Who Discovered Yttrium? | Metal History

Yttrium is a silvery-metallic transition metal chemically similar to the lanthanides and has often been classified as a “rare-earth element“. Yttrium was discovered as early as the 18th century, but it has not been widely used until the last few decades in chemistry, physics, computer technology, film coating, medicine and other fields.

Yttrium History

In 1787, while the Swedish chemist Carl Axel Arrhenius exploring a quarry near Ytterby, a small town near Sweden’s capital city, Stockholm, he discovered an unusual black rock. He thought that he had discovered a new mineral, and sent some specimens to Johan Gadolin, a Finnish mineralogist, for analysis.

During the analysis, Gadolin isolated the yttrium from the mineral. The mineral was later named gadolinite in Gadolin’s honor, and Yttrium was named Ytterby from where the mineral was discovered.

In 1843, a Swedish chemist named Carl Gustaf Mosander studied yttrium samples and discovered three oxides, which were called yttria, erbia and terbia at that time. Currently, they are known as yttrium oxide (white), terbium oxide (yellow), and erbium oxide (rose-colored). A fourth oxide, ytterbium oxide, was identified in 1878.

Yttrium, a transition metal

In the Periodic Table of Elements, yttrium is considered one of the transition metals (yellow in the pic). Other more well-known transition metal elements include gold, silver and iron. The transition metals are the metallic elements that serve as a bridge, or transition, between the two sides of the table. They tend to be strong but pliable, therefore, some of these metals are widely used for wires. Yttrium wires and rods are used in electronics and solar energy. Yttrium is also used in lasers, ceramics, camera lenses, sputtering targets and dozens of other items.

Periodic Table
Periodic Table

Yttrium, a rare earth metal

Yttrium is also one of the seventeen rare-earth elements. The rare-earth elements include yttrium, scandium and 15 lanthanides. They have become indispensible in the manufacturing of cell phones and other technology. Despite their name, rare-earth elements are rather plentiful around the world. Yttrium can be found in most of the rare earth minerals, but has never been discovered in the Earth’s crust as a freestanding element.

Yttrium Properties

Atomic number 38
Atomic symbol Y
Atomic mass 88.906
Melting point 2,772 Fahrenheit (1,522 Celsius)
Boiling point 6,053 F (3,345 C)
Density 4.47 grams per cubic centimeter
State at room temperature Solid

Yttrium Applications

Yttrium metal is used as:

A deoxidizer for vanadium and other non-ferrous metals.

A nebulizer for nodular cast iron.

A catalyst for ethylene polymerization.

Added in small quantities to reduce the grain size in chromium, molybdenum, etc., as well as to strengthen aluminum and magnesium alloys.

Yttrium sputtering target for film coating.

Yttrium compounds have the following uses:

Yttrium oxide is used to produce yttrium iron garnets.

Yttrium oxide is used in ceramic and glass formulations.

Yttrium oxide is widely used for making compounds such as YVO4europium and YVO4europium phosphors in television tubes.

Yttrium iron (Y3Fe5O12), yttrium aluminium (Y3Al5O12) and yttrium gadolinium garnets possess interesting magnetic properties.

Yttrium iron garnets are extremely efficient transmitters and transducers of acoustic energy.

Yttrium aluminum garnet has a hardness of 8.5 and is finding application as a gemstone.

Yttrium oxide sputtering target is used for film coating.

Please visit https://www.sputtertargets.net/ for more information.

How was Chromium discovered? | Metal History

Chromium Discovery

In 1766, the German scientist Johann Gottlob Lehmann analyzed a Siberian ore and determined that it contained lead, which was classified as Siberian red lead.

Louis Nicolas Vauquelin
Louis Nicolas Vauquelin

 

In 1797, a bright red ore was found in the Siberian gold mine. The French chemist Louis Nicolas Vauquelin boiled the mineral with potassium carbonate, and got the lead carbonate and a yellow potassium salt solution of chromic acid. He added a high-mercury salt solution to the yellow solution, and a beautiful red solution appeared; the lead salt solution was added, and a yellowish precipitate appeared; when stannous chloride was added, the solution turned into a crisp green color. He thought that he had found a new metal, which was exactly chromium. The method produces metal chromium.

