Synthetic diamond process can be specifically divided into two methods, direct and indirect method. Direct method uses instantaneous dynamic temperature and high pressure, high temperature and static two mixed techniques such as graphite as raw material to C directly into the diamond (meet under static pressure> 13GPa, temperature of 2000K and holding time> 1min; under dynamic conditions, pressure> 20 GPa); the indirect method uses static high temperature and pressure technology to react C elements with the specific metal and obtain synthetic diamond (the transition process is molten metal or alloy + graphite <=> C atom + metal atom or group of atoms <=> diamond + metal or alloy and some carbides).

Domestic synthetic diamond industry mainly is based on hexa-orientation anvil, which belongs to static catalyst method. The basic principle is use six tungsten carbide anvil in six surfaces, while the scope of the high-pressure cavity by the pyrophyllite hexahedron composed of such a graphite cavity under the catalytic effect of high temperature and press into a diamond. Pyrophyllite tetrahedron is a hydrous aluminum silicate layered structure, in the process of synthesis plays role in pressure transmission, sealing and insulation effect; Catalyst acts as a catalyst, can effectively promote the synthesis of diamond, and reduce the pressure required for the synthesis temperature, a common catalyst material Ni70Mn25Co5 alloy.

Anvil diameter is generally φ80mm - φ40mm, density 14.70-14.80g / cm3, hardness of about HRA89.5, diameter of the particles (2-3μm). Sintered tungsten carbide anvil service life is about 5,000 times ten thousand karats consumption> 3kg. Compared with the domestic synthetic diamond industry, foreign-related enterprises have begun to adopt YG12x fine particles carbide diamond anvils, hardness generally reach more than HRA90.5, bending strength of 3000MPa, the average service life is more than 8,000 times, ten thousand karats consumption <1.5kg. Therefore, by grain refinement to improve tungsten carbide anvil density, toughness, flexural strength and prolong the service life of, reduce the consumption, which is a inevitable trend anvil of anvil development.

Diamond is a kind of the hardest mineral consists of pure carbon in nature. It has many advantages, such as higher hardness, excellent wear resistance, which can be widely used in cutting, grinding and drilling industries. Early in the 18th century people began the study of synthetic diamond, but until the last century was able to achieve the preparation of artificial diamond precedent. Tungsten carbide anvil is a key component of the production of synthetic diamond, and it should withstand the alternating loads of high temperature and high pressure, whose life span will directly determines the cost of diamond synthesis production.

So it has higher requirements to tungsten carbide anvil properties: 1. high hardness and compression properties (HRA ＞85, above 5000MPa); 2. high strength and toughness (tungsten carbide anvil beveled at work entails considerably greater tensile stress> 35kg / mm2); 3. excellent heat resistance, wear resistance and corrosion resistance (in the process of synthetic diamond, the transition temperature of C element is about 2000℃, and the added catalyst is not only beneficial for the synthesis, but also not react with the anvil).

Tungsten carbide grades suitable for anvil include YG6, YG8, YG12x and so on. YG6 tungsten carbide is composed of 94% WC + 6% Co, mainly based on WC powder and Co powder with medium grains. Higher hard phase WC content to ensure the compression performance of tungsten carbide anvil. But the lower content of the binder phase Co will affect the tensile strength of the anvil, which will be easily cracked in the process of synthesis diamond. Furthermore, tungsten carbide YG6 anvil has some difficulties in the content of C controlling, which prone to appear free C or η phase and affect the properties of the anvil; YG8 tungsten carbide with medium grain consist of 92% WC and 8% Co, which is not only has excellent compression performance, but also has excellent tensile strength and longer service life, so fewer cracks occur in the early stage; YG12x tungsten carbide is a kind of alloy with fine grains. Under certain circumstances of Co content, the finer granularity of WC, correspondingly the density, the hardness, the compression performance and other composite properties will be remarkably improved. Therefore, refining the grain is a kind of ideal process of tungsten carbide anvil.

Tungsten granule is considered as flux of LECO S144DR carbon sulfur analyzer which plays an important role in enhancing liquid flow, controlling the temperature of combustion oxidation while analyzing carbon and sulfur. Generally, its shape is fine stuff with a size of 0.4-0.8μm. Tungsten granule accelerates the combustion reaction of inorganic material which has the function in light the fire, combustion-supporting. It can also melt of the oxidizing material of the sample’s surface to make flux have a good fluidity, which is conducive to oxidize the carbon and sulfur of the sample in a short time. Compared to CS230, the greatest different is that S144DR is a tube furnace which belongs to external heating, its sample is burned in a high-temperature tube furnace. CS230 is a high-frequency heating furnace, high-frequency furnace using a metal sample to generate eddy current in a high frequency producing CO₂ and SO₂ in oxygen.

LECO S144DR carbon sulfur analyzer mainly uses a size 0.7-1.2μm of magnesium perchlorate as a desiccant, and glass wool is used for filtering dust. Purity of oxygen should reach above 99.5% whose outlet pressure is 0.26MPa. Its basic structure consists of a tube furnace, infrared absorption system, purification system, constant-temperature system, gas system, steady flow systems, and data processing and control system. Melting and combustion of the sample is mainly carried out in a tube furnace. Infrared absorption system is used for measuring SO₂, the purification system is used for purifying carrier gas and the reaction gas to remove its dust, impurities and moisture. Thermostat system allows temperature of measured gas and the detector cell keep constant. The reaction gas is offered by the gas system. Steady flow system is mainly to control the flow of the carrier gas, the main data processing and control system is to control of the instrument and calculate sulfur content.

Operational principle of this type of analyzer is first to weighing a certain quality of the sample into the flow of oxygen, combusting in a high-temperature furnace, sulfur is converted to sulfur dioxide, flowing with oxygen through the infrared absorption cell, and detect the sulfur.

