Accuracy of mercury-alloy proportioning systems.
To measure the reproducible accuracy of some commercially available mercury/alloy proportioning systems, a study was made of several mercury dispensers, alloy pellets, and disposable capsules. This study included a consideration of some human variables that were introduced in manipulating the systems. Most of the systems that were tested provided acceptable accuracy when used correctly.
Factors influencing the marginal adaptation of amalgam.
Results of this study indicated that under controlled technics the best adaptations were obtained by using small increments of 50 to 52 percent mercury amalgam mix without expressing mercury, and by use of lateral condensing thrusts.
Phase formation during mechanical alloying in the Ti–Si system
Abstract Mechanical alloying of Ti–Si powder mixture or TiH 1.924 –Si powder mixture was performed by high-energy ball milling, in which the Ti to Si mole ratio was 1:2. The phase formations in both mixtures during milling were investigated by X-ray diffraction. Mechanical alloying a mixture of elemental powders led to the formation of TiSi 2 equilibrium compound, while when starting from Si + TiH 1.924 , a metastable phase was formed. The metastable phase completely transforms to TiSi 2 when the mechanically alloyed powder is annealed at temperatures above 800 °C. Two different pathways of phase transitions during mechanical alloying are attributed to the existence of hydrogen atoms, i.e., when starting from Si + TiH 1.924 compared to Si + Ti, the kinetics for the formation of the TiSi 2 intermetallic compound slows down. The kinetics related to the different phase transitions depending on the starting powder mixture are discussed.