Grease and Lubricant Testing

Depending on the conditions and the particular formulation, greases can actually promote corrosion, exactly contrary to the desired result. Several factors could be involved in grease-related corrosion.

1. Water soluble additives and water absorption.
2. Selection and use of corrosion inhibitors.
3. Separation of lubricant and thickener.
4. Grease degradation and production of acid and other water-soluble corrosive compounds.
5. Microbially-influenced corrosion (MIC) .
6. Generation of corrosive vapors and gases.
7. Thickness irregularities and lack of coverage.

Experience and testing indicates that corrosion of lubricated components can occur if the component steel or other metal becomes bare, or devoid of surface coverage by the lubricating grease or grease components. Water absorption and moisture penetration into a lubricated chamber may even lead to a corrosive condition on steel components, via moisture diffusion through the lubricating thin surface film layer. The use of corrosion inhibitors in grease may be of substantial benefit, but only if the inhibitor maintains its presence in a lubricating thin surface film or if it can act as a vapor phase corrosion inhibitor (VCI).

Separation of lubricant and thickener, with subsequent run-off of the lubricant, can create a condition where the lubricant and any corrosion inhibiting additives may also leave some susceptible metal unprotected, which could provide a site for corrosion in the presence of moisture.

A particularly serious corrosion problem may arise with the degradation of certain complex greases. Calcium acetate greases, for example, may hydrolyze and form a weak organic acid, during the degradation process. Weakly acidic vapors such as those generated through grease degradation  from acetic, formic, and other organic acids may interact and react with water on un-lubricated metal surfaces.

The risk of corrosion will be significantly reduced, if not completely eliminated, by ensuring that a complete and thorough grease layer with corrosion inhibitor is maintained on all component metal parts. Another step that may significantly reduce the potential for corrosion is to take all preventive steps to eliminate the ingress of moisture into the lubricated components and chamber.

The investigation of complex grease and lubricant failures may require multidisciplinary testing and analysis to determine the root cause of failure. The end determination must be made with a high degree of certainty to assure that proper replacement grease/lubricants are selected and that the most effective corrosion control methods are used.

At MATCO, we specialize in conducting corrosion testing and failure analysis investigations. This requires not only a laboratory that features state of the art equipment, but also a multidisciplinary professional staff . The Corrosion Testing and Product Development Laboratory, located in Pittsburgh , Pennsylvania , has been in existence since 1993 and is one of the premier corrosion testing and inspection facilities in North America. The four primary functions are:

• Lubricant and Grease Evaluation, Selection and Testing
• Laboratory and Field Evaluation
• Corrosion Protection Design, Inhibitors and Monitoring
• Materials Research and Development

The Corrosion Testing and Product Development Laboratory at MATCO boasts high tech instrumentation that includes computerized Electrochemical Corrosion Testing Equipment (AC And DC), Accelerated Corrosion Testing Equipment, Environmental (CF and SCC) Corrosion Testing Equipment, Alternate and Immersion Testing Equipment, Cabinet Testing and Mixed Flowing Gas testing equipment. Having the right tools is half the battle in providing accurate and reliable test results to the client.

The other half of the battle is having the right staff. At MATCO the Corrosion Division staff includes NACE (National Association of Corrosion Engineers) Certified Corrosion Engineers, Materials Selection/Design, Coatings and Cathodic Protection Specialists, Materials Scientists, Professional Engineers, Metallurgists, Polymer Scientists, Chemists, and Paint and Coating specialists. By combining the right equipment with the right staff, the root cause of problems can be determined.

MATCO's other capabilities include metallurgical investigations; R&D of new products or improvements to existing products, inspectors for onsite investigations and third party inspections, one to two day seminars on materials selection, corrosion, coating and failure analysis, and litigation support. We can also perform a wide array of routine NACE and ASTM test procedures for evaluating the corrosion resistance of metallic and non-metallic materials and components in adverse environments. If necessary, MATCO personnel can be on site within 48 hours when requested during emergency situations.

At MATCO, we provide you with a laboratory that you can count on. We deliver accurate and reliable test results and root cause determinations on which future materials selection and corrosion control decisions can be based.

WHO PERFORMS THE INVESTIGATIONS?:

Our team includes Certified Metallurgical/Corrosion / Cathodic Protection/ Materials Selection/ Design / Grease/ Lubricant/Coating Specialists and FEA specialists:

Dr. Zee                       Dr. Gibbon

Dr. Bayer                    Dr. Bavarian

Mr. Groll                     Mr. Gretz

Mr. Larkin                   Dr. Kasraie

Ms. Riley

Specialists in Corrosion Engineering & Failure Analysis:

Experienced PE, PhD Scientists, NACE Certified in Corrosion, Coating, Design , Materials Selection & Cathodic Protection Specialists who will solve your corrosion problems at both initial design stages and in service. We have been providing corrosion engineering services for over 3000 clients.

• Corrosion Engineering and Cathodic Protection of Production /Transmission Facilities: (a) Underground (b) Above Ground (c) Marine Environments
• Corrosion Evaluation, life expectancy determination and cathodic protection of electrical poles and transmission lattices
• Corrosion mapping, detection of "Hot Spots", cathodic protection of reinforced concrete structures
• Explosions/Fire Investigation forensic engineering
• Electrochemical EIS , DC and AC Testing - Determination of cathodic protection criteria for non-ferrous alloys and stainless steels
• On-site Evaluation of tanks and corrosion mitigation by protective coatings and internal or external Cathodic Protection
• Corrosivity determination of soil, water and determination of corrosion mitigation techniques
• On-site coating evaluation and selection of coatings for specific corrosive environments by EIS technique.

Corrosivity of Greases