ISSN:
0021-9304
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Medicine
,
Technology
Notes:
Low-copper amalgams aged at 37°C, 50°C, 60°C, 70°C, and 80°C for periods of 7 and 30 days were examined using a scanning electron microscope and an x-ray diffractometer. Gamma-one Ag-Hg grain size and γ2 Sn-Hg volume fraction, and surface area were determined by quantitative metallography. At 60°C and below, γ1 was the predominant matrix phase. Little β1 Ag-Hg was found. In this temperature range, both γ1 grain size and ADA creep were found to obey an Arrhenius law. A linear relationship was found between the log of the mean ADA creep and the mean γ1 grain size. Above 60°C, the γ1 phases and the majority of the γ Ag-Sn particles disappeared. In their place, β1 appeared. Gamma-two volume fraction increased during aging at temperatures over 60°C, but a coarsening of γ2, reflected in a decrease in γ2 surface area per unit volume, also took place. Aging for 30 days or less resulted in decreases in ADA creep. At 60°C and below, the decrease was caused by increases in γ1 grain size. Above 60°C, the decrease in ADA creep was caused by several factors, one of which was the appearance of large β1 grains.
Additional Material:
16 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jbm.820190611
Permalink
