| Popis: |
Gaseous acid treatment (HBr) of surface-hardened binary glass microballoons results in etching and the growth of salt nodules, tubes or whiskers, depending on moisture conditions. Temperatures from 400/sup 0/C to 625/sup 0/C for 24 h or more are required for the effects to be significant. Numerous imperfections, including craters, are documented on the unexposed interiors surfaces. The evident phase separation and nucleation sites suggest a need for better production controls and post-production annealing. 6 figures. |
