Application of Brazing Technology in Diamond Tools
Author: yisainuo Time: 2017-05-27 18:19:02
Due to the high interfacial energy between the diamond and the general metal alloy, the diamond particles can not be infiltrated by the general low melting alloy, the adhesion is very poor, the traditional manufacturing technology, the diamond particles only by the carcass After the cold shrinkage generated mechanical clamping force embedded in the matrix metal base, and did not form a solid chemical bonding or metallurgical bonding, resulting in diamond particles easy to work with the matrix metal base separation, greatly reducing the diamond tool life and performance level. Most of the pregnant minted tools have a lower utilization of diamonds, and a lot of expensive diamond work falls off the waste. Lin Zengdong and other first use of diamond surface metallization technology to give the diamond surface many new features, such as excellent thermal conductivity, good thermal stability, improve its original physical and chemical properties, improve its metal or alloy solution infiltration.
Diamond surface metallization problem 70s of last century caused a high degree of attention at home and abroad diamond tool manufacturing industry. Many people committed to the sintering process to achieve the diamond surface metallization study, the addition of carcass material or diamond surface pre-coated with strong carbide metal powder (this diamond is not heated before the chemical reaction with the coating, can only belong to the diamond package Clothing) to expect them to sinter the process to achieve a chemical bond to the diamond. Although the literature has demonstrated that some metals, such as tungsten (not oxidized) at lower temperatures (around 800 ° C), can form WC layers on the diamond surface.
However, from the realization of the diamond surface pre-metallization process, the need for vacuum conditions, 600 ℃ above heating for 1 hour to get the ideal binding force. To the current commonly used pregnant diamond cutting tool sintering conditions, non-vacuum or low vacuum does not exceed 900 ℃ heating about 5 minutes, is unlikely to make the diamond surface to generate a metal layer. Because both the active metal atoms (Ti, V, Cr, etc.) are enriched to the surface of the diamond, the interfacial reaction also achieves the atomic diffusion process of the binder and the diamond metallurgy, and the process is extremely insufficient according to the temperature used for hot pressing and for such short periods of time. Under solid-phase sintering conditions (sometimes with a small amount of low-strength low-melting metal or alloy liquid phase), the carcass on the diamond chemical bonding or metallurgical bonding is very weak or not formed at all.
Diamond surface pre-metallization is not the ultimate goal, but only with the expectations of the realization of chemical metal metallurgy metal combination of one of the measures. After the diamond was sintered into the saw (drill) teeth, the diamond was lost on the broken surface, and the surface of the diamond residue was very smooth. This phenomenon seemed to indicate that the diamond and the carcass had not yet reached the chemical Package level. Therefore, even if the realization of the diamond surface pre-metallization, the traditional solid-phase powder metallurgy sintering method is impossible to achieve a strong combination of diamond and carcass material.
The last century, the late eighties, people began to explore the brazing technology for diamond tool production. The use of diamond surface plating some transitional elements (such as Ti, Cr, W, etc.), and with its chemical reaction surface carbide. Through this layer of carbide, diamond, binder, matrix three can be achieved by brazing solid metallurgical combination, in order to achieve the real diamond surface metallization, which diamond brazing principle. It can be seen from the published patent article that the technology can make the maximum cutting edge of diamonds to achieve particle size 2/3, tool life increased more than 3 times, while the conventional value of less than 1/3, allowing the blade can be used to achieve stability When the blade value to get. Therefore, the use of brazing technology is expected to achieve the matrix metal (solder) and the parent material - diamond steel matrix firmly between the combination.