US EPA

6673288 

Journal Article 

Fracture resistance of synthetic alpha-quartz seed plates 

Brownlow, DL 

1976 

23-31 

INSPEC:1044299 

Tests in an aqueous environment showed that water reduced the fracture strength 21%. Likewise, two organic solutions used in quartz cutting operations reduced the fracture strength of quartz but not to the same extent. Etching in hydrofluoric acid results in an initial reduction followed by a 20% increase. Etching in ammonium bifluoride at room temperature results in a 20% drop without any eventual recovery. However the fracture behavior resulting from etching at 50degC follows a pattern similar to that of the hydrofluoric acid solution. Optical microscopic examination of the surface texture corroborates the fracture data quite well. The fracture strength decreases with increasing temperature, but annealing at 550degC for 24 hours caused an increase. No indenter size effect was observed. A linear relationship of fracture load versus thickness of seed plates was obtained. A 24-hour gamma-ray irradiation produced no discernible changes in fracture strength.