Borosilicate glass
Borosilicate glass is a type of
Borosilicate glass is sold under various trade names, including Borosil, Duran, Pyrex, Glassco, Supertek, Suprax, Simax, Bellco, Marinex (Brazil), BSA 60, BSC 51 (by NIPRO), Heatex, Endural, Schott, Refmex, Kimax, Gemstone Well, United Scientific, and MG (India).
Single-ended self-starting lamps are insulated with a mica disc and contained in a borosilicate glass gas discharge tube (arc tube) and a metal cap.[2][3] They include the sodium-vapor lamp that is commonly used in street lighting.[4][5][2][3]
Borosilicate glass melts at about 1,650 °C (3,000 °F; 1,920 K).
History
Borosilicate glass was first developed by German glassmaker
Manufacturing process
Borosilicate glass is created by combining and melting
In addition to
The manufacturing process depends on the product geometry and can be differentiated between different methods like floating, tube drawing, or molding.
Physical characteristics
The common type of borosilicate glass used for laboratory glassware has a very low thermal expansion coefficient (3.3 × 10−6 K−1),[7] about one-third that of ordinary soda–lime glass. This reduces material stresses caused by temperature gradients, which makes borosilicate a more suitable type of glass for certain applications (see below). Fused quartzware is even better in this respect (having one-fifteenth the thermal expansion of soda–lime glass); however, the difficulty of working with fused quartz makes quartzware much more expensive, and borosilicate glass is a low-cost compromise. While more resistant to thermal shock than other types of glass, borosilicate glass can still crack or shatter when subjected to rapid or uneven temperature variations.
Among the characteristic properties of this glass family are:
- Different borosilicate glasses cover a wide range of different thermal expansions, enabling direct seals with various metals and alloys like with a CTE around 5.0 because of the matched CTE with the sealing partner
- Allowing high maximum temperatures of typically about 500 °C (930 °F)
- Showing an extremely high chemical resistance in corrosive environments. Norm tests for example for acid resistance create extreme conditions and reveal very low impacts on glass
The softening point (temperature at which viscosity is approximately 107.6 poise) of type 7740 Pyrex is 820 °C (1,510 °F).[8]
Borosilicate glass is less dense (about 2.23 g/cm3) than typical soda–lime glass due to the low atomic mass of boron. Its mean specific heat capacity at constant pressure (20–100 °C) is 0.83 J/(g⋅K), roughly one fifth of water's.[9]
The temperature differential that borosilicate glass can withstand before fracturing is about 330 °F (180 °C), whereas soda–lime glass can withstand only about a 100 °F (55 °C) change in temperature. This is why typical kitchenware made from traditional soda–lime glass will shatter if a vessel containing boiling water is placed on ice, but Pyrex or other borosilicate laboratory glass will not.[1]
Optically, borosilicate glasses are crown glasses with low dispersion (Abbe numbers around 65) and relatively low refractive indices (1.51–1.54 across the visible range).
Families
For the purposes of classification, borosilicate glass can be roughly arranged in the following groups, according to their oxide composition (in mass fractions). Characteristic of borosilicate glasses is the presence of substantial amounts of silica (SiO2) and boric oxide (B2O3, >8%) as glass network formers. The amount of boric oxide affects the glass properties in a particular way. Apart from the highly resistant varieties (B2O3 up to a maximum of 13%), there are others that – due to the different way in which the boric oxide is incorporated into the structural network – have only low chemical resistance (B2O3 content over 15%).[10] Hence we differentiate between the following subtypes.
Non-alkaline-earth
The B2O3 content for borosilicate glass is typically 12–13% and the SiO2 content over 80%. High chemical durability and low thermal expansion (3.3 × 10−6 K−1) – the lowest of all commercial glasses for large-scale technical applications – make this a versatile glass material. High-grade borosilicate flat glasses are used in a wide variety of industries, mainly for technical applications that require either good thermal resistance, excellent chemical durability, or high light transmission in combination with a pristine surface quality. Other typical applications for different forms of borosilicate glass include glass tubing, glass piping, glass containers, etc. especially for the chemical industry.
