The Significance and Principle of Surface Metallization of Diamond Abrasive Powder

Since ancient times, diamonds have been regarded as an extremely precious decoration. However, with the development of modern industrial technology, the unique mechanical, thermal and electrical properties of diamond have gradually been unearthed, turning it from a mere handicraft into an important industrial raw material.

Excellent hardness and wear resistance, so that tools and abrasives made of diamond abrasives are widely used in machinery, building materials, optical instruments, metallurgy, electronics, petroleum and other fields. For example, all kinds of grinding wheels, grinding wheels, emery cloths, and abrasive pastes made of synthetic diamond powder are quite skilled in mechanical processing, which can improve the smoothness and dimensional precision of mechanical products.

Ⅰ. The significance of surface metallization of diamond abrasives

However, no matter how good the diamond itself is, it will be difficult to sing alone-this is because the particle size of artificial diamond particles is relatively small, and almost all uses require crystals to be bonded to the substrate or implanted in it. However, diamond has high interface energy with most metals, ceramics, etc., so the bonding force between diamond and the matrix is poor, and it is easy to cause the early fall of the diamond.

At present, diamond sawing tools are mostly produced by powder metallurgy, and the sintering temperature is generally as high as 900 ℃. When diamond is heated to about 700 ℃ in air, it will lose weight due to oxidation and decrease in compression resistance. Diamond will be graphitized above 1000 ℃, thus Greatly affect the use effect of diamond.

Therefore, how to improve the oxidation resistance of super grit abrasives and prevent graphitization is the key factor to improve the service life of diamond tools in the high temperature field.

At present, the method of plating metal on the diamond surface is generally used to reduce the interface energy between the diamond and the matrix, and a stable chemical metallurgical bond is formed through the layer of metal and the bonding agent. The binding agent mainly plays the following important roles.

1. Disperse and hold diamond particles;

2. Make the diamond particles exposed to a certain extent;

3. Prevent the diamond particles from falling off prematurely;

4. Quickly dissipate the heat generated during the working process to withstand and disperse the impact generated by the diamond work.

Ⅱ. The principle of surface metallization of diamond abrasives

Diamond surface metallization is the use of surface treatment technology to coat the surface of diamond particles with metal, so that the surface has metal or metal-like properties. The metalized surface is composed of three layers of materials, from the outside to the inside, as follows:

The first layer is a metal layer, which can give the diamond surface many new characteristics, such as excellent thermal and electrical conductivity;

The second layer is an alloyed layer, which is composed of carbide and metal structures;

The third layer is a carbide layer, generally a few hundred to thousands of angstroms (Å) thick, which can be firmly attached to the surface of the diamond grit powder product. It is the key to the metalization of the diamond particle surface. It is generally composed of a good wettability with diamond. Metal, such as Ti, W, Cr, V, etc., these elements can react with diamond at high temperatures to form stable carbides. It not only has a good chemical bond with diamond, but also can isolate it from direct contact with oxygen to prevent it from being oxidized at high temperatures.