Microscopic characterisation of black crusts on different substrates

Area of Science:

• * Building materials science
• * Environmental science
• * Geochemistry

Background:

• * Black crusts form on various urban substrates, impacting cultural heritage.
• * Understanding crust composition and substrate interaction is crucial for conservation.

Purpose of the Study:

• * To characterize black crusts on diverse substrates.
• * To investigate substrate-crust interactions and environmental influences.

Main Methods:

• * Microscopic analysis (stereo and scanning electron microscopy).
• * Compositional analysis (X-ray diffraction, Fourier transform infrared spectroscopy, energy dispersive X-ray spectroscopy).

Main Results:

• * Gypsum identified as the primary component in most black crusts, with calcite also present.
• * Substrate-specific interactions observed: diffuse boundaries on carbonate materials, defined on granite.
• * Environmental factors (pollution, marine influence, anthropogenic compounds) significantly influence crust development.

Conclusions:

• * Black crust formation is a complex process influenced by substrate type and environmental conditions.
• * The findings provide insights for developing effective conservation strategies for affected structures.