Chromium can produce beautiful multi-colored compounds: metallic chromium is silvery, chromium sulfate is green, magnesium chromate is yellow, potassium dichromate is orange, chromic is scarlet, and chromium oxide is green, chrome tanning is blue-violet, lead chromate is yellow…Thus Chromium got its name from the Greek word chroma, meaning color, and the chemical symbol is Cr.

Chromium Applications

Chromium was initially used as a pigment. At present, nearly all chromium is commercially extracted from chromite, also known as iron chromium oxide (FeCr2O4).

Chromium was considered to be a component of plants and animals in 1948. It was found to be biologically active in 1954. In 1957, chromium was identified as an essential trace element for animal nutrition. Chromium can act as an enhancer of insulin, affecting the metabolism of sugars, proteins, fats and nucleic acids through insulin.

As a metal element, chromium also has high industrial value. Chromium is widely used in metallurgy, chemical, cast iron, refractory and high-end technology industries.

Chromium sputtering target is an excellent film coating material applied for decorative coating, tool coating, semiconductor coating and so on.

Please visit https://www.sputtertargets.net/ for more information.

A Summary of the Titanium Alloy Properties

SAM®Titanium is a new type of metal. Its properties are related to the content of other impurities, such as carbon, nitrogen, hydrogen and oxygen. The purest titanium iodide has an impurity content of less than 0.1%, but it has low strength and high plasticity.

The general properties of 99.5% industrial pure titanium are as follow:

Stanford Advanced Materials
density ρ 4.5g/cm3
melting point 1725°C
thermal conductivity λ 15.24W/(mK)
tensile strength σb 539MPa
elongation δ 25%
section shrinkage ratio ψ 25%
elastic modulus E 1.078×105 MPa
hardness HB 195

(1) High specific strength

The density of titanium alloy is generally about 4.5g/cm3 (only 60% of steel), but the strength of pure titanium is close to that of normal steel. And some high-strength titanium alloys have higher strength than many alloy structural steels. Therefore, the specific strength (strength/density) of titanium alloy is much larger than that of other metal structural materials. It can be used to produce parts and components with high unit strength, good rigidity and lightweight. At present, titanium alloys are used for aircraft engine components, skeletons, skins, fasteners and landing gear.

Titanium Aeroplane Engine
Titanium Aeroplane Engine

(2) High-temperature strength

Titanium alloys can be used in higher temperature environments than aluminum alloys. Titanium alloys can retain the required strength and maintain long-term operation at the temperatures between 450 and 500 °C. While the specific strength of the aluminum alloy is significantly reduced when the temperature reaches 150 ° C.

(3) Good corrosion resistance

Titanium alloy can work in the moist atmosphere and seawater medium with good corrosion resistance, which is much better than stainless steel. It is especially resistant to pitting, acid etching and stress corrosion. In addition, titanium also has excellent corrosion resistance to alkali, chloride, chlorine organic substances, nitric acid, sulfuric acid, and the like. The fly in the ointment is that titanium has poor corrosion resistance to reducing oxygen and chromium salt media. For more information about the corrosion resistance of titanium, please read this passage Does titanium never corrode?

Titanium Ship
Titanium Ship

(4) Good low-temperature performance

Titanium alloys retain their mechanical properties at low and ultra-low temperatures. Titanium alloys with good low-temperature properties and extremely low interstitial elements. For instance, TA7 can retain a certain degree of plasticity at -253 °C. Therefore, the titanium alloy is also an important low-temperature structural material.

Please visit https://www.sputtertargets.net/ for more information.

The Self-Healing Ability of Cerium Coating (Chromium Substitute)

In recent years, several research efforts have targeted the utilization of rare earth elements, especially on cerium thin-film coatings. Cerium is a soft, ductile, and silvery-white metal that tarnishes when exposed to air, and it is so soft that can be cut with a knife. Cerium has no biological role and is not very toxic. Many surface treatments, like sol-gel, chemical vapor deposition (CVD) and physical vapor deposition (PVD) techniques, based on the use of cerium and cerium compounds have been investigated because of their low toxicity. In other words, consumption or inhalation of those compounds is not considered harmful to health.

