Fine Structure of Metallic Surfaces with the Electron Microscope

Abstract

Several techniques for producing surface replicas to be used in the transmission electron microscope are briefly discussed and compared on the basis of experience with them in this laboratory. A new two‐step replica process is described which utilizes molded polystyrene as the first replica and evaporated silica as the second, thin film replica. The high mobility of condensing silica vapor on polystyrene is pointed out and it is shown that such evaporated films tend to fill in small surface irregularities and so produce a replica of fine surface structure which appears to be reliable. A table is included which gives an idea of the amounts of silica required for several surfaces of different ``roughness'' to yield films that are of about the same quality for use in the electron microscope. Electron micrographs of replicas so prepared are exhibited illustrating some pearlitic structures in a 0.98 C, hot roll steel, precipitation in a Cu–Be alloy, and a calcite cleavage plane. Excellent resolution can be obtained in such replicas and a resolution of approximately 50A is demonstrated in the calcite cleavage plane.