83
2
Contemporary
Methods of Protection
and Restoration of
Components
From the very moment a material is released from the point of production, it is
subjected to some form of material degradation and no known service environment
provides perfect immunity to this process (Batchelor et al., 2011). Almost any known
natural phenomenon contributes to damage mechanisms that cause premature failure of components and devices. Forms of materials degradation can be classified as
physical, chemical, or biological phenomena which usually occur in combinations,
as illustrated in Figure 2.1.
Batchelor et al. (2011) emphasize that normally multi-phenomena modes of damage take place and protective measures are ineffective when a single-phenomenon
mode of damage is mistakenly assumed. Among examples of interactions between
degradation processes, the authors named corrosive-wear, which is mechanical wear
accelerated by chemical damage to a worn material (physicochemical phenomena).
Biochemical phenomena occur, e.g., when not only organisms themselves eat artificial materials, but also waste products of bacteria are destructive to materials. If
a metal component is implanted in the human body, it is a subject of biological,
chemical, and physical phenomena imposing severe stresses and accelerated materials degradation.
Under the influence of various degradation factors, an adequately protected material can retain its characteristics longer, as shown in Figure 2.2. Nevertheless, even
the best protection is unable to prevent a component from degradation and subsequent failure. The restoration process can be applied either before the component
reaches the critical level or after a failure, and its functional characteristics may be
restored below or above the initial performance level.
Besides prevention from degradation, some other important properties of solid
surfaces can be enhanced (Martin, 2011):
• Wear resistance
• Hardness
• Lubricity
• Corrosion and chemical resistance
• Optical properties (transmittance, reflectance, emittance)
DOI: 10.1201/9781003218654-2
2
Contemporary
Methods of Protection
and Restoration of
Components
From the very moment a material is released from the point of production, it is
subjected to some form of material degradation and no known service environment
provides perfect immunity to this process (Batchelor et al., 2011). Almost any known
natural phenomenon contributes to damage mechanisms that cause premature failure of components and devices. Forms of materials degradation can be classified as
physical, chemical, or biological phenomena which usually occur in combinations,
as illustrated in Figure 2.1.
Batchelor et al. (2011) emphasize that normally multi-phenomena modes of damage take place and protective measures are ineffective when a single-phenomenon
mode of damage is mistakenly assumed. Among examples of interactions between
degradation processes, the authors named corrosive-wear, which is mechanical wear
accelerated by chemical damage to a worn material (physicochemical phenomena).
Biochemical phenomena occur, e.g., when not only organisms themselves eat artificial materials, but also waste products of bacteria are destructive to materials. If
a metal component is implanted in the human body, it is a subject of biological,
chemical, and physical phenomena imposing severe stresses and accelerated materials degradation.
Under the influence of various degradation factors, an adequately protected material can retain its characteristics longer, as shown in Figure 2.2. Nevertheless, even
the best protection is unable to prevent a component from degradation and subsequent failure. The restoration process can be applied either before the component
reaches the critical level or after a failure, and its functional characteristics may be
restored below or above the initial performance level.
Besides prevention from degradation, some other important properties of solid
surfaces can be enhanced (Martin, 2011):
• Wear resistance
• Hardness
• Lubricity
• Corrosion and chemical resistance
• Optical properties (transmittance, reflectance, emittance)
DOI: 10.1201/9781003218654-2