Cerium compound physical vapor deposition permits improving corrosion protection performance of the surface on it is deposited on. The composition of the films has an impact on the corrosion properties of the cerium-based layer. In general, the coatings obtained by PVD are composed of Ce compounds in trivalent or tetravalent states. The ratio between these 2 oxidization states is strongly dependent on the oxidizing ability of the medium. However, no clear correlation between the Ce oxidation state and corrosion properties was found nowadays.

cerium film
cerium film

What’s more, these cerium coatings have an active mechanism similar to that observed for chromate coatings in that they both have the amazing self-healing ability when damage occurs. Chromate coatings have self-healing properties because of the presence of unreacted Cr6+ ions that are able to migrate to the exposed metal (for example a scratch) and can be further reduced to create a Cr3+ based compound that seals the scratch or the defect. However, the chromate compounds are extremely toxic and carcinogenic. Since cerium is not toxic, it is a perfect substitute for chromate. When it comes to cerium, the contact between a CeO2 film and solution induces the formation of Ce(OH)22+ ions. The existence of oxidizable metal would reduce these ions into Ce3+. Then the precipitation of trivalent cerium oxide occurs; it can be enhanced by the local increase of alkalinity. Therefore, this precipitated oxide seals the film and decreases the corrosion rate of the metal. Since cerium is not toxic, it is a perfect substitute for chromate.

In conclusion, cerium is good, but some people would concern about its price. Is rare earth element—Cerium—very expensive? The answer is not, actually Cerium is one of the least expensive rare earth and is the major component of “mischmetal”. So don’t care too much about the price.

For high purity sputtering targets & evaporation materials inquiries, please visit SAM Sputter Target.

For more news and knowledge about sputtering targets, please see SAM Target News.

Related Blog: How was cerium discovered? | History of Cerium

Molybdenum Target Mammography Detection

Breast cancer, one of the major causes of deaths among women, affects about 12% of women around the world. According to research surveys, the smaller the breast cancer is when it is detected, the less the possibility of death. This requires that women should go over the medical body check regularly to decrease the risk of breast cancer. At present, molybdenum target mammography is considered the recommended breast screening examinations for women’s breast cancer.

What is the Breast Cancer?

Breast cancer is caused by the development of malignant cells in the breast. It is a sign of breast cancer when cells in the breast begin to grow out of control, and these cells usually result in forming a tumor.

Breast Cancer
Breast Cancer

 

Breast cancer itself is not a fatal disease because the breast is not an indispensable organ for maintaining human life. However, if the malignant cells spread to other important parts of the human body, such as the heart, the liver, and kidney, breast cancer may lead to death.

Breast cancer occurs almost entirely in women, but men can get breast cancer, too. And it is closely related to age—only 5% of all breast cancers occurring in women under 40 years old.

What is Molybdenum target mammography?

Molybdenum target, or molybdenum sputtering target, is known as the materials in physical vapor deposition for film coating.

Molybdenum target mammography is another important application of Molybdenum target. It is a non-invasive method to test breast diseases such as breast mass and calcification. From the viewpoint of techniques, it is a digital imaging technology that combines traditional radiology technology with modern computer technology that transforms the X-ray image into a digital image that can be quantized. Molybdenum target mammography enables radiologists to find suspicious malignant lesions in mammography easier. Thus, it has been used as a routine examination to reduce the risk of breast cancer.

Molybdenum target mammography
Molybdenum Target Mammography

Why is Molybdenum target mammography beneficial?

Molybdenum target mammography is currently the primary choice for the diagnosis of breast disease. It is an easy and non-invasive method of examination which can accurately reflect the condition of the entire breast. What’s more, it can be used to observe the breast disease caused by various factors and the results are relatively reliable. With the help of Molybdenum inspection, some precancerous lesions can be found and can be followed up for observation. So it is beneficial for women’s health.

Above information is from SAM Sputter Target, a global sputtering targets manufacturer specialized in Molybdenum target.

How was Molybdenum discovered? | History of Molybdenum

The brief history of the discovery of molybdenum

Although molybdenum was discovered in the late 18th century, it was used early before its discovery. For example, in the 14th century, Japan used a molybdenum-containing steel to make a saber. In the 16th century, molybdenite was used as graphite because it was similar to the appearance and properties of lead, galena, and graphite. At that time, Europeans referred to these kinds of molybdenum-containing ore as “molybdenite”.

Bengt Andersson Qvist
Bengt Andersson Qvist

In 1754, the Swedish chemist Bengt Andersson Qvist tested the molybdenite and found that it did not contain lead, so he believed that molybdenite and galena were not the same substance.

