Effect of Thermal Treatment on the Microstructure of Polycrystalline Silver Halide Fibers

The silver halide fibers were made by hot extrusion. The microstructure of the fibers changed after thermal treatment at different temperatures. SEM micrographs showed that the microstructure of the fibers did not change when temperatures of thermal treatment T 170℃, and their grain sizes were 1-2μm. The grain size grew up when T 170℃. The relation of grain size and T was as follows: 10-20μm, T = 200℃; 20-30μm, T = 250℃; 30～40μm, T = 300℃, respectively. The measurements of microhardness also showed that the microhaxdness of the fibers decreased as temperatures of thermal treatment increased when T 170℃ and the lowest microhardness appeared at 200℃.