New Test Method for Measurement of Decomposition Products in Phosphate Ester Fluids by Linear Sweep Voltammetry
1. Scope
1.1 This test method covers the voltammetric determination of alkylphenols in new or in-service phosphate ester fluids in concentrations from 100 ppm in new fluids up to higher concentrations found in in-service fluids by measuring the amount of current flow at a specified voltage in the produced voltammogram. 1.2 This test method can be used as a resource for a condition-monitoring program to track the hydrolysis or thermal degradation or both of the triaryl phosphate ester fluids. Alkylphenols, that is, weaker acids, are generated as a byproduct because of hydrolysis reactions or thermal degradation or both of the in-service fluid. This test method can help users with interpretation and troubleshooting results obtained using linear sweep voltammetry (LSV). 1.3 When used as part of fluid condition-monitoring practices, it is vital to apply trend analysis to monitor the hydrolysis or thermal degradation of the in-service fluid or assess the quality of the new fluid rate relative to a baseline standard reference fluid sample rather than use voltammetry for absolute measurement of the alkylphenol concentration. The trending pattern provides a proactive means to identify the level of fluid degradation or abnormal changes in the condition of the in-service lubricant. 1.4 Units--The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
The benefits of measuring alkylphenols are: monitor hydrolysis, monitor weaker acid, phosphate ester stability, and quality control of new/virgin fluids. The alkylphenols that are generated are contaminants and not antioxidants. The current standards listed below are for measuring aromatic phenols and aromatic amines antioxidants. New Standard Test method was proposed. Once that is done, it is recommended to make the necessary changes to D6224 so it can reference this standard.
