In nature, phosphorus is a substance that exists in many forms, such as white phosphorus, red phosphorus, black phosphorus, and purple phosphorus. Widely used in the chemical industry, red phosphorus is a common material in the sintering process of diamond segment.
In fact, Most of the metal powders of diamond segments do not need to add phosphorous powder. The main reason is that the addition of phosphorous greatly increases the uncertainty in the sintering process. For the proportion of metals, the sintering process requires more stringent requirements. For example, the sintering temperature also has a great influence, because once the excessively high temperature reaches or exceeds the boiling point of phosphorus, the phosphorus powder will volatilize, which affects the stability of the segment quality.
In modern industry, due to the reasons we have described above, phosphorous powder does not appear alone, but appears in the production process of diamond segments through phosphorus-iron alloy powder as an additive component. After special treatment, this extremely fine metal alloy powder has a great difference from ordinary iron alloys. The content of easily oxidized elements in this powder is greatly reduced. This material is agglomerated by the sintered segments, and the carcass has extremely strong crack resistance, that is to say, its brittleness has been greatly improved, making iron metal more rigid. And long-term tests have found that the higher the phosphorus content of the sintered ferro-phosphorus alloy powder, the possibility of diamond segment fracture is greatly reduced.
The second benefit of ferrophosphorus alloy is its strong dispersibility, also known as ductility, The main parameter is elongation. The higher the elongation, the better the ductility and the stronger the flexibility of the final segment. The stronger the flexibility of the segment, the smaller the head-turning situation, which greatly increases the safety of the diamond segment.
In the sintering process, the ferro-phosphorus alloy is formed into a sintered steel with excellent toughness through high temperature and high pressure. And during the sintering process, the molecular structure and atomic structure are quickly and tightly combined, and the volume is greatly reduced, and due to the denser space of the molecular and atomic structure, the strength of the material is also greatly improved. Such materials have the best quality of sintered materials.
In general, the ferro-phosphorus alloy powder has an activation sintering effect. During the sintering process, it can increase the surface tension of the pores to make the pores of the product tend to be spheroidized, play the role of filling the pores, and increase the density of the product. The spherical pores greatly reduce the generation of fracture sources and improve the strength of the product. At the same time, the plasticity and toughness of the material will not be reduced. From the technological point of view, P and FeP form a eutectic reaction during sintering, which can accelerate the sintering process. Reaction formula: FeFe3P-L(P), the P in the liquid phase is quickly taken around the iron particles under the action of capillary force, and it will quickly diffuse into γ-Fe, and after cooling, it will be dissolved in α-Fe(P ), so that the product is strengthened. In soft magnetic materials, P can increase the resistance value of the product, reduce the eddy current effect, and reduce the calorific value of the product.
When applying ferro-phosphorus alloys, the carbon content should be strictly controlled. Because of the high carbon content and phosphorus, the material will become brittle. During the sintering process of the segment, if the temperature is too high, the diamond will change graphite. This carbonization process will not only cause product quality problems due to the carbonization of the diamond, but also cause the bit material to become brittle due to the reaction of phosphorus and carbon. Broken teeth of the segment.
Due to the very high strength of ferro-phosphorus alloy powder, it is currently only applied to a small number of iron-based segment. However, in the long-term practical application process, people have found that a reasonable proportion of ferro-phosphorus alloy can actually greatly improve the strength and toughness of the diamond segment. It can also greatly increase the rigidity of the carcass and improve the quality and stability of the segment.