For the determination of carbon, the main way is to combust carbon which can be converted to carbon monoxide and / or carbon dioxide in oxygen. Using infrared absorption spectroscopy of carbon dioxide and carbon monoxide in oxygen to determine carbon. The determination of sulfur is first to burn sulfur in oxygen which is converted to sulfur dioxide. Then, sulfur is detected infrared absorption spectroscopy of sulfur dioxide. The electronic control part of the carbon sulfur analyzer consists of infrared, air flow control panel, and stimulus airflow control panel, and power control rack, incubator heating control panel, computers and other electronic components.

Path of the carrier gas of the analysis of the gas flow is to let oxygen pass the rare earth oxide copper oxide of inlet to remove the carbon monoxide methane and other impurities of carrier gas. To remove its carbon dioxide and moisture with soda asbestos and magnesium perchlorate. Then, it would pass the oxygen lance and carrier gas inlet into the furnace end. Gas of samples which is generated in combustion tube which is made of fused silica would go with carrier gas after magnesium perchlorate to remove its moisture, and then, entering into detector cell of sulphur. After that, transfer sulfur dioxide into sulfur anhydride and remove it. Detection of carbon dioxide of carrier gas would be in process of high carbon and low carbon at the both ends of gas path of the instrument.

When LECO CS230 carbon sulfur analyzer works with tungsten particles, its operational principle is first to put a certain quality of sample into a high-frequency magnetic field which has been passed through an oxygen stream. The sample and flux would be induced and heating, combusting in oxygen, carbon and sulfur of sample reacts with oxygen to produce carbon dioxide and sulfur dioxide which will accompany with the carrier gas into the gas system. They will first to reach the sulfur dioxide detector testing pool to determine sulfur, and then using thermal oxidation of copper to convert carbon monoxide into carbon dioxide. Next, sulfur dioxide will be converted into sulfur trioxide, and then it would be absorbed by the plastic which has a strong adsorbability. Then, the sample gas would go through the high and low content of carbon dioxide of the infrared detector cell to detect carbon.

LECO brand initially established in 1936 that is an abbreviation of Laboratory Equipment Corporation. In 1936, the brand launched the first commercial analyzer of carbon, sulfur, nitrogen, oxygen, hydrogen in the world, pioneering a precedent for analysis and the rapid analysis technology of industrial equipment. LECO decades has been maintained its leadership in analysis techniques. Currently, it has a diversified product line of laboratory analytical instruments, possessing the leading competitive products in the field of HX-MIAS, spectrum analyzer, gas chromatograph, which is widely used in various industries. LECO devote itself to develop and improve various analytical techniques and equipment for many years that brings more technology to more industries that need better, faster results. For example, LECO carbon sulfur analyzer occupies a large market in element analyzer areas, so in the late 1970s, this brand’s carbon and sulfur analyzer had to enter the Chinese market, there are more than 3,000 users and over 4000 instruments in China.

With the common using of LECO carbon sulfur analyzer in China, and its maintenance and other after-sales service is constantly being improved. In China, there are more than a dozen technical engineers with a professional and technical training to provide high-quality services for the maintenance of the analyzer. In order to reduce the rate of equipment failure, LECO has developed equipment maintenance contracts, within a predetermined range, a professional maintenance personnel will check up and repair the analyzer regularly inspection and maintenance in order to keep it in a normal working condition.

This brand's carbon sulfur analyzer series uses Cornerstone software for analyzing that allows users to achieve a complete control of analysis, method setting, online diagnostics, data reports. This software technology allows users to complete all the work routine analysis in an interface, which only needs for a short time and easy to operate. Tungsten granule has a good fluxing effect, the using of tungsten particles as the flux of carbon sulfur analyzer will greatly enhance the accuracy of the analysis results.

As a new and high-tech level analyzer, carbon sulfur analyzer is widely applied in analyzing the content of carbon and sulfur of the alloy, cast-iron, lime and other solid and fluid materials. It has a high accuracy and a wide measurement range when analyze carbon and sulfur. The modular and integrative design of the whole structure of the analyzer achieves an easier operation, a faster analysis, a greater precision of analysis, a more reliable working of instrument. LECO carbon sulfur analyzer has been kept a leading edge in its technology, and has a number of technology patents, which has become the most well-known brands of analytical instruments in the world.

Operational principles of LECO carbon sulfur analyzer and tungsten granule mainly include the operation procedure before starting, the opening of host, the entering of the main program, dank correction and the shutdown operation. First of all, startup the UPS equipment, the power supply is checked to ensure whether it can be used normally or not. Then turn off the air switch and the stabilized voltage supply, check whether the output stabilized voltage supply is 220V or not. Under normal circumstances of the input of power, then get into the boot process. Next, open the air supply of the carrier gas O₂ and power gas Ar, and adjust it into the appropriate pressure.

The carrier gas O₂ is 0.26MPa, power gas Ar is 0.26MPa. Firstly, turn off of power switch of the furnace equipment (switch is located in the front of lower part of the stove, a black switch), then turn off the power switch of the instrument detector. You can see that some electronic tube is lit in the furnace crucible, the flowmeter of the float should be placed at 3L / min. The mainframe computer and monitor power is turned on while the printer power and balance power is turned on. Since the balance is in balance and it display 0.0000, double-clicking the CS230 icon on your desktop, entering CS230 analysis process.

After the analyzer and computer communication can be carried out normally, checking the air leak condition, then enter the sub-menu to view corresponding parameters and graphics, the next step is to be tested after a stable of data in detection pool. Finally, turn off the software first before shutting down, then turn off the switch and the analyzer switch in the front of stove, then turn off the gas source, and the power.