月: 2023年1月

What Is Calcium Silicate?

Calcium silicate is a compound formed from calcium and silicate. It consists of more than 20 different compounds due to variations in the composition of its constituent elements. The most common types include ortho-calcium silicate, tricalcium silicate, and meta-calcium silicate, often referred to simply as calcium silicate.

This compound can be synthesized by reacting calcium oxide with silicon dioxide (from limestone and diatomaceous earth) at high temperatures. Calcium Silicate is safe for health and approved for use as a food additive.

Uses of Calcium Silicate

Calcium silicate serves as an effective building material, appreciated for its lightweight, thermal insulation, non-combustibility, and fire resistance. In agriculture, it finds extensive use as a fertilizer component.

In the ceramics industry, it prevents shrinkage, gas generation, and cracking when added during firing. It enhances the tensile strength, stiffness, and heat resistance of rubber and durability of paints as an additive. Additionally, it acts as an anti-caking agent in food products, such as baking powder and salt.

Properties of Calcium Silicate

Upon heating, calcium silicate hydrates release water, slowing the material’s temperature rise due to the heat of vaporization. It is noncombustible and has refractory properties.

Structure of Calcium Silicate

Calcium silicate, a type of silicate, comprises silicon dioxide, calcium oxide, and water in various ratios. Its microstructure features numerous voids, contributing to its lightweight, heat-retaining, and insulating properties.

Other Information on Calcium Silicate

Chemical Composition Variants of Calcium Silicate

Beyond the common types such as ortho-calcium silicate (Ca₂SiO₄), tricalcium silicate (Ca₃SiO₅), and meta-calcium silicate (CaSiO₃)n, numerous calcium silicate variants exist with varied chemical compositions.

Examples include 3CaO·SiO₂ (Ca₃SiO₅), 2CaO·SiO₂ (Ca₂SiO₄), 3CaO·2SiO₂ (Ca₃Si₂O₇), CaO·SiO₂, and CaSiO₃.

1. Ortho-Calcium Silicate
Ortho-calcium silicate, a major component of cement clinker (10-40%), is also known in the cement industry as dicalcium silicate or belite. Its chemical formula is Ca₂SiO₄, with a molecular weight of 172.24, consisting of tetrahedral SiO₄ structures.

2. Tricalcium Silicate
Tricalcium silicate, with the chemical formula Ca₃SiO₅ and a molecular weight of 228.32, contains tetrahedral SiO₄ and oxygen in its solid form. It is a primary component of cement clinker, comprising 40-70% of its makeup, and is referred to as tricalcium silicate in the cement industry.

3. Meta-Calcium Silicate
Meta-calcium silicate, or calcium metasilicate, has the formula (CaSiO₃)n and a molecular weight of 116.16 x n. It exists in two phases: the β-phase, known as wollastonite and stable at room temperature, with a density of 2.9 g/cm³, and the α-phase, known as pseudowollastonite.

What Is Temperature Compensated Crystal Oscillator (TCXO)?

TCXO is an oscillator with a temperature sensor and a temperature compensation circuit to minimize the frequency change due to changes in ambient temperature.

Uses of TCXOs

TCXOs are used in applications requiring frequency accuracy that cannot be achieved with a crystal oscillator or stable frequency accuracy over a wide temperature range.

Principle of TCXOs

A temperature sensor and circuits necessary for temperature compensation are added to the oscillation circuit to compensate for small changes in frequency caused by changes in ambient temperature. A crystal-based TCXO compensates the frequency by applying the voltage required for temperature compensation to a variable voltage capacitor such as a varicap, while MEMS-based TCXOs output temperature-compensated frequency with a decimal point PLL based on the information from a temperature sensor.

In addition to frequency stability, TCXO has other important specifications such as df/dT, vibration/shock resistance, and aging, which should also be considered when selecting components.

What Is Electromagnetic Interference Shielding?

Electromagnetic interference shielding refers to materials used to reduce or prevent electromagnetic interference. This concept is called noise control or EMC measures. Materials used as electromagnetic interference shielding are also called shielding materials.

Electromagnetic waves are generated by various devices in our daily life.

