Tungsten diiodide ( WI₂) is the iodide of tungsten (II), which is the metal salt of tungsten and hydroiodic acid. Its English name is Tungsten Diiodide, CAS number : 13470-17-2, relative molecular mass : 437.65.

Tungsten diiodide(IUPAC name: Tungsten Diiodide, molecular formula:WI₂) is an inorganic compound composed of tungsten and iodine after chemical reaction. The valence electron configuration of tungsten atom in tungsten diiodide is 5d⁴6s², which can form compounds with oxidation value from +2 to +6. Among them, the compounds with oxidation value of +6 are more stable. In tungsten diiodide, the valence state of tungsten is +2, and iodine is -1. So the molecule is composed of one tungsten atom and two iodine atoms.

To improve the service life of cemented carbide top hammer and pressure cylinder, thereby reducing hammer consumption:

1. Improve the performance of cemented carbide

(1) Increasing the cobalt content can improve the strength of the cemented carbide. From the comprehensive consideration of economic benefits, the cobalt content in a certain part can only be increased. Experiments show that increasing the cobalt content can improve the service life of the cemented carbide anvil and the pressure cylinder.

(2) The grain size of tungsten carbide has obvious influence on the performance of cemented carbide. With the increase of WC particle size, the compressive strength, hardness and elastic modulus decreased, while the flexural strength increased. Therefore, controlling the particle size of tungsten carbide is an effective way to improve the life and reduce the plastic deformation.

(3) If the structure of the cemented carbide is defective, it will cause stress concentration during synthesis, accelerate the fatigue failure of the anvil, and reduce its life. In order to improve the life of the top hammer, some alloying elements (such as niobium carbide, titanium carbide, vanadium carbide, tantalum carbide, etc.) The service life of the top hammer is greatly improved.

2. Change the shape of the top hammer

Some researchers suggested that if the flat-bottomed top hammer is changed to a spherical bottom, the strength of the spherical top hammer is better than that of the plane, because the uniformity of the force on the spherical top hammer is better, and the maximum tensile stress value acting on the 46° slope of the top hammer, The spherical surface is smaller than the flat surface, the maximum shear stress value acting on the central axis at 1/3 of the top hammer height from the top surface, the spherical surface is smaller than the flat surface, and the maximum compressive stress value on the 46° inclined surface is larger than that of the flat surface Small, changing the shape can also reduce the height of the anvil, save alloys, and reduce the "size effect". Therefore, changing the top hammer to a ball bottom can not only improve the stress distribution state in the top hammer body, reduce the peak value of external stress and thermal stress, improve the life of the top hammer, but also save alloy materials and reduce the "scale effect".

3. Carbide heat treatment

Heat treatment can improve the bending strength, impact toughness and durability of the top hammer, reduce brittle fracture, reduce porosity, increase density, reduce the source of fracture, and thus increase the service life of the top hammer. Heat treatment can change the magnetic properties, increase the coercive force and reduce the magnetic permeability. After heat treatment of fine-grained cemented carbide, the toughness will be improved, the loading deformation energy will be increased, and the durability in the high-pressure chamber will be improved.

4. Appropriately increase the thickness of the gasket

Increasing the thickness of the gasket is beneficial to prolong the life of the anvil. However, increasing the thickness is not arbitrary, and should be limited to not reducing the stability of the gasket and reducing the deformation of the gasket.

In order to achieve sufficient sealing conditions, improve the utilization rate of external load pressure and protect the function of the top hammer, it is required that the side length of the top hammer surface and the width of the chamfer and the side length of the pyrophyllite block have a certain proportional relationship, and the angle of the top hammer chamfer Be suitable. This is mainly to ensure that the pyrophyllite gasket has an appropriate width and thickness, an important condition for forming sufficient sealing force and reducing the influence of thermal stress, so as to achieve the effect of maintaining a constant pressure in the cavity and prolonging the service life of the anvil.

5. Improve the neutrality of the equipment, and adjust the anvil in place

Before starting up, check the centering synchronization of the equipment, ensure the accuracy of the pressure holding performance and the stability of the heating system, check whether the various parts of the press are normal, and the anvil must be accurately installed and debugged in place.

6. Cooling water cooling

Adding appropriate cooling water during synthesis can effectively lower the temperature and reduce thermal stress concentration.

7. Reduce synthesis pressure and temperature, shorten synthesis time

While ensuring the synthesis effect, try to reduce the pressure and temperature of the synthesis and shorten the synthesis time.

8. In order to eliminate the internal stress of the top hammer, it is recommended to put the top hammer and steel ring on hold for two or three months, and then use them after the internal stress is released to reduce longitudinal splitting or top hammer cracks and crushing.

9. The baking process of auxiliary materials such as pyrophyllite should be strictly controlled.

10. Adding a layer of protective metal Mo, Ti, etc. on the surface of the conductive top hammer can improve the temperature distribution of the top hammer, make the top hammer evenly heated, improve thermal stress concentration, and reduce hammer consumption.

11. Classify and use the top hammer, such as using ultrasonic and magnetic flaw detection to inspect the quality of cemented carbide molds. Those with micro defects are used for non-electric heating hammers, and those without defects are used for electrified heating hammers. This will prolong the service life of the top hammer Clearly there are benefits.