In 1778, the Swedish chemist Carl Wilhelm Scheele found that nitric acid did not react with graphite. While nitric acid reacted with molybdenite and produced a white powder, which was boiled together with an alkali solution to crystallize a salt. He believes that this white powder is a kind of metal oxide. After heating with charcoal, no metal is obtained; and when it is heated together with sulfur, the original molybdenite is obtained, so he believes that molybdenite should be an unknown mineral.

Peter-Jacob-Hjelm
Peter Jacob Hjelm

Inspired by Scheler, in 1781, the Swedish chemist Peter Jacob Hjelm used a “carbon reduction method” to separate a new metal from the white powder and named the metal “Molybdenum”.

Molybdenum industry development

Since molybdenum is easily oxidized and has high brittleness, molybdenum smelting and processing are limited. Molybdenum was not able to be machined in the early period, so it is impossible to apply molybdenum to industrial production on a large scale. At that time, only a few molybdenum compounds were used.

In 1891, France’s Schneider Schneider took the lead in the production of molybdenum-containing armor plates using molybdenum as an alloying element. It was found to have superior properties, and the density of molybdenum was only half that of tungsten. Molybdenum gradually replaced tungsten as an alloying element of steel. The application of the molybdenum industry was started.

At the end of the 19th century, it was found that the properties of molybdenum steel were similar to those of tungsten steel of the same composition after the addition of molybdenum in steel. In 1900, the production process of ferromolybdenum was developed. The special properties of molybdenum steel to meet the needs of gun steel materials were also discovered. This made the production of molybdenum steel rapidly developed in 1910. Since then, molybdenum has become an important component of various structural steels that are resistant to heat and corrosion and has also become an important component of non-ferrous metals — nickel and chromium alloys.

This history column aims at introducing the history of different metal elements. If you are a metal lover or history lover, you can follow our website. For previous posts of metal history, you can look them up in the “history” category.

Please visit https://www.sputtertargets.net/ for more information.

How was cerium discovered? | History of Cerium

Cerium is the most abundant rare earth elements. It is a silvery gray active metal, whose powder is easily oxidized in the air and soluble in acid. Cerium has been widely used in the automotive industry as a catalyst to reduce emission, and in glass industry as glass polishing materials. Cerium sputtering target is an important material in optical coating.

Discovery History

In 1803, when the German chemist Martin Heinrich Klaproth analyzed an ore, he determined the existence of a new metal oxide and called it ochra (ocha-colored soil). and the ore ochroite because it appears to be ochre when burning.

In the same year, the Swedish chemist Jöns Jakob Berzelius and the Swedish mineralogist Wilhelm Hisinger also analyzed the same new metal oxide, which is different from yttrium. Yttrium is dissolved in ammonium carbonate solution and appears red when burning on gas flame. However, this metal oxide is insoluble in ammonium carbonate solution and does not exhibit characteristic flame color when burning.

The ore is thus called ceria (bauxite), and the element is named cerium to commemorate the discovery of an asteroid, Ceres.

Discovery of cerium

Three Early Applications of Cerium

Carl F. Auer von Welsbach
Carl Auer von Welsbach

Eighty-three years after the discovery of “cerium”, in 1886, the Austrian Carl Auer von Welsbach found the first application of cerium (also rare earth) as a luminescent enhancer for steam hoods. He found that heating 99% thorium oxide and 1% cerium oxide would give off a strong light, so cerium used in coal gas lamp gauze can greatly increase the brightness of the gas lamp. The gas lamps in Europe, where electric lights were not yet popular, were the main source of lighting and were essential for industrial production, commerce, and life.

After the First World War, electric lights gradually replaced gas lamps, but cerium continued to open up new applications. In 1903, Welsbach once again discovered the second largest use of cerium. He found that cerium iron alloys can generate sparks under mechanical friction and therefore can be used to make flints. This classic use of cerium has been around for 100 years. Everyone who smokes knows that a lighter uses a flintstone, but many people they that it is cerium that brings fire to people.

cerium arc carbon rods
cerium arc carbon rods

In 1910, the third important application of cerium was discovered for arc carbon rods in searchlights and film projectors. Similar to the steam cover, cerium can improve the efficiency of visible light conversion. Searchlights were once an important tool in war air defense. Arc carbon rods have also been an indispensable source of light for filming.

Modern Applications of Cerium

Since the 1930s, cerium oxide has been used as a glass decolorizer, clarifier, colorant, and abrasive polishing agent.