Cellular phones communicate through built-in antennas and base stations by emitting electromagnetic waves called radio waves. They use radio waves in the frequency range of 800 gigahertz to 2 gigahertz, known as microwaves.

Since electromagnetic waves exist in various wavelengths, they are generated when a plug is plugged into an outlet.

The material used to control such electromagnetic waves so that they do not interfere with each other is electromagnetic interference shielding.

Principle of Electromagnetic Interference Shielding

Electromagnetic interference shielding generally reduces the effects of electromagnetic waves by reflecting them. For example, there are two types of electromagnetic interference shielding methods for plastics: surface treatment and combined methods.

Surface treatment methods include the application of conductive paint (silver, nickel, copper) or plating (copper, nickel, chrome), vacuum deposition, sputtering, ion plating, and metal spraying.

Composite methods include glass and carbon fibers, metal fibers, metal flakes, and powders, which are a mechanism to obtain electrical conductivity and shielding properties by mixing conductive fillers with plastics.

In addition to reflecting electromagnetic waves, electromagnetic interference shielding can also be used to prevent electromagnetic waves by absorbing them. The methods are explained below.

How to Choose Electromagnetic Interference Shielding

What you need to know in selecting electromagnetic interference shielding are the composition and properties of electromagnetic waves.

Electromagnetic waves are broadly classified into radiation, light, radio waves, and electromagnetic fields, and are further divided into smaller categories.

For example, radiation is subdivided into gamma rays and X-rays. The frequencies and wavelengths of each are different and must be taken into consideration when selecting electromagnetic interference shielding.

From here, we will explain the less familiar electromagnetic field listed above.

Other Information on Electromagnetic Interference Shielding

1. How to Use Electromagnetic Interference Shielding

There are two types of electromagnetic interference shielding: electromagnetic shielding and magnetic shielding. Each is explained below.

Electromagnetic shielding: Prevents the intrusion or leakage of radio waves by enclosing the target space with conductive materials.

Magnetic Shield: Uses magnetic materials such as iron to seal the space, thereby bypassing magnetism and preventing its intrusion.

2. Absorption of Electromagnetic Waves

Electromagnetic interference shielding can absorb electromagnetic waves by allowing them to pass through their interior, thereby attenuating the energy of the electromagnetic waves.

3. Effectiveness of Electromagnetic Interference Shielding

Electromagnetic interference shielding is evaluated quantitatively using a numerical value called SE (Shielding Effectiveness).

4. About Electromagnetic Fields

Electromagnetic fields exist in power lines and household appliances. The term “electromagnetic field” refers to a phenomenon that combines electric and magnetic fields.

What Is a Test Facility?

A test facility is used to test the physical properties and characteristics of products and parts. Various tests are conducted depending on the industry, including performance tests, durability tests, and destructive tests.

The size of the facility varies based on the capacity required for testing. Some facilities occupy entire rooms for a single test, while others are large enough to conduct multiple tests simultaneously. There is a wide variety of test equipment, and specifications may change depending on the sample shape and required accuracy. Test equipment is often considered a fixed asset, with a determined useful life for each type.

Test Facility in Space Development

In space development, test facilities are crucial due to the harsh environment of vacuum, cryogenic temperatures, weightlessness, and high radiation. Durability tests are essential for space-related parts and facilities to prevent space debris and accidents. For example, thermal vacuum test facilities simulate the thermal environment of outer space and are used for testing.

EMC Test Facility

Electronic devices are tested for electromagnetic compatibility (EMC) in facilities like anechoic chambers. These chambers are designed to prevent external electromagnetic wave interference, leakage of waves, and internal wave reflection. They are crucial for testing products like antennas and wireless devices.

Exhibitions of Test Facilities

Test facilities vary across industries and are often tailored to specific test items, sample shapes, and other factors. Facilities like electron microscopes and nuclear magnetic resonance (NMR) machines are necessary for material and chemical testing.

