Metals

Wear Metals: Aluminum Cadmium Chrome Copper Iron Lead Molybdenum Nickel  Silver Titanium Tin

 

Additive Metals: Barium Boron Calcium Copper Magnesium Molybdenum Phosphorous Sodium

 

Contaminant Metals: Boron Potassium Silicon Sodium

Note that some metals fall into more than one of the headings listed.

Wear Metals
Normal and abnormal wear can be effectively traced by monitoring wear metal levels at each drain. It must be stressed that the effectiveness of diagnosing a critical situation is largely dependent on sampling frequency. This is to say that oil samples should be taken and analyzed at each drain. Routine sampling establishes base line values for each wear metal, and increases or decreases from these values give the analyst a clear picture as to which component is wearing out. For example, critical main and rod bearing wear is indicated by an increase in Lead content followed by a decrease in Lead and an increase in Copper and Tin content. This indicates that the soft Lead overlay of the bearing is worn off and the Copper babbitt material is exposed. If a sample history was not available to the analyst and only high Copper was noted, it would be impossible to tell whether the Copper was coming from a bearing, brushing, thrust washer, or oil cooler, all of which contain Copper.

 

Wear metal limits are established for specific lube systems by statistical analysis of similar systems. These limits are used in conjunction with trend analysis to provide the user with maintenance recommendations. Trend analysis is crucial when making accurate recommendations.  Each system establishes it's own base line wear levels depending on type of service, oil drain interval, operator technique, and many other variables. For this reason, the interpretation of wear metal analysis is best when based on a trend or history of that particular system.

 

Additive Metals
All quality lube oils are formulated with metal based additives that improve lubricant performance. They are blended into the oil at specific levels and change little during the usage period. Quantitative analysis of these metals serves as a quality control tool for maintenance personnel by assuring them that the oil formulation has not changed or the wrong oil has been added to the system.

 

Contaminant Metals
Contaminant metals are any metals that do not originate from oil chemistry or lube system wear. They include environmental debris (such as Silicon or Dirt), and additive metals from coolant (such as Sodium, Potassium and Boron). Obviously, these are not desirable elements to the lube system. Their presence in the oil indicates leaks in filtration or coolant systems.

 

Typical Metal Origins