Introduction to the Use and Application of Chromium

Chromium is a hard metal that is resistant to corrosion. It is widely used in metallurgy, chemical, cast iron, fire-resistant, and high-end technology. The specific application ratio is shown in the following figure:

specific application ratio of Chromium

Chromium in the Metallurgical Industry

Chromium is a hard metal, and is often incorporated into steel to make hard and corrosion-resistant alloys. Those alloys are mainly used to refine stainless steel, heat-resistant steel and various electric heating materials. When stainless steel encounters corrosive substances, its surface will form a fine and solid chrome oxide film, which protects the internal metal from corrosion. Some stainless steel can maintain its excellent performance even at high temperature of 800 °C. Chrome steel is a good material for manufacturing machinery, tanks and armored vehicles.

Chromium tank

Chromium in the Chemical Industry

Chromium salt is one of the main varieties of inorganic salts and is the main raw material in the chemical industry. It is widely used in daily life, including electroplating, tanning, printing and dyeing, medicine, fuel, catalyst, oxidant, match and metal corrosion inhibitor.

Chromium barrel

At the same time, metallic chromium has been listed as one of the most important coating metals–chromium sputtering targets for sputter deposition and chromium evaporation materials for evaporation coating. In most cases, the chrome layer is specifically used as the outermost coating for the parts. When chrome is applied, the thinner the chrome layer, the closer it is to the surface of the metal. The chrome layer on the inner walls of some is only five thousandths of a millimeter thick, but after firing thousands of rounds and bullets, the chrome layer still exists. If the surface is not chrome-plated, the service life of most parts will be greatly shortened due to wear and corrosion, and must be replaced or repaired frequently. Therefore, chrome plating is widely used in many industrial manufacturing.

Chromium for Refractory and Cast Iron

Chromite has a high melting point of 1900 °C – 2050 °C, and it can maintain the volume at high temperature and does not react with any slag, so it is used as a lining for refractory materials, steelmaking furnaces and non-ferrous metal smelting furnaces.

chrome bricks

Chromite can be used to make chrome bricks, chrome-magnesia bricks and other special refractory materials. In addition, chromium is also used in cast iron, such as chromium cast ductile iron, which has high strength, high elongation, high impact value and low hardness.

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Physical Vapor Deposition: Sputter Coating & Evaporation

Physical vapor deposition processes use vacuum technology to create a sub-atmospheric pressure environment and an atomic or molecular condensable vapor source (from a solid or liquid surface) to deposit thin films and coatings. Sputtering deposition and vacuum evaporation are among the more well known.

physical vapor deposition sputtering evaporation

Sputtering deposition

The sputtering deposition is an etching process that alters the physical properties of a surface. In this process, a gas plasma discharge is set up between two electrodes: a cathode plating material (the sputter coater targets) and an anode material (the substrate). The film made by sputter coating are thin, ranging from 0.00005 – 0.01 mm. Chromium, titanium, aluminum, copper, molybdenum, tungsten, gold, and silver are typical sputter coating targets.

Sputter coated films are used routinely in decorative applications such as watchbands, eyeglasses, and jewelry. Also, the electronics industry relies on heavily sputtered coatings and films, such as thin film wiring on chips and recording heads as well as magnetic and magneto-optic recording media. Companies also use sputter deposition to produce reflective films for large pieces of architectural glass used in the automotive industry. Compared to other deposition processes, sputter deposition is relatively inexpensive.

vacuum coating

Vacuum Evaporation

The vacuum evaporation is a process of reducing the wastewater volume through a method that consists of concentrating a solution by eliminating the solvent by boiling. In this case, it is performed at a pressure lower than atmospheric pressure. Thus, the boiling temperature is much lower than that at atmospheric pressure, thereby resulting in notable energy savings. The basic components of this process consist of: evaporation pellets,  heat-exchanger, vacuum, vapor separator, and condenser.

Vacuum evaporation is used in the semiconductor, microelectronics, and optical industries and in this context is a process of depositing thin films of material onto surfaces. High-purity films can be obtained from a source evaporation material with high purity. The source of the material that is going to be vaporized onto the substrate can be a solid in any shape or form (usually pellets). The versatility of this method trumps other deposition processes. Also, when the deposition is not desired, masks are utilized to define the areas on the substrate for control purposes.

Information from Stanford Advanced Materials. Please visit https://www.sputtertargets.net/ for more information.

Smelting Technology of Metal Titanium and Titanium Alloy

In the industrial production of titainum and titanium alloys, the most commonly used techniques are vacuum arc remelting (VAR) and cold hearth melting.

Vacuum Arc Remelting

VAR technology can refine the ingot structure in titanium alloy smelting and improve the purity of the product. The main developments of this technology in recent years are as follows:

  • Fully-automatic VAR re-dissolution process

Advanced computer technologies are applied to VAR processes. For example, automated electronic control box data collection systems can establish excellent smelting modes for specific ingots and alloys. In addition, it can analyze the problems in the smelting process and improve the metal yield.

  • Ingot size enlargement

Large VAR furnaces can smelt titanium ingots with a mass of 30t. At present, the tonnage of vacuum self-consumption arc furnaces for molten titanium is mostly 8-15t.

  • Different power supply methods

The power supply mode adopts a coaxial power supply mode, which can cancel the magnetic field and prevent segregation.

  • Development of numerical simulation technology

Domestic and foreign scholars have made some progress in using the numerical simulation method to study the VAR process. The distribution law of the ingot temperature field has been successfully explored and a model for predicting the solidification microstructure, ingot composition and defect distribution has been established.

