Glass 101: Fused Silica vs. Quartz - Mo-Sci

Quartz, fused quartz, quartz glass, silica, fused silica&#; the list of terms used to describe various silica-based materials is long, confusing, and often misunderstood. In this article, we take a close look at the unique properties of quartz and fused silica (and a few related materials), and clear up the confusion surrounding these terms.

If you are looking for more details, kindly visit fused silica mirrors.

Quartz vs. Silica

The first important thing to know about quartz and fused silica is that they both primarily consist of the same ingredient: silica, also known as silicon dioxide. Silica has the chemical formula SiO2 and is the primary constituent of most types of glass. The main form in which silica is found in nature is the mineral quartz: a hard, transparent crystalline material that makes up an appreciable fraction of the Earth&#;s crust. While quartz primarily consists of silica, it also contains naturally occurring impurities in various proportions depending on its geological origin.

So, silica is a specific chemical compound, silicon dioxide, with the chemical formula SiO2. On the other hand, quartz is a naturally occurring crystalline mineral, which consists primarily of silica but contains some impurities.

Crystalline and Amorphous Solids

To fully understand the differences between different silica-based materials, we first need to review the fundamental differences between crystalline solids and amorphous solids.

The distinction comes down to how atoms are arranged inside the solids. In a crystalline solid, the constituent atoms are arranged in regular, repeating patterns known as crystal lattices. Quartz is an example of a crystalline silica-based material: silicon and oxygen atoms are arranged in a well-defined ordered structure.

However, in an amorphous solid, the atoms have no long-range order. The seemingly random arrangement of molecules in an amorphous solid resembles that of a liquid, except that they are fixed in place and don&#;t move around. Most materials that we think of as &#;glass&#; are amorphous solids: in fact, any material with an amorphous atomic structure can be described as &#;glassy&#;.  

Whether atoms are arranged in an orderly manner or oriented randomly can profoundly influence a material&#;s characteristics. One of the most striking examples is the glass transition effect exhibited by amorphous solids. Outside the world of silica or other oxide-based materials, disordered &#;glassy&#; metals are often used for their unusual mechanical characteristics compared to conventional metals.1

Silica-based materials &#; like quartz &#; can be characterized both in terms of their chemical composition and whether they are crystalline or amorphous.

Defining Silica-Based Materials

Now that we&#;ve reviewed some important fundamentals, we can define the differences between quartz, fused silica, and other silica-based materials.

Quartz

As mentioned previously, quartz is the main form in which silica occurs in nature. Quartz is a crystalline solid; so, while it can resemble glass both in terms of its appearance and its chemical makeup, it has very distinct properties from glass.

Industrial applications of quartz (that is, the crystalline mineral) are limited, but include quartz crystal oscillators in electronic systems &#; most familiarly in wristwatches.

Perhaps confusingly, &#;synthetic quartz&#; can be manufactured for industrial quartz applications. This would perhaps be better referred to as crystalline silica, but is often referred to simply as &#;quartz.&#;

Fused Silica and Fused Quartz

Here, the word &#;fused&#; refers to a processing step: fused silica is nominally pure silica that has been melted and cooled to form a glassy, amorphous solid. Fused silica resembles other glasses in many ways; but it does not contain any additives. Fused silica is a specialty material with a number of high-performance applications.

The terms &#;fused silica&#; and &#;fused quartz&#; are often used interchangeably. More accurately, &#;fused quartz&#; refers to an amorphous solid formed by melting naturally-occurring quartz. So, while fused silica is ostensibly pure SiO2, fused quartz contains impurities depending on the quartz that was used.

Silica Glass and Quartz Glass

These terms are typically used in a more generic sense, and can usually be considered interchangeable. Both of these terms could refer either to fused silica or fused quartz.

Applications of Fused Silica

While fused silica is chemically similar to quartz, its amorphous structure gives it a number of distinct and highly desirable thermal, mechanical and electrical properties.

Glasses commonly contain additives such as alkali, alkaline earth, or other oxides to lower the glass processing (melting) temperature and to improve chemical and physical properties &#; but fused silica is very pure. Consequently, it has higher working temperatures but offers different characteristics from other glasses.

Fused silica has a very low coefficient of thermal expansion, meaning it does not expand or contract much when heated or cooled. As a result, fused silica is highly resistant to thermal shock and can withstand very rapid heating or cooling without cracking. The thermal characteristics of fused silica make it highly valuable for high-temperature industrial components such as crucibles, trays, and boats for steelmaking and glass manufacture.2

Fused silica is transparent to a very wide spectrum of light, extending from deep ultraviolet to far-infrared. This makes it a key component in optical fibers, as well as in a range of lenses, mirrors, and other UV- or IR-transmitting optics.3,4

Contact us to discuss your requirements of Plano Concave Mirrors. Our experienced sales team can help you identify the options that best suit your needs.

