Donald R. Beaman

A method for preparing steel reinforced mortar or concrete for examination by transmitted light microscopy

Abstract This paper is intended for the petrographer or others who wish to study mortar or concrete and any associated details adjacent to a steel reinforcing bar (rebar) using transmitted light microscopy. Although the preparation of thin sections of mortar (or concrete) for petrographic examination has been a routine technique, the presence of reinforcing steel makes it difficult to obtain a satisfactory thin section. If it is important to study deposits such as corrosion products or any other details at the steel/mortar (concrete) interface, the selective removal of the majority of the steel greatly improves the possibility of obtaining thin sections. These thin sections not only allow for a petrographic examination of the mortar, but also allows for a petrographic examination of other materials at the steel/mortar interface.

Rapid Omnidirectional Compaction of Y 2 O 3 Stabilized Tetragonal Zirconia

The Rapid Omnidirectional Compaction (ROC) technique has been applied successfully to the densification of TZP (3 mole % yttria) ceramics at 1260°C. The combination of high pressure (830 MPa) and temperature results in the plastic deformation of the ceramic particles. The extent of deformation, and consequently, the ROCing temperature, can be determined by using hot hardness of the ceramic material as an approximation of the ceramics yield stress. The materials ROCed at 1260°C are characterized by a grain size of 0.15 gim, a flexure strength of 1300 MPa, a hardness of 1340 kg/mm 2 , and a fracture toughness of 5.0 MPa m 1/2 .

Thin-film coatings for flexible optical data storage

A write-once optical data storage media has been developed which is suitable for tape formats. The recording layer is a metal alloy system which is sputter deposited onto polymeric substrates as a single-layer thin film. The media are manufactured using a continuous sheet process, where the reflectivity of the film at 840nm can be selectively varied between 30 and 70%. These films have been characterized for laser write sensitivity, optical properties, surface chemistry, and environmental stability. An abrasion resistant hard overcoat is applied directly onto the active surface in a second vacuum deposition step. The media performance has been found to be compatible with direct hard-overcoats with no degradation in write sensitivity.