Fog composed of suspended particles of ice, partly ice crystals 20 to 100 microns in diameter but chiefly, especially when dense, droxtals 12 to 20 microns in diameter. It occurs at very low temper- atures, and usually in clear, calm weather in high latitudes. The sun is usually visible and may cause halo phenomena. Ic
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CUTTING WEAR
Comes about when hard surface asperities or hard particles that have embedded themselves into a soft surface and plough grooves into the opposing harder surface, e.g., a journal.
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ISO SOLID CONTAMINANT CODE (ISO 4406)
A code assigned on the basis of the number of particles per unit volume greater than 5 and 15 micrometers in size. Range numbers identify each increment in the particle population throughout the spectrum of levels.
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ADSORPTIVE FILTRATION
The attraction to, and retention of particles in, a filter medium by electrostatic forces, or by molecular attraction between the particles and the medium.
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AGGLOMERATE
The clustering together of a few or many particles into a larger solid mass.
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FATIGUE PLATELETS
Normal particles between 20 and 40 microns found in gear box and rolling element bearing oil samples observed by analytical ferrography. A sudden increase in the size and quantity of these particles indicates excessive wear.
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FILTRATION (BETA) RATIO
The ratio of the number of particles greater than a given size in the influent fluid to the number of particles greater than the same size in the effluent fluid.
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FATIGUE CHUNKS
Thick three-dimensional particles exceeding 50 microns indicating severe wear of gear teeth.
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BETA RATING
the method of comparing filter performance based on efficiency. This is done using the Multi-Pass Test which counts the number of particles of a given size before and after fluid passes through a filter.
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BETA-RATIO (ß-RATIO)
The ratio of the number of particles greater than a given size in the influent fluid to the number of particles greater than the same size in the effluent fluid, under specified test conditions (see 'Multi-Pass Test').
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FERROGRAPHY
An analytical method of assessing machine health by quantifying and examining ferrous wear particles suspended in the lubricant or hydraulic fluid.
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