widely recognised as the gateway to the Bowen Basin mines and is the single largest coal reserve in Australia, producing approximately 83% of Queensland’s coal. The continued success of the area’s mining industry greatly depends on the observance of rust prevention practices which include abrasive blasting and the application of protective coatings.

Corrosion occurs every day and affects motor vehicles, appliances, energy production and distribution systems and water supply. Rust prevention methods help prevent and minimise damage to save companies from the high costs of repairs and replacement of equipment and facilities. Uncontrolled corrosion can also lead to numerous indirect costs such as lost productivity due to outages and delays, failures and litigation. Thus, companies need to recognise the immediate need for anti-corrosion systems such as abrasive blasting and protective coatings.

Preventive strategies

Corrosion is a natural process but there are strategies to both prevent and manage it. Preventive strategies include:

* Increasing awareness of corrosion costs and potential cost savings
* Changing the misconception that nothing can be done about corrosion
* Establishing policies, regulations, standards and management practices to increase corrosion cost savings through effective corrosion management
* Improving education and training of personnel in the recognition of corrosion
* Implementing advanced design practices for improved corrosion management
* Improving corrosion technology through research, development and implementation

Corrosion appears in various types such as: galvanic, crevice and pitting corrosion, erosion corrosion, stress corrosion cracking, hydrogen damage and corrosion fatigue.

Rust prevention for each type of corrosion may differ in terms of design improvement, material selection, inhibitors, protective coatings and/or use of cathodic protection.

Addressing corrosion at the earliest stage improves the chances of preventing serious damage. Once areas of corrosion are identified, the application of protective coatings and cathodic protection are considered.

Cathodic protection

Cathodic protection is a corrosion prevention technique which involves making the target metal surface the cathode of an electrochemical cell. Another metal which serves as the anode of the electrochemical cell is “sacrificed” and undergoes corrosion, instead of the target metal surface. While cathodic protection may be used in marine environments, it is not effective in preventing micro-organism induced corrosion. A better alternative in many instances would be to apply protective coatings.

What are protective coatings?

Protective coatings are usually made of organic materials such as paint and plastic or rubber linings. Applied individually or in multiple layers, protective coatings prevent rust by acting as the barrier between the substrate and environmental elements. Rust prevention coatings have evolved into multi-purpose products providing not only superior corrosion control but also aesthetic surface appearance, abrasion and impact resistance and even electrical insulation. Effective selection and application of protective coatings require the vast experience and skills of a corrosion professional and adequate surface preparation.

Surface preparation

Surface preparation is a key step in many rust prevention practices. It involves the thorough removal of oxidation or rust, dirt, pre-existing protective coatings, residue, organic materials and other contaminants from the surface of a substrate. Surface preparation ensures the success of the selected protective coating for even the most advanced coating system will fail if surface preparation of the substrate is incorrect or incomplete. The goal of surface preparation is to remove all contaminants which could prevent adhesion of the selected coating and to promote a surface roughness for improved bonding with the protective coating. The performance of the protective coating will depend on the correct and thorough preparation of the surface prior to the application of the coating.

Abrasive blasting

Abrasive blasting is a type of surface preparation technique which involves forcibly propelling a stream of abrasive material such as sand, against a surface, for the purpose of creating a rough or smooth surface, reshape the surface or remove surface contaminants. Abrasive blasting may be dry or wet which utilises hot water to remove hazardous material in a safe manner.

Other types of surface preparation techniques include bead blasting (using fine glass beads propelled at high pressure) and hydro blasting (using highly pressured streams of water) to clean surfaces and remove paint, traces of corrosion and other contaminants with the least harm to the environment.

Rust prevention practices produce the best results when implemented as part of a continuing strategy. Companies in Mackay and the Bowen Basin mines must take a proactive approach by using protective coatings and adopting abrasive blasting or other adequate surface preparation technique. Corrosion control is a cost effective solution which can lead to substantial savings, and help ensure the safety of the community, the workplace and environment. Diamond Protective Coatings are the choice in engineered surface preparation and Corrosion Control Contractors. Contact Dennis Eagers for further information.

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