As a chemical decolorizer and clarifier, cerium oxide can replace the highly toxic white magnetic (oxidation) to reduce operational and environmental pollution.

The use of cerium titanium yellow pigment as a glass colorant produces a beautiful bright yellow art glass.

Cerium oxide as a main component to manufacture various specifications of polishing powder has completely replaced iron red polishing powder, greatly improving polishing efficiency and polishing quality.

As a glass additive, cerium can absorb ultraviolet light and infrared rays and thus has been widely used in automotive glass. It not only protects against UV rays but also reduces the temperature inside the car, thus saving air conditioning power.

cerium polishing powder
cerium polishing powder

This history column aims at introducing the history of different metal elements. If you are a metal lover or history lover, you can follow our website. For previous posts of metal history, you can look them up in the “history” category.

Please visit https://www.sputtertargets.net/ for more information.

Application of titanium and titanium alloys in medical field

Titanium is an ideal medical metal material and can be used as an implant for human body. Titanium alloy has been widely used in the medical field and has become the material of choice for medical products such as artificial joints, bone trauma, spinal orthopedic internal fixation systems, dental implants, artificial heart valves, interventional cardiovascular stents, and surgical instruments.

Application of titanium alloy in facial treatment

When the human face is severely damaged, local tissue repair should be treated by surgical implantation. Titanium alloy has good biocompatibility and required strength, so it is an ideal material for facial tissue repair. The skull bracket made of pure titanium mesh has been widely used in the reconstruction of the humerus and has achieved good clinical results.

titanium mesh
titanium mesh

Application of titanium in the pharmaceutical industry

SAM®Titanium is mainly used in the pharmaceutical industry for making containers, reactors, and heaters. Equipment used in the production of pharmaceuticals is often exposed to inorganic acids, organic acids, and salts, such as hydrochloric acid, nitric acid, and sulfuric acid. Therefore, these devices are easily damaged by long-term corrosion. On the other hand, steel equipment will introduce iron ions that affect product quality.

These problems can be solved with titanium equipment. For example, a penicillin esterification kettle, a saccharification tank, a chloramphenicol thin film evaporator, a dimethyl sulfate cooler, a chemical liquid filter, all have precedents for selecting a titanium material.

Application of titanium in medical devices

In the history of the development of surgical instruments, the first generation of surgical instruments was mostly made of carbon steel, which was eliminated because the performance of carbon steel instruments after electroplating did not meet the clinical requirements. The second generation is austenitic, ferritic and martensitic stainless steel surgical instruments. However, due to the toxicity of chromium in the stainless steel composition, the chrome-plated layer has a certain influence on the human body. Therefore, the third generation–titanium surgical instrument appeared.

titanium surgical blades
titanium surgical blades

The lightweight and high strength of titanium make it particularly suitable for microsurgery. Titanium has the advantages of corrosion resistance, good elasticity, and no deformation; even after repeated cleaning and disinfection, the surface quality of titanium is not affected; titanium is non-magnetic and does not pose a threat to tiny, sensitive implanted electronic devices. These advantages make the application of titanium surgical instruments more and more extensive. At present, titanium has been used to make surgical blades, hemostats, scissors, electric drills, tweezers and so on.

Application of titanium and titanium alloys in dentistry

Metals used in dental surgery began with amalgams and metal crowns in the 1920s. In the 1960s, gold, silver, and palladium alloys were mainly used. After the 1970s, stainless steel became the most commonly used material for permanent and detachable instruments for orthodontics. In the 1990s, titanium casting technology was promoted and applied.

titanium dental implant
titanium dental implant

Titanium has the characteristics of high dimensional accuracy, no bubbles, and shrinkage holes. Among the metal materials used for hard tissue repair in the human body, the elastic modulus of titanium is closest to human tissue, which can reduce the mechanical incompatibility between the metal implant and the bone tissue.

Please visit https://www.sputtertargets.net/ for more information.

Quick link to related titanium products:

Titanium (Ti) Sputtering Target

Planar Titanium (Ti) Sputtering Target

Rotatory Titanium (Ti) Sputtering Target

Short introduction to the element: Scandium

SAM®Scandium was first discovered by Lars Nilson in 1879. The origin of the name scandium comes from the Latin word ‘scandia’ meaning Scandinavia. It is a bright, silvery-white metal with active chemical properties that it easily oxidizes in air and reacts strongly with water. It has many of the characteristics of the rare earth elements, particularly yttrium.