Alkaline-earth
In addition to about 75% SiO2 and 8–12% B2O3, these glasses contain up to 5%
This is not to be confused with simple borosilicate glass-alumina composites.[12]
High-borate
Glasses containing 15–25% B2O3, 65–70% SiO2, and smaller amounts of alkalis and Al2O3 as additional components have low softening points and low thermal expansion. Sealability to metals in the expansion range of tungsten and molybdenum and high electrical insulation are their most important features. The increased B2O3 content reduces the chemical resistance; in this respect, high-borate borosilicate glasses differentiate widely from non-alkaline-earth and alkaline-earth borosilicate glasses. Among these are also borosilicate glasses that transmit UV light down to 180 nm, which combine the best of the borosilicate glass and the quartz world.[10]
Uses
Borosilicate glass has a wide variety of uses ranging from cookware to lab equipment, as well as a component of high-quality products such as implantable
Health and science
Virtually all modern laboratory glassware is made of borosilicate glass. It is widely used in this application due to its chemical and thermal resistance and good optical clarity, but the glass can react with sodium hydride upon heating to produce sodium borohydride, a common laboratory reducing agent. Fused quartz is also found in some laboratory equipment when its higher melting point and transmission of UV are required (e.g. for tube furnace liners and UV cuvettes), but the cost and manufacturing difficulties associated with fused quartz make it an impractical investment for the majority of laboratory equipment.
Additionally, borosilicate tubing is used as the feedstock for the production of
Borosilicate is widely used in implantable medical devices such as prosthetic eyes, artificial hip joints, bone cements, dental composite materials (white fillings)[13] and even in breast implants.
Many implantable devices benefit from the unique advantages of borosilicate glass encapsulation. Applications include veterinary tracking devices, neurostimulators for the treatment of epilepsy, implantable drug pumps, cochlear implants, and physiological sensors.[14]
Electronics
During the mid-20th century, borosilicate glass tubing was used to pipe coolants (often
Borosilicate glasses also have an application in the
bonded to the etched borosilicate glass.Cookware
Cookware is another common usage for borosilicate glass, including bakeware. It is used for some measuring cups, featuring screen printed markings providing graduated measurements. Borosilicate glass is sometimes used for high-quality beverage glassware, particularly in pieces designed for hot drinks. Items made of borosilicate glass can be thin yet durable, or thicker for extra strength, and are microwave- and dishwasher-safe.[15]
Lighting
Many high-quality flashlights use borosilicate glass for the lens. This increases
Several types of high-intensity discharge (HID) lamps, such as mercury-vapor and metal-halide lamps, use borosilicate glass as the outer envelope material.
New
Lighting manufacturers use borosilicate glass in some of their lenses.
Optics
Many astronomical reflecting telescopes use glass mirror components made of borosilicate glass because of its low coefficient of thermal expansion. This makes very precise optical surfaces possible that change very little with temperature, and matched glass mirror components that "track" across temperature changes and retain the optical system's characteristics.
The Hale Telescope's 200 inch mirror is made of borosilicate glass.[16]
The optical glass most often used for making instrument
Rapid prototyping
Borosilicate glass has become the material of choice for
Other
Aquarium heaters are sometimes made of borosilicate glass. Due to its high heat resistance, it can tolerate the significant temperature difference between the water and the nichrome heating element.[citation needed]
Specialty glass
Most premanufactured glass guitar slides are made of borosilicate glass.[citation needed]
Borosilicate is also a material of choice for evacuated-tube solar thermal technology because of its high strength and heat resistance.[citation needed]
The thermal insulation tiles on the Space Shuttle were coated with a borosilicate glass.[20]
Borosilicate glasses are used for immobilisation and disposal of radioactive wastes. In most countries high-level radioactive waste has been incorporated into alkali borosilicate or phosphate vitreous waste forms for many years; vitrification is an established technology.[21] Vitrification is a particularly attractive immobilization route because of the high chemical durability of the vitrified glass product. The chemical resistance of glass can allow it to remain in a corrosive environment for many thousands or even millions of years.
Borosilicate glass tubing is used in specialty
Trade names
Borosilicate glass is offered in slightly different compositions under different trade names:
- Borofloat of Schott AG, a borosilicate glass, which is produced to flat glass in a float process.
- Borosil, manufactured by the company of the same name, used in laboratory glassware and microwaveable kitchenware in India
- BK7 of Schott, a borosilicate glass with a high level of purity. Main use in lens and mirrors for laser, cameras and telescopes.
- Duran of DURAN Group, similar to Pyrex, Simax or Jenaer Glas.
- Pyrex borosilicate glass of Corning
- Fiolaxof Schott, mainly used for containers for pharmaceutical applications.
- Ilmabor of TGI (2014 insolvency), mainly used for containers and equipment in laboratories and medicine.
- Jenaer Glas of Zwiesel Kristallglas, formerly Schott AG. Mainly used for kitchenware.
- Kimax is the trademark for borosilicate glassware from Kimble
- United Scientific, manufacturers and distributors of laboratory glassware
- Rasotherm of VEB Jenaer Glaswerk Schott & Genossen, for technical glass
- Simax of Kavalierglass a.s., Czechia, produced for both laboratory and consumer markets.
- Supertek, manufacturer of scientific lab equipment and glassware.