Tungsten carbide anvil is a key component for the synthesis of superhard materials such as artificial diamond by high temperature and high pressure (HPHT). The anvil is an important consumable inside the synthetic press, and the synthetic press is the core equipment for producing diamond single crystals and growing diamonds. Since the anvil is subjected to complex and severe compression, shearing, and tensile stresses, and the instantaneous temperature of the hammer surface reaches 500-600°C during heating, which requires nearly ten thousand times of repeated service life, the anvil is mostly made of tungsten drill series. Made of high-quality alloy, it has the characteristics of high hardness, good rigidity, high strength and excellent heat resistance.

The main products of synthetic diamonds include industrial diamonds and lab-grown diamonds. Among them, industrial diamonds are mainly used in mineral development, machinery manufacturing, household appliances, photovoltaic power generation and other fields; the application fields of cultivated diamonds include jewelry, precision optical instruments, cutting molds, optical materials, etc.

At present, one of the core high-pressure and high-temperature equipment for the production of synthetic diamond in my country is the six-sided top press, and the cemented carbide anvil is the key consumable inside the six-sided top press. The working principle of the cemented carbide top hammer is to equip a cemented carbide top hammer on each of the six sides of the six-sided top press. Under high temperature and high pressure conditions, the graphite in the high-pressure cavity is converted for the diamond process.

Grade

Grades suitable for cemented carbide anvils include YG6, YG8 and YG12x, etc. YG6 cemented carbide, the composition is 94%WC + 6%Co, mainly medium-sized WC powder and Co powder. The higher WC content of the hard phase ensures the compressive performance requirements of the cemented carbide anvil. However, the low content of Co in the binder phase affects the tensile strength of the anvil to a certain extent, and cracks are prone to occur during the diamond synthesis process. In addition, there are certain difficulties in controlling the C content of the YG6 cemented carbide anvil, and free C or η phases are prone to appear during the synthesis process, which affects the performance of the anvil; YG8 cemented carbide contains 92% WC And 8% Co belongs to medium grain cemented carbide, which not only has good compressive properties, but also has good tensile properties. It has a long service life, and there are fewer cases of cracking hammers in the early stage; YG12x cemented carbide is a kind of fine-grained cemented carbide. When the Co content is constant, the finer the grain size of WC, the corresponding density, The comprehensive properties such as hardness and compressive strength have been significantly improved, and it is an ideal one among cemented carbide anvil materials.

Performance

1. High hardness and compression resistance (HRA>85, bearing pressure above 5000MPa);

2. High strength and high toughness (the slope of the cemented carbide anvil must bear a large tensile stress > 35kg/mm2 when it is working);

3. High temperature resistance, wear resistance and corrosion resistance (in the process of synthesizing diamond, the transition temperature of C element is about 2000 ℃, and the added catalyst should not only facilitate the synthesis but also not react with the top hammer).

Chinatungsten Online (Xiamen) Manu. & Sales Corp. specializes in the production of hard paper alloy six-sided anvils, which can be customized according to customer sizes or samples (drawings).

A team of Indian scientists have developed a new method of deposition of Nickel-Tungsten alloy coatings on high-performance materials in engineering applications can replace environmentally toxic chrome coatings. The coatings obtained are also highly corrosion-resistant and useful for the plastic ware industry.

Ammonium metatungstate (AMT) can be synthesized by reacting sodium tungstate with ammonium chloride in aqueous solution, followed by acidification with hydrochloric acid. The reaction can be summarized by the following equation:

Ammonium metatungstate (AMT) is a white crystalline powder that is used in the production of tungsten metal, tungsten carbide, and other tungsten compounds. It is a stable compound under normal conditions, but it can decompose at high temperatures or in contact with strong acids or oxidizing agents.

Here are some guidelines for the safe storage and handling of ammonium metatungstate:

Storage: AMT should be stored in a cool, dry, well-ventilated area away from incompatible materials such as strong acids, oxidizing agents, and combustible materials. The storage area should be clearly labeled and access should be restricted to authorized personnel only.

Handling: When handling AMT, wear appropriate personal protective equipment such as gloves, goggles, and a lab coat. Avoid direct contact with skin, eyes, and clothing. AMT should be handled in a fume hood to prevent inhalation of the powder. Use a dust mask or respirator if necessary.

Transportation: AMT should be transported in a sealed, unbreakable container to prevent accidental spills or leaks. The container should be labeled with the name of the chemical, the hazard warnings, and the name of the supplier.

Disposal: AMT should be disposed of according to local, state, and federal regulations. It should not be disposed of in regular trash or poured down the drain. Contact your local hazardous waste disposal facility for instructions on proper disposal.

In summary, ammonium metatungstate should be stored in a cool, dry, well-ventilated area away from incompatible materials, handled with appropriate personal protective equipment, transported in a sealed, unbreakable container, and disposed of according to local regulations.

Ammonium metatungstate (AMT) is a white crystalline powder that is used as a precursor to make tungsten metal and tungsten alloys, as well as a catalyst and a pigment in various industrial applications.

The price of ammonium metatungstate (AMT) can vary depending on several factors such as the quality, quantity, purity, and supplier.

Ammonium metatungstate (AMT) can be used as a thermal insulating material due to its unique thermal properties. When AMT is heated, it decomposes to form tungsten oxide, which has excellent thermal stability and a high melting point. This makes it an ideal material for use in high-temperature applications.