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

In recent years, several research efforts are targeted on 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 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) technique, 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 to improve corrosion protection performance of the surface 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 compound in trivalent or tetravalent states. The ratio between these 2 oxidization states is strongly depending 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 that they both have the amazing self-healing ability when damage occurs. Chromate coatings have the 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 metal. Since cerium is not toxic, it is a perfect substitute for chromate.

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

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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.

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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.

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Quick link to related titanium products:

Titanium (Ti) Sputtering Target

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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.

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How was tantalum discovered? | History of Tantalum

In the middle of the 17th century, a very heavy black mineral (density of SAM®Tantalum is 16.68 g/cm3) found in North America was sent to the British Museum for safekeeping. After about 150 years, in 1801, British chemist Charles Hatchett accepted the ore analysis task from the British Museum. He discovered a new element and named it Columbium (later renamed Niobium) to in honor of the place where the mineral was first discovered – Colombia.

Tantalum

In 1802, when the Swedish chemist Anders Gustaf Ekberg analyzed their minerals (the niobium-tantalum ore) in Scandinavia, he discovered a new element. He named it Tantalum, referring to the name of Tantalus, the son of Zeus God in Greek mythology.

Because Niobium and Tantalum are very similar properties, they were once thought to be the same element. In 1809, the British chemist William Hyde Wollaston compared the Niobium oxide and Tantalum oxide. Although they gave different density values, he still believed that the two were identical substances.

Tantalum Discovery History

By 1844, the German chemist Heinrich Rose refuted the conclusion that Niobium and Tantalum were the same elements, and proved that they are two different elements through chemical experiment. He named the two elements “Niobium” and “Pelopium” in the name of the Greek mythology of Tantalus’s daughter Niobe (the goddess of tears) and the son of Pelops.

In 1864, Christian Wilhelm Blomstrand, Henry Edin St. Clair Deville and Louis Joseph Troost clearly proved the Tantalum and Niobium are two different chemical elements ,and determined the chemical formula of some related compounds. In the same year, Demarinia heated tantalum chloride in a hydrogen atmosphere, and got tantalum metal for the first time through a reduction reaction. Early tantalum metals contain many impurities, and it was not until 1903 that Werner von Bolton first made pure tantalum metal.

This is a history column of SAM Sputter Target, aiming at introducing the history of different metals. If you are a metal lover or history lover, you can follow our website. For previous posts of metal history, you can search the keyword “history”.

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How was aluminum discovered?| History of Aluminum

AluminumDiscovery

Humphry Davy
Humphry Davy

Compared with other metal elements we discussed about before, Aluminum is discovered much later. In 1808, the British chemist Sir Humphry Davy confirmed the existence of alum and named the substance to Alumium (later changed to Aluminum).

In 1825, Danish chemist and physicist Hans Christian Ørsted began experimenting about aluminum extraction. However, it was not until 1827 that Friedrich Wöhler reduced the molten anhydrous aluminum chloride with potassium metal to obtain a purer metallic aluminum element.

As precious as gold

However, as Wöhler’s method could not yield great quantities of aluminium, the metal remained rare; its cost exceeded that of gold. It is for this reason that aluminum was in a high position at that time. It is said that at a banquet, the French emperor Napoleon used aluminum knives and forks alone, while others used silver tableware. Also, the king of Thailand once used an aluminum bracelet.

Mass production

Charles Martin Hall
Charles Martin Hall

In 1886, French engineer Paul Héroult and American engineer Charles Martin Hall, respectively, independently electrolyzed a mixture of molten bauxite and cryolite to produce metal aluminum, which laid the foundation for large-scale production of aluminum in the future. Since then, the status of aluminum has changed completely, mainly in two aspects: first, it is mass-produced and is no longer regarded as a precious metal; the mass production of aluminum in industrial and domestic applications has gradually replaced the use of other metals such as steel and copper in many fields.

Application Prospect

At present, the aluminum industry has problems such as overcapacity and insufficient utilization, so the development prospects of the aluminum industry in the short term are not optimistic.

However, due to the abundant reserves of aluminum in the earth’s crust and the advantages over other metal elements, aluminum will have extremely broad application prospects in the future. For example, automakers are currently exploring the use of large-area aluminum alloy instead of steel to make the car lighter.

With the advancement of technology, aluminum alloy products will not only grow rapidly in traditional applications such as aerospace, transportation, electronic power, and construction, but will also grow rapidly in other new fields.

 

This is a history column of SAM Sputter Target, aiming at introducing the history of different metals. If you are a metal lover or history lover, you can follow our website. For previous posts of this column please search the keyword “history”.

 

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

Discovery and application of vanadium | History of Vanadium

Discovery of vanadium

Andrés Manuel del Río
Andrés Manuel del Río

In 1801, the Mexican mineralogist Andrés Manuel del Río discovered a new element similar in nature to chromium and uranium when he studied lead ore. Its salt is red when heated in acid, so Leo named it red mud. However, it is actually vanadium.

 

In 1830, the Swedish chemist Nils Gabriel Sefström isolated a new element in the refining process of iron. Due to its brilliant color, he named it Vanadium under the name of the beautiful goddess Vanadis in Greek mythology. In the same year, the German chemist Friedrich Wöhler proved that Vanadium was the same element as the red element discovered by the early Andrés Manuel del Río – vanadium.

Henry Roscoe
Henry Roscoe

In 1867, the British chemist Henry Roscoe reduced the vanadium chloride (VCl3) with hydrogen to produce metal vanadium for the first time.

The origin of the name

A long time ago, a beautiful goddess named Vanadis lived in the far north. One day, a distant guest came knocking on the door. The goddess was sitting leisurely on the circle chair. She thought: If he knocked again, I would open the door. However, the knock on the door stopped and the guest left. Vanadis wants to know who this person is, why is he so lacking in self-confidence? So she opened the window and looked out. It turned out that a man named Wöhler was coming out of her yard. A few days later, the goddess heard someone knocking on the door again, and the knocking of the door didn’t stop until the goddess opened the door. This is a young and handsome man named Sefström. The goddess soon fell in love with him and gave birth to his son, vanadium.

The application history of vanadium

After discovering the metal of vanadium, people gradually learned about its properties and began to apply it to our daily lives. In 1882, a British company used vanadium-containing slag containing 1.1% vanadium to produce vanadium phosphate with an annual output of about 60 tons.

In the late 19th and early 20th centuries, Russia began to reduce iron and vanadium oxides by carbon reduction, and for the first time prepared vanadium-iron alloys (including V35% to 40%). From 1902 to 1903, Russia tested an aluminothermic method for the preparation of ferrovanadium.

At the end of the 19th century, the study also found that vanadium can significantly improve the mechanical properties of steel in steel, making vanadium widely used in industry. By the beginning of the 20th century, people began to mine vanadium.

So far, the world’s vanadium-producing ore is mainly composed of vanadium-titanium magnetite, and there are abundant resources in Russia, South Africa, China, Australia and the United States. In addition, vanadium uranium, bauxite, phosphate rock, carbonaceous shale, petroleum combustion ash, spent catalyst, etc. can also be considered as resources of vanadium.

This is a history column, aiming at introducing the discovery of different kinds of metals. If you are a metal lover or history lover, you can follow our website. For previous posts of this column please search the keyword “history”.

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