- Willow Glass is an alkali free, thin and flexible borosilicate glass of Corning
- Boroux is a brand of borosilicate glass drinking bottles.
- Endural is a brand name of Holophane
Borosilicate nanoparticles
It was initially thought that borosilicate glass could not be formed into
In lampworking
Borosilicate (or "boro", as it is often called) is used extensively in the
In 1968, English metallurgist John Burton brought his hobby of hand-mixing metallic oxides into borosilicate glass to Los Angeles. Burton began a glass workshop at Pepperdine College, with instructor Margaret Youd. A few of the students in the classes, including Suellen Fowler, discovered that a specific combination of oxides made a glass that would shift from amber to purples and blues, depending on the heat and flame atmosphere. Fowler shared this combination with Paul Trautman, who formulated the first small-batch colored borosilicate recipes. He then founded Northstar Glassworks in the mid-1980s, the first factory devoted solely to producing colored borosilicate glass rods and tubes for use by artists in the flame. Trautman also developed the techniques and technology to make the small-batch colored boro that is used by a number of similar companies.[23]
Beadmaking
In recent years, with the resurgence of lampworking as a technique to make handmade glass beads, borosilicate has become a popular material in many glass artists' studios. Borosilicate for beadmaking comes in thin, pencil-like rods. Glass Alchemy, Trautman Art Glass, and Northstar are popular manufacturers, although there are other brands available. The metals used to color borosilicate glass, particularly silver, often create strikingly beautiful and unpredictable results when melted in an oxygen-gas torch flame. Because it is more shock-resistant and stronger than soft glass, borosilicate is particularly suited for pipe making, as well as sculpting figures and creating large beads. The tools used for making glass beads from borosilicate glass are the same as those used for making glass beads from soft glass.
References
- ^ a b Brandt, R. C.; Martens, R. I. (September 2012), "Shattering Glass Cookware", American Ceramics Society Bulletin, American Ceramics Society, archived from the original on 2015-03-10
- ^ a b "The Low Pressure Sodium Lamp".
- ^ a b "The Low Pressure Sodium Lamp".
- ^ "Lighting Comparison: LED vs High Pressure Sodium/Low Pressure Sodium". www.stouchlighting.com.
- ^ "The Sodium Lamp – How it works and history". edisontechcenter.org.
- ^ Spinosa, E. D.; Hooie, D. T.; Bennett, R. B. (1979). Summary Report on Emissions from the Glass Manufacturing Industry. Environmental Protection Agency, Office of Research and Development, [Office of Energy, Minerals, and Industry], Industrial Environmental Research Laboratory.
- ^ "Borosilicato". refmexgl.com. Archived from the original on 2012-06-30. Retrieved 2012-11-02.
- ISBN 978-0-12-475914-5.
- ^ "Borosilikatglas BOROFLOAT® – Thermische Produkteigenschaften". www.schott.com. Schott AG. Retrieved 31 August 2018.
- ^ a b "Technical glasses" (PDF). Archived (PDF) from the original on 2017-08-24. Retrieved 2017-08-24.
- doi:10.1039/B822285A.
- .
- ^ R Wananuruksawong et al 2011 IOP Conf. Ser.: Mater. Sci. Eng. 18 192010 doi:10.1088/1757-899X/18/19/192010 Fabrication of Silicon Nitride Dental Core Ceramics with Borosilicate Veneering material
- ^ "StackPath".
- ^ Estes, Adam Clark (March 16, 2019). "The Pyrex Glass Controversy That Just Won't Die". Gizmodo. Retrieved 2019-03-22.
- Bibcode:1988ESOC...30..281A. Retrieved 14 February 2021.
- ^ "Bor-crown glass from SCHOTT". Archived from the original on 2017-07-05.
- ^ Reynolds, Sheila (2018-02-15). "Material of the Month: Borosilicate". Swift Glass. Retrieved 2022-08-05.
- ^ "Safer Crack Cocaine Smoking Equipment Distribution: Comprehensive Best Practice Guidelines". www.catie.ca. Archived from the original on 2018-05-24. Retrieved 2018-05-14.
- ^ "SPACE SHUTTLE ORBITER SYSTEMS THERMAL PROTECTION SYSTEM". Archived from the original on 2009-07-15. Retrieved 2009-07-15.
- ^ M. I. Ojovan and W.E. Lee. An Introduction to Nuclear Waste Immobilisation, Elsevier, Amsterdam, 315 p. (2005)
- ^ Chemical & Engineering News Vol. 86 No. 37, 15 September 2008, "Making Borosilicate nanoparticles is now possible", p. 35
- ^ Robert Mickelsen, "Art Glass Lampworking History" Online Glass Museum, http://www.theglassmuseum.com/lampwork.html