Cold hearth Melting

Cold hearth melting uses a plasma (Plasma Arc) or an electron beam (Electron Beam) as a heat source, and can be divided into two processes of plasma cold bed furnace and electron beam cold bed furnace smelting. Electron beam cold-hearth melting has many advantages over vacuum arc melting:

1 Various forms of raw materials such as residual materials, loose titanium sponge and titanium shavings, and economical raw materials can be used;

2 It can remove high-density impurities such as molybdenum (Mo), tungsten (W) and tantalum (Ta), low-density impurities such as cyanide and volatile impurities, and is an important technology for pure titanium alloy materials;

3 Improve the yield of metals by producing ingots of various cross-sections.

Information from Stanford Advanced Materials (SAM) Corporation, a global sputtering target manufacturing company.

Pure Metal Sputtering Target: Silver Sputter Target

About Pure Metal Element Silver

Siver is a very malleable metallic chemical element with atomic number 47 that is capable of a high degree of polish, has the highest thermal and electric conductivity of any substance. Silver sputtering target is used as decorative coatings and antibiotic coating in medical devices.

Silver Sputtering Target Specification

SAM Sputter Taget

Product Silver Sputtering Target
Brand Stanford Advanced Materials
Category Pure Metal Sputtering Target
Material Type Silver
Symbol Ag
Atomic Number 47
Color/Appearance Silver, Metallic
Melting Point 962 °C
Theoretical Density 10.5 g/cc

Available Sputtering Target Dimensions

A comprehensive range of sizes of SAM’s sputtering targets are available to accommodate the requirements of most popular deposition tools.

silver sputtering target different dimensions

  • Disk targets, column targets, step wafer targets, plate targets
  • Rectangular targets, slice targets, step rectangular targets
  • Tubular targets / rotation sputtering target

Available Silver Sputter Target Purity

99.9% (3N), 99.95% (3N5), 99.99% (4N), 99.999% (5N), 99.9995% (5N5), 99.9999% (6N)

Silver Sputtering Target Applications

Physical vapor deposition (PVD) of thin films, laser ablation deposition (PLD), magnetron sputtering for semiconductor, display, LED and photovoltaic devices.target bonding

Each target can be designed to fit customer specified backing plates or cups with either indium/tin or silver epoxy bonding.  Bonding service is available on oxygen free copper backing plate.

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Related: Silver Sputtering Target Price

Basic Knowledge of Refractory Metal Tantalum

Tantalum Overview

Tantalum is part of the refractory metal group and it has good physical and chemical properties.

Tantalum has high hardness that can reach 6-6.5. Its melting point is as high as 2996 ° C, only after carbon, tungsten, rhenium and osmium. Tantalum is malleable and can be drawn into a thin foil. Its coefficient of thermal expansion is very small, and it only expands by 6.6 parts per million per degree Celsius. In addition, it has a strong toughness and is superior to copper.

Refractory Metal tantalum
Refractory Metal Tantalum

Tantalum does not react with hydrochloric acid, concentrated nitric acid and “aqua regia” under both cold and hot conditions. And tantalum is only corroded by concentrated sulfuric acid at temperatures above 150 °C. Tantalum can be considered one of the most chemically stable metals at temperatures below 150 °C. It is also highly resistant to corrosion because of the formation of a stable tantalum pentoxide (Ta2O5) protective layer on its surface.

Tantalum Application

Tantalum can be used to manufacture evaporation vessels, as well as tubes, rectifiers, and electrolytic capacitors. Tantalum forms a stable anodized film in an acidic electrolyte. The electrolytic capacitor made of tantalum has the advantages of large capacity, small size and good reliability. Tantalum capacitors are the most important use of tantalum, around 2/3 of the full use of tantalum. Tantalum is also the material for making electron-emitting tubes and high-power tube parts. Anti-corrosion equipment made by Tantalum is used in the chemical industry such as strong acid, bromine and ammonia producing industries. The metal tantalum can be used as a structural material for the combustion chamber of an aircraft engine. Tantalum is easy to form and can be used as support accessories, heat shields, heaters and heat sinks in high temperature vacuum furnaces. Tantalum can also be used as orthopedic and surgical materials. Tantalum sputtering targets and tantalum evaporation materials are important coating materials in physical vapor deposition.

tantalum capacitor
tantalum capacitor

High Purity Tantalum Preparation

The chemical inertness and relatively low price of tantalum make it a good alternative to platinum.  However, high-purity tantalum is not easy to get because it is always found together with niobium in the mineral groups of tantalite, columbite, and coltan. To get high purity tantalum, here are several methods.

1 Tantalum powder can be obtained by metal thermal reduction (sodium thermal reduction) method. The potassium fluotantalate is reduced with sodium metal under an inert atmosphere: K2TaF7 + 5Na-→Ta+5NaF+2KF. The reaction was carried out in a stainless steel tank, and the reaction was quickly completed when the temperature was heated to 900 °C. The powder prepared by this method has irregular grain shape and fine particle size, and is suitable for making tantalum capacitors.

2 The tantalum powder can also be obtained by molten salt electrolysis: a molten salt of a mixture of potassium fluoroantimonate, potassium fluoride and potassium chloride is used as an electrolyte, and tantalum pentoxide (Ta2O5) is dissolved therein and electrolyzed at 750 °C. This method can obtain a bismuth powder having a purity of 99.8 to 99.9%.

3 Tantalum can also be obtained by carbothermal reduction of Ta2O5. The reduction is generally carried out in two steps: first, a mixture of a certain ratio of Ta2O5 and carbon is made into tantalum carbide (TaC) at 1800 to 2000 ° C in a hydrogen atmosphere. Then, TaC and Ta2O5 are prepared into a mixture in a certain ratio, and reduced to tantalum in a vacuum.

4 Tantalum can also be obtained by thermal decomposition or hydrogen reduction of chloride. The dense metal crucible can be prepared by vacuum arc, electron beam, plasma beam melting or powder metallurgy.

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