Surface replication has been employed in engineering for many years, particularly for in situ high resolution metallography. Replicas can be made in any shape or size and, with suitable application methods, the high resolution can be achieved over the whole of the replica surface.

Replicas may be removed from surfaces with significant re-entrant detail, without damage, allowing the replication of fracture surfaces, spalling surface details, corrosion-pitting, cracks, surface mechanical damage, etc. The technique facilitates the detailed inspection of surface features at remote locations inside equipment, where access is difficult. Despite their flexibility when stretched, replicas retain their initial overall geometry and dimensions and are successfully employed both for high accuracy metrology applications, including surface finish and surface damage assessment, and for macroscopic measurements. When viewed microscopically under coaxial illumination, they have a bright metallic appearance, allowing detail such as microstructure, micro-cracking and pitting to be observed at high magnifications. These characteristics make the technique very suitable for the assessment of defects on critical engineering surfaces.

The benefits of being able to view remote defects microscopically and, where necessary, generate accurate dimensional and analytical information, makes replication a unique, versatile and powerful inspection tool.

A number of different inspection methods may be used to examine and assess replicas depending on the application, such as: macroscopy, optical microscopy and scanning electron microscopy (SEM).

Most replicating compounds have a resolution better than 0.1 microns and can be used not only for metallography but also for a multitude of other purposes including 3-D applications.

Cracks on the roll surface.

Roll surface.