MMM Ceramic is not the better solution man! This material must be worked and tested to withstand high temperatures, it is not as reliable as the glass!
At this Moment i cant't buy any other Honeycomb glass screens because all sellers on Ebay and other don't ship in Italy, damn!
from italy!
OG California Style!
Do some more research while I have some more OG California Style!
Glass-ceramic
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Glass-ceramics are
polycrystalline materials produced through controlled crystallization of base glass. Glass-ceramic materials share many properties with both
glasses and
ceramics. Glass-ceramics have an amorphous phase and one or more crystalline phases and are produced by a so-called "controlled crystallization" in contrast to a spontaneous crystallization, which is usually not wanted in glass manufacturing. Glass-ceramics have the fabrication advantage of glass as well as special properties of ceramics. Glass-ceramics usually have between 30% [m/m] to 90% [m/m] crystallinity and yield an array of materials with interesting properties like zero porosity, high strength, toughness, translucency or opacity, pigmentation, opalescence, low or even negative thermal expansion, high temperature stability, fluorescence, machinability, ferromagnetism, resorbability or high chemical durability, biocompatibility, bio-activity, ion conductivity, superconductivity, isolation capabilities, low dielectric constant and loss, high resistivity and break down voltage. These properties can be tailored by controlling the base glass composition and by controlled heat treatment/crystallization of base glass.
Glass-ceramics are mostly produced in two steps: First, a glass is formed by a glass manufacturing process. The glass is cooled down and is then reheated in a second step. In this heat treatment the glass partly
crystallizes. In most cases nucleation agents are added to the base composition of the glass-ceramic. These nucleation agents aid and control the crystallization process. Because there is usually no pressing and sintering, glass-ceramics have, unlike sintered ceramics, no pores.
A wide variety of glass-ceramic systems exists, e.g., the Li2O x Al2O3 x nSiO2-System (LAS-System), the MgO x Al2O3 x nSiO2-System (MAS-System), the ZnO x Al2O3 x nSiO2-System (ZAS-System).
LAS System
The commercially most important system is the Li2O x Al2O3 x nSiO2-System (LAS-System). The LAS-system mainly refers to a mix of
lithium-,
silicon-, and
aluminum-
oxides with additional components e.g., glass-phase forming agents such as Na2O, K2O and CaO and refining agents. As nucleation agents most commonly zirconium(IV)-oxide in combination with titanium(IV)-oxide is used. This important system was studied first and intensively by Hummel,
[1] and Smoke.
[2]
After crystallization the dominant crystal-phase in this type of glass-ceramic is a high-quartz solid solution (HQ s.s.). If the glass-ceramic is subjected to a more intense heat treatment, this HQ s.s. transforms into a keatite-solid solution (K s.s., sometimes wrongly named as beta-
spodumene). This transition is non-reversible and reconstructive, which means bonds in the crystal-lattice are broken and new arranged. However, these two crystal phases show a very similar structure as Li could show.
[3]
The most interesting properties of these glass-ceramics are their thermomechanical properties. Glass-ceramic from the LAS-System is a mechanically strong material and can sustain repeated and quick temperature changes up to 800–1000 °C. The dominant crystalline phase of the LAS-glass-ceramics, HQ s.s., has a strong
negative coefficient of thermal expansion (CTE), keatite-solid solution as still a negative CTE but much higher than HQ s.s.. These negative CTE's of the crystal-phase contrasts with the positive CTE of the residual glass. Adjusting the proportion of these phases offers a wide range of possible CTE's in the finished composite. Mostly for today's applications a low or even zero CTE is desired. Also a negative CTE is possible, which means, in contrast to most materials when heated up, such a glass-ceramic contracts. At a certain point, generally between 60% [m/m] and 80% [m/m] crystallinity, the two coefficients balance such that the glass-ceramic as a whole has a thermal expansion coefficient that is very close to zero. Also, when an interface between material will be subject to thermal
fatigue, glass-ceramics can be adjusted to match the coefficient of the material they will be bonded to.
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