Brief Introduction
Polycrystalline diamond and oil reamer professional composite sheets are generally manufactured by static ultra-high pressure-high temperature method, and the equipment used mainly includes hexahedral diamond special hydraulic presses and annual wheel double presses. These ultrahigh pressure equipments and synthetic synthetic diamond single crystals The equipment used is exactly the same.
1) Polycrystalline diamond and oil reamer professional composite sheet production process, see Figure 4 and Figure 5.
2) static ultra-high pressure equipment. At present, there are two types of static ultra-high pressure equipment for producing polycrystalline diamond and oil reamer professional composite sheets: China (including a few foreign manufacturers) generally adopts a hinged six-ply super-high-pressure equipment (or six-surface press machine). ) As the main equipment; abroad is mainly used year-round two-pressure pressurization equipment (or two-pressure press). The advantages of the six-ply super high-pressure equipment for the production of polycrystalline diamond or oil reamer professional composite sheets are: the generated pressure field is closer to the hydrostatic pressure, the stress field state in the synthesis cavity is more reasonable; the machine work efficiency is high, and the equipment cost is high. Relatively inexpensive. The disadvantage is that it is difficult to increase the size of the synthesis chamber. The advantages of the professional composite sheet produced by the polyhedral diamond or oil reamer on both sides of the super high pressure equipment are: the control precision of pressure and temperature is high; the size of the synthesis chamber is easy to realize, and it is suitable for producing large-size products or a single synthesis of multiple product. The disadvantage is the high operating cost of the equipment.
Performance
1) Abrasion resistance. When polycrystalline diamond is used as a cutting or drilling tool material, its wear resistance has a direct correspondence with the service life of the tool, so the wear resistance becomes the most important performance index of polycrystalline diamond. The wear resistance of polycrystalline diamond is usually expressed as the wear ratio. At present, the method for determining the wear rate of polycrystalline diamond adopts the industry standard "method for measuring the wear ratio of synthetic diamond sintered body."
2) Thermal stability. Thermal stability, also known as heat resistance, is generally expressed in terms of heat-resistant temperature, and refers to the maximum heat treatment temperature that polycrystalline diamond can withstand without changing its performance. Thermal stability is one of the important performance indicators of polycrystalline diamond. It involves the process of making polycrystalline diamond tools and the environment in which the tools are used. It is a performance parameter that tool makers must consider. The use of too high a temperature during processing or use of the tool at an excessively high temperature will deteriorate the use of polycrystalline diamond tools.
3) Impact toughness. Impact toughness refers to the maximum ability of a polycrystalline diamond or oil reamer professional composite sheet to fail under impact loads. This performance index is crucial for the polycrystalline diamond tool to exhibit its high hardness, good wear resistance and long life.
4) Flexural strength. A three-point bending test was used to determine the flexural strength of polycrystalline diamond. Polycrystalline diamond specimens can be made into a rod shape or a round shape.
5) Hardness. Polycrystalline diamonds have high hardness values, second only to single crystal diamonds, and are generally measured in Knoop hardness.
6) Conductivity. In general, polycrystalline diamond is not very conductive and has a large resistance value. Ordinary EDM equipment is difficult to process polycrystalline diamond, and there must be a dedicated EDM power source to obtain an acceptable processing speed. Even so, special EDM equipment processing polycrystalline diamond is still much slower than ordinary EDM equipment processing of metal materials.
7) Corrosion resistance. After growth-sintering polycrystalline diamond is heated for a long period of time in acid or alkali solution, its mechanical properties (hardness, wear resistance, etc.) remain basically unchanged. After the growth-sintering polycrystalline diamond is treated with a strong acid, the conductivity of the PCD is significantly decreased due to the leaching of polycrystalline diamond (PCD) after the metal phase as a binder reacts with the acid. Sintered polycrystalline diamond diamond and the binder phase of the main phase of the acid and alkali corrosion resistance. Polycrystalline diamond in the acid or alkali solution heat treatment for a long time, its mechanical properties and physical properties remain basically unchanged.
Related Products