User:Demxr2/Glass-ceramic

Adding/editing details, links, and references for existing introductory section below

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. When used for sealing, some glass-ceramics do not require brazing but can withstand brazing temperatures up to 700 °C. Glass-ceramics usually have between 30% [m/m] and 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, bioactivity, 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. In manufacturing, glass-ceramics are valued for having the strength of ceramic but the hermetic sealing properties of glass.

The paragraph above is already part of the article. I have added a few links to key terms and made minor changes to wording

Nucleation and Crystal Growth

The key to engineering a glass-ceramic material is controlling the nucleation and growth of crystals in the base glass. The amount of crystallinity will vary depending on the amount of nuclei present and the time and temperature at which the material is heated. It is important to understand the types of nucleation occurring in the material, whether it is homogeneous or heterogeneous.

Homogeneous nucleation is a process resulting from the inherent thermodynamic instability of a glassy material. When enough thermal energy is applied to the system, the metastable glassy phase begins to return to the lower-energy, crystalline state. The term "homogeneous" is used here because the formation of nuclei comes from the base glass without any second phases or surfaces promoting their formation.

Heterogeneous nucleation is a term used when a second phase or "nucleating agent" is introduced into the system. The presence of a second phase or surface can act as a catalyst for nucleation and is particularly effective if there is epitaxy between the nucleus and the substrate.

Glass-Ceramics in Medical Applications

Glass-ceramics are used in medical applications due to their unique interaction, or lack thereof, with human body tissue. Bioceramics are typically placed into the following groups based on their biocompatibility: biopassive (bioinert), bioactive, or resorbable ceramics.

Biopassive (bioinert) ceramics are, as the name suggests, characterized by the limited interaction the material has with the surrounding biological tissue. Historically, these were the "first generation" biomaterials used as replacements for missing or damaged tissues. One problem resulting from using inert biomaterials was the body's reaction to the foreign object; it was found that a phenomena known as "fibrous encapsulation" would occur, where tissues would grow around the implant in an attempt to isolate the object from the rest of the body. This occasionally caused a variety of problems such as necrosis or sequestration of the implant. Two commonly used bioinert materials are alumina (Al2O3) and zirconia (ZrO2).

SEM of two bone-forming osteoblasts on monetite crystals.

Bioactive materials have the ability to form bonds and interfaces with natural tissues. In the case of bone implants, two properties known as osteoconduction and osteoinduction play an important role in the success and longevity of the implant. Osteoconduction refers to a material's ability to permit bone growth on the surface and into the pores and channels of the material. Osteoinduction is a term used when a material stimulates existing cells to proliferate, causing new bone to grow independently of the implant. In general, the bioactivity of a material is a result of a chemical reaction, typically dissolution of the implanted material. Calcium phosphate ceramics and bioactive glasses are commonly used as bioactive materials as they exhibit this dissolution behavior when introduced to living body tissue. One engineering goal relating to these materials is that the dissolution rate of the implant be closely matched to the growth rate of new tissue, leading to a state of dynamic equilibrium.

Resorbable ceramics are similar to bioactive ceramics in their interaction with the body, but the main difference lies in the extent to which the dissolution occurs. Resorbable ceramics are intended to gradually dissolve entirely, all the while new tissue grows in its stead. The architecture of these materials has become quite complex, with foam-like scaffolds being introduced to maximize the interfacial area between the implant and body tissue. One issue that arises from using highly porous materials for bioactive/resorbable implants is the low mechanical strength, especially in load-bearing areas such as the bones in the legs. An example of a resorbable material that has seen some success is tricalcium phosphate (TCP), however, it too falls short in terms of mechanical strength when used in high-stress areas.

Relevant Literature:

Philosophical Transactions: Mathematical, Physical and Engineering Sciences , Mar. 15, 2003, Vol. 361, No. 1804, Nucleation Control (Mar. 15, 2003), pp. 575-589

