Page 319 - Handbook of Materials Failure Analysis

316 CHAPTER 13 A concise filtergram wear particle atlas

50µm 50µm
(a) (b)
FIGURE 13.3
The two-body cutting wear particles (200 ): (a) a cutting wear particle from a gearbox in
cooling tower fans; (b) a cutting wear particle from a gas turbine/generator.

50µm 100µm
(a) (b)

FIGURE 13.4
The three-body cutting wear particles (200 ): (a) a cutting wear particle from a hydraulic
oil sample; (b) a cutting wear particle from a gearbox.

Figure 13.3 shows the typical two-body cutting wear particles from the oil samples
taken from different machines in a 400 Mw thermo-power plant.
The three-body cutting wear is produced by a foreign hard particle cutting on the
matching components. The morphology of the three-body cutting wear particles is
comparatively slim. Figure 13.4 shows the typical three-body cutting wear particles
from oil samples taken from different machines in a paper mill.

5 LAMINAR PARTICLES
Laminar particles are commonly found in the oil samples from rolling element bear-
ings and gearboxes. It is believed that laminar particles are formed by the rolling
press over the particles. The major features of laminar particles are a thin, flat sur-
face. Hence, laminar particles are easily distinguished by these features.