Service Life of Test Facilities

Test facilities, often expensive and categorized as fixed assets, are subject to property tax and have a specified useful life. The useful life and depreciation expense differ for research and development assets compared to other uses. For example, buildings and facilities like anechoic chambers used in R&D have a useful life of 5 years, while instruments and fixtures have a life of 4 years. It’s important to consult with the local tax office for specific classifications and useful life determinations.

What Is Silver Oxide?

Silver oxide is a compound of oxygen and silver. Two types of silver oxide exist: silver oxide (I) and silver monoxide, with silver oxide (I) being commonly referred to as silver oxide. Silver oxide (I) is a dark brown powder obtained by adding a dilute solution of sodium hydroxide to a concentrated solution of silver nitrate.

Silver monoxide, on the other hand, is a grayish-black powder. It forms by the reaction of silver with ozone (O₃) and also by the reaction of aqueous silver nitrate with peroxodisulfate, (NH₄)₂S₂O₈.

Uses of Silver Oxide

1. Silver Oxide (I)

Silver (I) oxide finds wide application as catalysts, in the sterilization of drinking water, production of colored and conductive glass, glass polishing, hydroxy group introduction in organic synthesis, dehalogenating agent, and medical applications. Its strong bactericidal and deodorizing properties make it suitable for use in cosmetics.

2. Silver Monoxide

Silver monoxide serves various purposes including as oxidants and analytical reagents. It is also utilized in silver oxide-zinc alkaline batteries, which are small primary batteries using zinc as the anode, silver oxide as the cathode, and an alkaline solution as the electrolyte.

Properties of Silver Oxide

Silver oxide (I) is unstable to heat and light, decomposing into silver and oxygen upon exposure to sunlight or heat. It begins decomposing at approximately 160°C and rapidly decomposes at 250-300°C, releasing oxygen to form metallic silver. It completely decomposes at 300-340°C to form solid silver. Silver oxide (I) is insoluble in ethanol.

Silver monoxide is antimagnetic and decomposes into oxygen and silver at temperatures above 100℃. It is one of the strongest oxidizers and is insoluble in cold water but soluble in ammonia water.

Structure of Silver Oxide

1. Silver Oxide (I)

Silver oxide (I) has the chemical formula Ag₂O, a formula weight of 231.74, and a density of 7.14 g/cm³. Its crystal structure is cubic, similar to copper (I) oxide, with silver atoms arranged face-centered cubically and oxygen atoms arranged body-centered cubically.

2. Silver Monoxide

Although written with the formula AgO, silver monoxide is not an oxide of silver (II). According to X-ray diffraction results, it is believed to be a mixed oxide of silver (I) and silver (III), such as Ag^IAg^IIIO₂.

Other Information on Silver Oxide

1. Reaction of Silver (I) Oxide

Silver oxide (I) is slightly soluble in water, yielding the hydrolysis product Ag(OH₂)₂^–. It reacts with various acids and alkali chloride solutions, forming silver (I) chloride and alkali hydroxides. It also absorbs carbon dioxide in a wet state.

Silver oxide (I) dissolves in aqueous solutions containing ammonia (NH₃) and thiosulfate ion (S₂O₃^2-), forming complex ions such as silver diamine (I) ion ([Ag(NH₃)₂]⁺) and bis-thiosulfato silver (I) acid ion ([Ag(S₂O₃)₂]^3-), respectively.

2. Application of Silver (I) Oxide

Silver (I) oxide serves as a mild oxidant in organic chemistry and is used in the synthesis of carboxylic acids from aldehydes. It is often prepared in situ with alkali hydroxides and silver nitrate. Additionally, it is utilized in silver oxide batteries and as a substitute for silver powder in fine electronic circuit manufacturing.

What Is Lead Oxide?

Lead oxide is a yellow to reddish-yellow, odorless, powdery, inorganic compound. Composed of lead and oxygen, it has the chemical formula PbO, a molecular weight of 223.20, and CAS No. 1317-36-8. Other names include lead monoxide and lead (II) oxide. Its melting/freezing point is 888°C, and its boiling or first distillation point and boiling range are 1,470°C. It is almost insoluble in water and ethanol but soluble in nitric acid, acetic acid, and aqueous sodium hydroxide.