Fused silica is also extremely chemically inert and resistant to most acids (with the notable exception of hydrofluoric acid). This chemical inertness lends fused silica to biomedical applications, often taking the form of porous silica.

The combination of thermal stability, transparency, and strength makes fused silica a strong candidate for new and developing applications such as photolithography substrates, etched microwave circuits, and as a protective layer in semiconductor devices.

Custom Glass Solutions from Mo-Sci

Mo-Sci develops and manufactures a range of high-performance glasses for technical applications. To find out more about our fused silica and porous silica products, or to discuss a custom glass application, get in touch with a member of our team today.

References and Further Reading

1. Glassy metal set to rival steel&#;: Nature News. https://www.nature.com/news///full/news..4.html.
2. Vert, T. Refractory Material Selection for Steelmaking. (John Wiley & Sons, ).
3. Khalaf, A. L., Shabaneh, A. A. A. & Yaacob, M. H. Carbon Nanotubes and Graphene Oxide Applications in Optochemical Sensors. in Synthesis, Technology and Applications of Carbon Nanomaterials 223&#;246 (Elsevier, ). doi:10./B978-0-12--2.-3.
4. Wang, S., Zhou, C., Zhang, Y. & Ru, H. Deep-etched high-density fused-silica transmission gratings with high efficiency at a wavelength of nm. Appl. Opt. 45, ().

According to Difference Between:

The key difference between fused silica and quartz is that fused silica contains non-crystalline silica glass whereas quartz contains crystalline silica.

Fused silica is also known as fused quartz. It is a glass containing almost pure silica in an amorphous form. Quartz, on the other hand, is a mineral compound containing silicon and oxygen atoms.

CONTENTS

1. Overview and Key Difference
2. What is Fused Silica
3. What is Quartz
4. Fused Silica vs Quartz in Tabular Form
5. Summary &#; Fused Silica vs Quartz

What is Fused Silica?
Fused silica, also known as fused quartz, is glass containing almost pure silica in the amorphous form. This type of glass is different from other available glasses on a commercial scale because the ingredients of the fused quartz production are different from others. These ingredients cause a change in the optical and physical properties of glass, including the lowering of melt temperature. Therefore, fused silica has a high working temperature, high melting temperature, etc. This also makes the glass less desirable for some common applications.

We can produce fused silica by fusing/melting high purity silica sand containing quartz crystals. The four common types of fused quartz in industries include type I, II, III, and IV.

Type I &#; produced by induction melting of natural quartz in the vacuum of inter atmospheres

Type II &#; produced by fusion of quartz crystal powder at a high flame temperature

Type III &#; produced by burning silicone tetrachloride in a hydrogen-oxygen flame

Type IV &#; produced by burning silicone tetrachloride in a water-vapour free plasma flame

What is Quartz?
Quartz is a mineral compound containing silicon and oxygen atoms. It contains silicon dioxide (SiO2) molecules. Moreover, it is the most abundant mineral on Earth&#;s crust. Though it contains SiO2, the repeating unit of this mineral is SiO4. This is because the chemical structure of quartz contains one silicon atom bonded to four oxygen atoms surrounding it. Hence, the geometry around on silicon atom is tetrahedral. However, one oxygen atom is shared between two tetrahedral structures. Therefore, the crystal system of the mineral is hexagonal.

Furthermore, quartz crystals are chiral. That means quartz exists in two forms as the normal α-quartz and the high-temperature β-quartz. The alpha form can transform into the beta form at around 573 °C. Looking at their appearances, some quartz types are colourless and transparent, while other forms are colourful and translucent. The most common colours of this mineral are white, grey, purple, and yellow.

What is the Difference Between Fused Silica and Quartz?
Fused silica or fused quartz is a glass containing almost pure silica in an amorphous form. Quartz is a mineral compound containing silicon and oxygen atoms. The key difference between fused silica and quartz is that fused silica contains non-crystalline silica glass whereas quartz contains crystalline silica. Moreover, fused silica is made by fusing/melting high purity silica sand containing quartz crystals, while quartz naturally occurs and it is industrially prepared by using &#;seed crystal&#; ( a small piece of carefully selected quartz) on which the quartz grow.

Summary &#; Fused Silica vs Quartz
Fused silica is also named as fused quartz, and it is a glass containing almost pure silica in the amorphous form. Quartz is a mineral compound containing silicon and oxygen atoms. The key difference between fused silica and quartz is that fused silica contains non-crystalline silica glass, whereas quartz contains crystalline silica.

Original Source

For more Plano Convex Mirrorsinformation, please contact us. We will provide professional answers.