Improvement of electroplating diamond tools
2015/9/3 13:41:53
The problems such as lack of control force, particle shedding and so on, which seriously affect the service life and efficiency of the tool. This article reviews at home and abroad in recent years developed improved properties of electroplated diamond tools, grouped into the following three categories: 1, improvement of coating matrix material performance, improve the support of diamond coating and binding; 2, by increasing the contact surface of the diamond and the matrix product, to eliminate the gap between diamond grits and plating layer; 3, surface modification of diamond particles, diamond and layer form a chemical bond. In this paper, a detailed description of various methods is described, and some potential methods are recommended, with a view to a comprehensive system for the reader to improve the method of electroplating diamond tools.
Because of the high hardness, high strength, high wear resistance and low coefficient of linear expansion coefficient, diamond tools are used to produce diamond tools for machining hard and brittle materials. The diamond tool is the electric deposition of the metal, and the loose diamond particles are consolidated in the plating layer, so that the diamond particles can be cut. The low temperature of diamond tools made by electroplating method is low, and it can avoid the heat loss of diamond, and the production process is simple, the equipment investment is little, the manufacturing cycle is short, the forming is convenient and can be repaired. Therefore, electroplated diamond products have various grinding wheel, grinding head, assorted file, cutting knife, dressing wheel, geological drill, reamer, both inside and outside the circular cutter, reamer, wire and other special tools, in the field of machinery, electronics, construction, drilling, optical glass processing industry to widely used [1-3].
At present, at home and abroad by electroplating method of preparing diamond tools, the main problems is coating metal matrix diamond particles and low bonding force, the use of diamond grains by force, easy to loose, resulting in short service life. The main reason of these phenomena is that when the diamond tools are used to prepare the diamond tools, the temperature is low, so that the surface of the diamond particles is not easy to be infiltrated by the general metal. In addition, by the influence of the plating process, the choice of the type of diamond tools is limited (limited to nickel, chromium and so on a few metals and its alloys), unlike the type of metal used by hot press.
In order to solve the above problems, people have adopted various measures to solve the binding force between diamond and metal. In this paper, the method of improving the properties of the electroplating diamond tools is introduced, and the method of improving the performance of the electroplating diamond tools is introduced.
1 improved matrix material
Of diamond tools electroplating coating on diamond support and interaction, known as the matrix or metal matrix, which determines the diamond particles could give full play to the role of cutting, the general requirements for it to meet the requirements of high hardness, high wear resistance and high toughness, so people first take into account the adopted to improve the performance of matrix material and the method improvement of diamond tools.
1.1 matrix metal alloy
Although the single coating (such as nickel) has a high strength, in particular, toughness, but the general hardness is lower, so people use the alloy coating.
1.1.1Ni-Co two element alloy coating [1-5]
Cobalt can not only improve the nickel metal strength (nickel cobalt alloy matrix compressive strength of 1600 MPa), and can improve the thermal properties of metal matrix, 800 Deg. C in Co Ni binary alloy matrix metal ultimate strength is 500MPa, but also improve the toughness of the metal matrix. Thus Co Ni binary alloy coating has become widely used matrix material, however sometimes Co Ni binary alloy coating hardness is still inadequate, in machining hard and abrasive strong materials, carcass consumption soon. And the Co Ni coating can only guarantee the high hardness and wear resistance, and a large amount of expensive metal cobalt increases the cost, only when the cobalt content is about 30%.
Mn 1.1.2Ni two alloy coating [6]
Manganese metal can improve the nickel matrix hardness, strength and wear resistance more than cobalt. Ni Mn matrix hardness Rockwell hardness than nickel cobalt (HRC) 10 degrees. Although the manganese content in the alloy is very few, but a great impact on carcass performance. Ni Mn matrix diamond bit hard strong abrasiveness formation drilling in, the average life expectancy and aging respectively than the Ni Co matrix diamond increased 55% and 30%, at the same time, Ni Mn matrix bit does not need high speed, high pressure, is conducive to the reduction of material consumption and reduce drilling cost. However, Mn Ni two alloy coating is brittle and easy to crack, so that the working layer is easy to crack.
Co Mn 1.1.3Ni three alloy coating [7]
Co Mn Ni three alloy coating has higher mechanical properties. Ni Co high hardness, brittleness and lower than Ni Mn, is in line with the requirements of the matrix of electroplated diamond products. Co Mn Ni three alloy plating production of stone tools than the use of Co Ni two alloy plating products more sharp, more durable, especially for hard stone, more can show the advantages of the. Because of saving a lot of expensive materials Co, Co Mn Ni three alloy plating cost is low. The mechanical properties of Co Mn Ni three alloy coating can be adjusted in a wide range to meet the needs of a wider range of applications. But in the Co Mn Ni three alloy plating, the plating liquid is complex and the stability is not easy to be controlled.
1.2 metal matrix composite
Composite coating is a special coating, which is formed by the co deposition method, one or several kinds of insoluble solid particles and fibers uniformly mixed into the metal coating. Because the composite coating is uniformly dispersed in a large number of solid particles, these hard particles, the slip between the grains will be a great hindrance to the role of gold