Structure of Lead Oxide

Lead oxide has two types of structures:

• α-type: red, tetragonal, and stable at room temperature (Mitsudasou or litharge).
• β-type: yellow, orthorhombic, and stable at temperatures above 300℃ (Kintsudasou or massicot).

The transition temperature to the β-type is 587°C, depending on the oxygen partial pressure.

Uses of Lead Oxide

1. Radiation Shielding Agent

Used in radiation protective clothing and shielding agents due to its radiation shielding properties, especially in medical fields where X-rays are used.

2. Pigments

Historically used as a pigment since ancient Roman times, lead oxide serves as an inorganic pigment, a raw material for paints, and a varnish for glass and ceramics.

3. Other Uses

Utilized as a raw material for vinyl chloride stabilizers, solid lubricants, synthetic rubber vulcanization accelerators, and electrode plates for lead-acid batteries.

Other Information on Lead Oxide

1. Production Methods

• Heating Metallic Lead: Lead can be oxidized to lead oxide at around 600°C, melted to lead oxide at around 1000°C, or sprayed with melted lead at 900°C or higher.
• Alkali Treatment: Lead nitrate mixed with ammonium carbonate or ammonium chloride in aqueous solution precipitates lead carbonate.
• Ore Refining: Produced as an intermediate product in the refining of lead ores into metallic lead.

2. Legal Information

Lead oxide is classified and regulated under various laws and regulations related to fire safety, poisonous and deleterious substances, safety and health, working environment evaluation, pollution control, and export.

3. Handling and Storage Precautions

Precautions include keeping containers tightly closed, storing in a cool, dark place, avoiding contact with incompatible materials, using only outdoors or in well-ventilated areas, and wearing protective gear when handling.

• Keep containers tightly closed and store in a cool, dark place.
• Store away from strong oxidizers, hydrogen peroxide, aluminum powder, and other incompatible materials.
• Use only outdoors or in well-ventilated areas.
• Take precautions to prevent dust dispersion.
• Wear protective gloves and glasses when using.
• After use, remove gloves appropriately to avoid skin contact with the product.
• Wash hands thoroughly after handling.
• In case of skin contact, wash with soap and plenty of water.
• In case of eye contact, rinse cautiously with water for several minutes.

What Is Iron Oxide?

Iron oxide is a compound formed by the chemical reaction of iron and oxygen, and is an important substance widely found in nature.

It is known to have different compositions, such as iron (II) oxide (FeO) and iron (III) oxide (Fe₂O₃), depending on the oxidation number. Both are iron oxides and, along with iron hydroxide, are components of rust.

Uses of Iron Oxide

Iron oxide is used in various fields because of its properties and characteristics.

1. Iron

Iron oxide is mined primarily in the form of red iron ore and magnetite. These iron oxides can be reduced at high temperatures to produce metallic iron, which is essential in the construction industry.

2. Magnetic Materials

Some iron oxides are magnetic and used as magnetic materials in compasses, speakers, motors, and recording media such as magnetic tapes and disks.

3. Pigments

Iron oxide comes in colors such as red, black, and yellow, making it useful as pigments and dyes in painting, printing, and dyeing applications.

4. Cosmetics and Pharmaceuticals

It is used in pharmaceuticals to treat anemia and in cosmetics such as lipsticks and blushes.

5. Medical Care

In the medical field, it serves as a contrast agent in nuclear magnetic resonance imaging.

Properties of Iron Oxide

Iron oxide exhibits various properties, with some characteristic ones listed below:

1. Color

Iron oxide compounds produce substances of different colors, including red, yellow, and black, making them valuable as pigments.

2. Magnetism

Magnetic iron oxides have strong magnetic properties, making them important for electronics and magnets.

3. Chemical Stability

Iron oxides are chemically stable and relatively resistant to acids and bases, making them suitable for various environments.

Types of Iron Oxide

Iron oxides are classified based on their oxidation number:

1. Iron (II) Oxide (FeO)

Also known as ferrous oxide, it is used in enamels, catalysts, and heat-absorbing glass.

2. Iron (III) Oxide (Fe₂O₃)

Also called ferric oxide, it is used as a pigment, abrasive, and raw material for magnetic tapes and magnets.

