A Study on the Chemical Durability of Devitroceramics -Dissolution Phenomena of Devitrocermics into Acids-

Glass-Ceramics and Photo-Sitalls

“…The former are apparently due to the remains of the crystalline phase, which is most stable with respect to these acids (such as {3-quartz or lithium disilicate), whereas the latter are due to traces of the glassy phase, which is least stable and dissolves in the acid, leaving behind the depression. Such a corrosion mechanism for photosensitive glassceramic, starting with the leaching away of the chemically least stable glassy phase surrounding the tiny crystal grains, agrees well with the literature data for glass-ceramics [589][590][591]7641.…”

“…The same authors [591] studied the chemical stability to acid and basic solutions of glass-ceramics and glasses of the composition Li 2 0 . Al 2 0 3 • 3Si0 2 and of mica-spodumene composition.…”

“…The dependence between the weight losses a and the solution time was [CH. V [591]: an = kT, where n = 2 for mica-spodumene glass-ceramic, and n = 1 for glass of the mica-spodumene system, as well as for glass and glass-ceramic of the Li 2 0 • Al 2 0 3 • 3Si0 2 composition. More complex dependencies were observed by dissolving the glassceramic Li 2 0 • Al 2 0 3 • 3Si0 2 in a 4.4 N solution of NaOH at 88°C, due to the additional flakes going over into the solution.…”

“…In addition to the works mentioned above, a very limited number of publications appeared in the literature dealing with the chemical stability of glass-ceramics [768][769][770][771][772][773]. There are no data in the literature on the chemical stability of photosensitive glass- ceramics.…”