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336 MEMS and Microstructures in Aerospace Applications

TABLE 15.2
Various Environmental Pairs
High Temperature High Temperature and Low High Temperature and Solar
and Humidity Pressure Radiation

High temperature tends to Each of these environments This is a man-independent
increase the rate of moisture depends on the other. For combination that causes
penetration. High example, as pressure increasing effects on
temperatures increase the decreases, outgassing of organic materials.
general deterioration effects constituents of materials
of humidity. MEMS are increases; as temperature
particularly susceptible to increases, outgassing
deleterious effects of increases. Hence, each tends
humidity. to intensify the effects of
the other.

High Temperature and Shock High Temperature and High Temperature and
and Vibration Acceleration Explosive Atmosphere
Since both environments affect This combination produces the Temperature has minimal effect
common material properties, same effect as high on the ignition of an
they will intensify each temperature and shock and explosive atmosphere but
other’s effects. The degree to vibration. does affect the air–vapor
which the effect is intensified ratio, which is an important
depends on the magnitude consideration.
of each environment in
combination. Plastics and
polymers are more
susceptible to this
combination than metals,
unless extremely high
temperatures are involved.
Low Temperature and High Temperature and High Temperature and
Humidity Ozone Particulate
Relative humidity increases as Starting at about 3008F (1508C) The erosion rate of sand may be
temperature decreases, and temperature starts to reduce accelerated by high
lower temperature may ozone. Above about 5208F temperature. However, high
induce moisture (2708C), ozone cannot exist temperature reduces sand
condensation. If the at pressures normally and dust penetration.
temperature is low enough, encountered.
frost or ice may result.

Low Temperature and Low Temperature and Low Low Temperature and Sand
Solar Radiation Pressure and Dust
Low temperature tends to This combination can Low temperature increases dust
reduce the effects of solar accelerate leakage through penetration.
radiation and vice versa. seals, etc.

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