3. Iron (II, III) Oxide (Fe₃O₄)

Also known as magnetite, it is used for pigments, inks, and magnetic materials.

Other Information on Iron Oxide

Iron (III) Oxide Production Method

Iron oxide (III) is produced from iron sulfate (FeSO₄) obtained as a by-product from acid cleaning waste. It undergoes dehydration and decomposition processes to yield iron oxide particles.

FeSO₄・7H₂O → FeSO₄・H₂O + 6H₂O
   2FeSO₄・H₂O → Fe₂O₃ + SO₂ + SO₃ + 2H₂O

What Is Manganese Oxide?

Manganese oxide refers to compounds of oxygen and manganese that can exhibit various oxidation states.

Several types of manganese oxide are known, including MnO, Mn₃O₄, Mn₂O₃, MnO₂, and Mn₂O₇. These oxides display different properties based on their oxidation states; for example, MnO is a basic oxide with a low oxidation number, while Mn₂O₇ is an acidic oxide with a high oxidation number.

Manganese dioxide (MnO₂) is one of the most important types, commonly appearing as a blackish-brown powder. Upon heating, it releases oxygen to form manganese tetroxide, and with hydrochloric acid, it produces chlorine to yield manganese chloride.

Uses of Manganese Oxide

Manganese oxide is used in various applications:

1. Battery Industry

It is used as a cathode material in alkaline batteries and as a raw material for lithium manganate, a positive electrode material in lithium-ion batteries.

2. Industrial Applications

Manganese oxide serves as an oxidizing agent in the production of organic solvents due to its strong oxidizing properties. It is also used in the manufacturing of ferrite, a magnetic material, as well as in fireworks, matches, and for coloring glass.

Properties of Manganese Oxide

The properties vary depending on the type of manganese oxide:

1. Manganese Oxide (II) (MnO)

This green solid has a molecular weight of 70.93, a CAS number of 1344-43-0, and is insoluble in water. It is classified as a controlled substance under specified chemical regulations due to potential neurological effects.

2. Manganese Oxide (II, III) (Mn₃O₄)

This brown solid has a molecular weight of 228.79, a CAS number of 1317-35-7, and a melting point of 1705°C. It is almost insoluble in water.

3. Manganese Oxide (III) (Mn₂O₃)

This black solid has a molecular weight of 157.86, a CAS number of 1317-34-6, and a melting point of 1080°C. It is insoluble in water and may cause neurological and respiratory disorders.

4. Manganese Dioxide (MnO₂)

Appearing as a blackish-brown solid, manganese dioxide has a molecular weight of 86.94, a CAS number of 1313-13-9, and is virtually insoluble in water. It is known for catalyzing the decomposition of hydrogen peroxide into oxygen and water.

Types of Manganese Oxide

Manganese oxide is found in various minerals, including:

• Hausmannite (Mn₃O₄)
• Pyrolusite (β-MnO₂)
• Ramsdelite (γ-MnO₂)
• Manganite (MnO)
• Bixbyite (Mn₂O₃)

Structure of Manganese Oxide

The crystal structure of manganese dioxide (MnO₂) includes various types such as alpha, beta, gamma, delta, lambda, and type R (Ramsdelite).

Other Information on Manganese Oxide

1. Production Method

Manganese dioxide ore undergoes various processes such as crushing, reduction to manganese monoxide, dissolution in sulfuric acid, electrolysis, and precipitation to produce high-purity manganese solutions.

2. Manganese Oxide in Glass

The addition of manganese oxide imparts a purple color to glass compositions. It is typically included in the form of MnO₂ or Mn₂O₃.

What Is Magnesium Oxide?

Magnesium oxide (MgO) is a common alkaline earth metal oxide compound with various industrial and medicinal applications.

With a chemical formula of MgO, molar mass of 40.3 g/mol, density of 3.65 g/cm³, and CAS number 1309-48-4, magnesium oxide is widely utilized due to its versatile properties.