In absolute terms, however, scandium is not rare. Scandium is abundant in minerals that it is found in concentrated amounts in the minerals euxenite, gadolinite and thortveitite; however, most of them existed as the form of scandium oxide (Sc2O3); thus due to the difficulties in the preparation of metallic scandium, global trade of the pure metal Scandium is very limited.

Scandium is usually alloyed with aluminum. Aluminum scandium alloys are used in the aerospace industry and other applications such as bicycle frames, fishing rods, golf iron shafts and baseball bats, etc. When used as an alloying element, adding a small amount of scandium to the aluminum alloy can promote grain refinement and increase the recrystallization temperature from 250 ° C to 280 ° C. Scandium is a strong grain refiner and an effective recrystallization inhibitor for aluminum alloys. It has a significant effect on the structure and properties of the alloy, and greatly improves the strength, hardness and corrosion resistance of the alloy.

Aluminum Scandium alloy

In addition to scandium alloys, garnets containing scandium are used as gain media in lasers, including those used in dental surgery, and scandium-stabilized zirconia has been recognized as a high-efficiency electrolyte in solid oxide fuel cells. Finally, scandium oxide is used in metal-halide lamps that are used to produce high-intensity white light that resembles sunlight.

Basic specification of scandium

Symbol: Sc
Atomic Number: 21
Atomic Weight: 44.95591
Color: silvery white
Other Names: Skandium, Skandij, Scandio
Melting Point: 1541 °C, 2806 °F, 1814 K
Boiling Point: 2836 °C, 5136 °F, 3109 K
Density: 2.985 g·cm3
Thermal Conductivity: 15.8 W·m-1·K-1

Please visit https://www.sputtertargets.net/ for more information about Scandium and other rare earth elements.

An overview of rare earth element

The content of rare earth elements in the earth’s crust is not that scarce as the name suggests. The total Clark value of rare earth is 234.51%, which is more than common elemental copper (Clarke value 10%), zinc (Clarke value 5%), tin (Clark value 4%) and cobalt (Clarke value is 3%). However…

Rare earth definition

Rare earth contains 17 metal elements of lanthanides as well as scandium and yttrium. Scandium and yttrium are included in rare earth element because they are often symbiotic with lanthanide elements in mineral deposits, thus have similar chemical properties.

rare earth element

Discovery of Yttrium

There are 250 kinds of rare earth minerals in nature. The first to discover rare earths element was the Finnish chemist John Gadolin, who separated the rare earth element yttrium (Y) from a bituminous heavy ore (Yttria, Y2O3) in 1794.

Origin of the name

There were few rare earth minerals discovered in the 18th century, and using  chemical methods can only a small amount of water-insoluble oxides could be produced. At that time, people often referred to water-insoluble solid oxides as earth. For example, aluminum was called “ceramic earth” and calcium oxide was called “alkaline earth”. At that time, rare earths are generally separated as oxides, and because of the small quantity, they were thus named Rare Earth (RE or R).

Rare earth is not rare

The content of rare earth elements in the earth’s crust is not that scarce as the name suggests. The total Clark value of rare earth is 234.51%, which is more than common elemental copper (Clarke value 10%), zinc (Clarke value 5%), tin (Clark value 4%) and cobalt (Clarke value is 3%). However, the distribution of rare earth elements is too scattered, and these seventeen elements always exist at the same time, so the total purity is not high. In general, minerals containing 10% rare earths can be called rare earth-rich ores; pure rare earth products are expensive due to their similar properties and difficulty in extraction.

Physicochemical property

  1. Lack of sulfides and sulfates, indicating that the rare earth elements have oxytropism;
  2. The silicate of rare earth is mainly island-shaped, without layered, frame-like and chain-like structures;
  3. Some rare earth minerals (especially complex oxides and silicates) exhibit an amorphous state;
  4. The rare earth minerals mainly include silicates and oxides in magmatic rocks and pegmatites, and fluorocarbonates and phosphates in hydrothermal deposits and weathering crust deposits;
  5. Rare earth elements are often symbiotic in the same mineral due to their similar atomic structure, chemical and crystal chemical properties. That is to say that the rare earth elements of the cerium and the yttrium are often present in one mineral. But these elements do not coexist in equal amounts– some minerals are mainly composed of cerium, and some minerals are mainly yttrium.

Please visit http://www.sputtering-targets.net/ for more information.