Metal coating film, also known as chemical coating film, that is, before the diamond inlay, first in its surface coated with a layer of metal film, into a diamond with a metal coating. The purpose of metal coating is to improve the bonding property of diamond matrix and the temperature stability of diamond.
The coated metal layer can prevent the oxidizing medium from contacting the diamond and slow down the process of the diamond being graphitized at high temperature. This metal layer can also fill the gaps on the surface of the diamond, so as to improve the strength of the diamond. At present, domestic and foreign researches on coating materials and processes have been carried out. The coating metals used include nickel, chromium and cobalt, etc., and the remaining coating methods include chemical method and metallurgy method, etc. The coating thickness is generally 1.0~15ym. The test shows that the life of coated diamond bit can be increased by 10%, and the drilling speed can be increased by 5%~7%.
Vacuum coating is an important aspect in the field of vacuum application. Based on vacuum technology, it USES physical or chemical methods and absorbs a series of new technologies, such as electron beam, molecular beam, ion beam, etc., radio frequency and magnetic control, to provide a new process for film preparation for scientific research and practical production. Simply put, the method of vaporizing or sputtering a metal, alloy or compound in a vacuum to make it solidify and deposit on the coated object (called substrate, substrate or matrix) is called vacuum coating.
As is known to all, the surface of some materials, as long as the coating of a thin film, can make the material has many new, good physical and chemical properties. In the 1970s, the main methods of coating on the surface of objects are electroplating and electroless plating. The former is through electrification, electrolyte electrolysis, electrolyte ion plating as another electrode on the surface of the substrate, so the condition of this coating, the substrate must be a good conductor of electricity, and the thickness of the film is difficult to control. The latter is the use of chemical reduction method, must be made up of membrane into a solution, and can quickly participate in the reduction reaction, this coating method is not only the bonding strength of the film is poor, and coating is neither uniform nor easy to control, but also produce a lot of waste liquid, causing serious pollution. Therefore, these two methods, which are called wet coating process, are very limited.
Vacuum coating is a new kind of coating technology developed relative to the wet coating method, which is usually called dry coating technology.