El-Meliegy, Emad, and Richard Van Noort. Glasses and Glass Ceramics for Medical Applications. Vol. 9781461412281, Springer, 2012, pp. 6-17, 109-114

~~~~Demxr2~~~~

For developing the new History of Glass-ceramics Subsection

This is a recently added section by another contributor. I've been citing their additions, correcting linking issues, and adding relevant information from Industry pages to the History section.

Industry and Variations

Some well-known brands of glass-ceramics are Pyroceram, Ceran, Eurokera, Zerodur, Macor, Kedi, and Kanger. Nippon Electric Glass is a predominant worldwide manufacturer of glass ceramics, whose related products in this area include FireLite, and NeoCeram, ceramic glass materials for architectural and high temperature applications respectively. Keralite, manufactured by Vetrotech Saint-Gobain, is a specialty glass-ceramic fire and impact safety rated material for use in fire-rated applications. Glass-ceramics manufactured in the Soviet Union/Russia are known under the name Sitall. Macor is a white, odorless, porcelain-like glass ceramic material and was developed originally to minimize heat transfer during manned spaceflight by Corning Inc. StellaShine, launched in 2016 by Nippon Electric Glass Co., is a heat-resistant, glass-ceramic material with a thermal shock resistance of up to 800 degrees Celsius. This was developed as an addition to Nippon's line of heat-resistant cooking range plates along with materials like Neoceram. KangerTech is a ecigarette manufacturer which began in Shenzen, China which produces glass ceramic materials and other special hardened-glass applications like vaporizer modification tanks. TGP (Technical Glass Products), is a safety-oriented glass ceramic producer which continues to produce products like FireLite, fireframes, and the Pilkington Pyrostop.

The same class of material is also used in Visions and CorningWare glass-ceramic cookware, allowing it to be taken from the freezer directly to the stovetop or oven with no risk of thermal shock while maintaining the transparent look of glassware.

This is an entirely new section which is being developed as part of additions to the article

History

File:06Stookey-Obit-superJumbo.jpg

S. Donald Stookey

The discovery of glass-ceramics is credited to a man named S.Donald Stookey, a renowned glass scientist who worked at Corning Inc. for 47 years. ~~~~Demxr2~~~~ The first iteration stemmed from a glass material, Fotoform, which was also discovered by Stookey while he was searching for a photo-etch-able material to be used in television screens. Soon after the beginning of Fotoform, the first glass-ceramic material was discovered when Stookey overheated a Fotoform plate in a furnace at 900 degrees Celsius and found an opaque, milky-white plate inside the furnace rather than the molten mess that was expected. While examining the new material, which Stookey aptly named Fotoceram, he took note that it was much stronger than the Fotoform that it was created from as it survived a short fall onto concrete.

In the late 1950's two more glass-ceramic materials would be developed by Stookey, one found use as the radome in the nose cone of missiles, while the other led to the line of consumer kitchenware known as Corningware. Corning executives announced Stookey's discovery of the latter "new basic material" called Pyroceram which was touted as light, durable, capable of being an electrical insulator and yet thermally shock resistant. At the time, there wasn't many materials which offered the specific combination of characteristics that Pyroceram did and the material was rolled out as the Corningware kitchen line August 7th, 1958.

Some of the success that Pyroceram brought inspired Corning to put an effort towards strengthening glass which became an effort by the technical director's of Corning titled Project Muscle. A lesser known "ultrastrong" glass-ceramic material developed in 1962 called Chemcor (now known as Gorilla Glass) was produced by Corning's glass team due to the Project Muscle effort. Chemcor would even be used to innovate the Pyroceram line of productsas in 1961 Corning launched Centura Ware, a new line of Pyroceram that was lined with a glass laminate (invented by John MacDowell) and treated with the Chemcor process. Stookey continued to forge ahead in the discovery of the properties of glass-ceramics as he discovered how to make the material transparent in 1966. Though Corning wouldn't release a product with his new innovation, for fear of cannibalizing Pyrex sales, until the late 1970s under the name Visions.

FireLite, a transparent glass-ceramic material made for combined use with fire-rated doors and other safety materials, was launched in 1988 by Nippon Electric Glass. The glass ceramic at 5 mm thick is able to withstand the pressure of a fire hose after 20-90 minutes (depending upon the grade of ceramic used) of heat in a furnace, and still allows 88% of visible light to transmit through its surface. This product is still widely used and manufactured today by companies like TGP (Technical Glass Products), a fire-rated glass ceramic brand which is apart of the safety industry conglomerate Allegion.

~~~~Crook47~~~~

Peer Review By Racrz8 (talk) 16:44, 23 October 2020 (UTC)

• Things your draft does well
  • I appreciate the knowledge you guys have on the topic, ceramics are super cool
  • the expanding on nucleation is a good idea, this is a huge determinant of the stability of a material
  • I was impressed on the expanding of Stookey's accidental discovery, I only knew as much as Dr. Brow told us in glass which wasn't much
  • The medical applications section is a cool add, I know there’s a bunch of new developments in the biocompatibility of materials world
• Changes I Suggest
  • Maybe in your draft highlight which words links were added to? That way someone reviewing your contributions like I am would be able to see what you've added
  • consider expanding on the definition of a bioceramic. Is it a singular material or is that encompassing glass and composites? This could help the reader know exactly what sort of ceramics you're talking about (I'm sure you plan to do this but just in case :] )
  • When talking about pyroceram in the history part, remove the a before describing it’s properties. The a is unnecessary
    • Could maybe talk about the problems with new age corningware? How it isn’t made like it used to be and can shatter with the smallest of scratch that releases thermal shock (pretty sure I remember Dr. Brow talking about this in glass science but could be wrong)
  • In the history section: fotoform links to something different than what you’re talking about
• Things you could do to improve things
  • I think this is a wonderful start
  • great job linking to relevant pages and I hope my work on the bioactive glass page can help with yours

Great start! This is a wonderful topic and the medical use section could be super helpful to my page on bioactive glass.

Response to Peer Review by Crook47 and Demxr2

Crook47 Comment's

• Stookey's story was a particularly interesting find when I first dove into research for this page, so I'm glad you found it interesting. I have removed some of the grammatical and link errors that were specifically mentioned in your review.
• The specific mention of problems with new Corningware brand glass-ceramic materials were previously unknown to me, so I'm glad to be aware of that now. I plan to continue to look into expanding upon that in a blurb about recent history of glass-ceramics after further research into the depth of that topic as well as general history of the material from the late 80's until today.
• I plan to highlight changes that were written by myself as well to distinguish my additions from previously written work. Pictures and other diagrams will also be added to sections where applicable to further promote understanding of the material and expand upon available information.
• I recently found a nonfictional text about the history of Corning which I will continue to pick through for information on their developments of the glass-ceramic material specifically. Though I still am searching for relevant online and text sources that cover any meaningful changes over that period of time.

Demxr2 Comment's

• The first change suggested was to highlight the words that I added links to, so I made those bold to indicate that I added new links for those terms. Hopefully this will make it easier to see exactly what I added to that section.
• The second change suggested was to expand on the definition of bioceramic materials and I plan on doing this, I just haven't had the time to add more to that section yet. I intend to give a detailed description of compositions that are commonly used and the properties that these materials exhibit that allow for varying levels of bioactivity. These materials have significant implications for the medical field and since the article currently does not mention any sort of medical uses, I think it would be highly beneficial for me to focus on adding a lot of information related to this topic.
• Although our peer reviewer thinks it's a great start with good references, I think that I could still spend a fair amount of time finding more relevant literature to pull information from, especially for the medical usage of these materials.