Uses of Magnesium Oxide

1. Medicines

Magnesium oxide serves as a traditional stomachic and laxative, effectively neutralizing acidic liquids to alleviate symptoms of gastritis and gastric ulcers. Its slow-acting nature and minimal carbon dioxide release make it a less irritating antacid compared to alternatives like sodium bicarbonate.

Administered in small doses, magnesium oxide exhibits significant efficacy, softening intestinal contents to act as a laxative. However, excessive intake may lead to hypermagnesemia, characterized by symptoms such as nausea, vomiting, and muscle weakness.

2. Industry

In various industrial applications, magnesium oxide is indispensable, serving as a raw material and additive for diverse products. Its thermal conductivity, insulation properties, acid resistance, and high-temperature resistance make it valuable in industries ranging from flue gas desulfurization to paint additives and ceramics manufacturing.

Recent attention has focused on its utility as a purifier of wastewater, soil conditioner, and fire-resistant material for emergency communication systems.

Properties of Magnesium Oxide

Magnesium oxide is virtually insoluble in water but soluble in acids, forming salts. Above 1,000°C, it becomes dense and insoluble in acids. It is also nearly insoluble in organic solvents and exhibits hygroscopic behavior, absorbing oxygen and water upon exposure to air.

Structure of Magnesium Oxide

At normal temperature and pressure, magnesium oxide exists as a hygroscopic white powder with a cubic crystal structure. Its light-reflecting properties find application in optical devices, while its fundamental properties are utilized in leather treatment.

Other Information on Magnesium Oxide

Magnesium Oxide Production Methods

Several methods exist for magnesium oxide production, including precipitation from seawater, burning of metallic magnesium, and heating or melting processes. Different processing conditions yield magnesium oxide variants with varying reactivity levels.

What Is Boron Oxide Powder?

Boron oxide, also known as boron trioxide (B₂O₃), is a colorless, non-crystalline, and hygroscopic compound containing boron and oxygen. Classified as a hazardous and toxic substance under the Industrial Safety and Health Law and the PRTR Law, boron oxide is commonly used in various industries.

Uses of Boron Oxide Powder

Boron oxide finds extensive application as a fluxing agent and cleaning agent in the production of specialty glasses, such as test tubes and optical glass. Its inclusion offers benefits like a lower melting point, enhanced heat resistance, mechanical strength, and improved resistance to water and chemicals. Additionally, it serves as a binder for ceramics when combined with boron nitride and is utilized as a catalyst in organic compound synthesis and refractory brick manufacturing.

Properties of Boron Oxide Powder

Boron oxide, with a molecular weight of 69.62 and CAS number 1303-86-2, melts at approximately 450°C and boils at about 1860°C. It exhibits a specific gravity of 2.46 for crystals and 1.8 for non-crystalline forms. Synthesized by dehydrating boric acid B(OH)₃, boric acid is derived from borax through treatment with sulfuric acid. Borax, known as sodium tetraborate (Na₂B₄O₇) decahydrate, serves as the precursor.

Other Information on Boron Oxide Powder

1. Boron Oxide as a Raw Material for Glass

Borosilicate Glass: Boron oxide and silicon dioxide combine to form borosilicate glasses, which are utilized as LCD panel substrate glass due to their alkali-free composition and inclusion of alumina (Al₂O₃).

Porous Glass: Porous glass production involves heat treatment of appropriately composed glass, primarily consisting of SiO₂-B₂O₃-Na₂O. Acid treatment separates the B₂O₃-Na₂O phase, resulting in porous glass with a SiO₂ backbone.

2. Synthesis of Boron-Based Non-Oxide Ceramics

Boron oxide facilitates the synthesis of boron-containing non-oxide ceramic powders, including boron carbide (B₄C), boron nitride (BN), and lanthanum hexaboride (LaB₆), through thermal carbon reduction. This solid-phase, endothermic reaction necessitates high temperatures.

3. Ores Containing Boron Oxide

Various ores contain boron oxide, including kernstone, coal ash boronite, colemanite, borate, borite, van derma stone, hydroborosite, kotoishi, dumbry stone, cyberiite, and ludwig stone. These ores can be processed to obtain boron oxide, crucial in multiple industrial applications.