CN-118268940-B - Photochemical reaction and shear thickening composite polishing method applicable to diamond workpiece

CN118268940BCN 118268940 BCN118268940 BCN 118268940BCN-118268940-B

Abstract

The invention discloses a photochemical reaction and shear thickening compound polishing method suitable for diamond workpieces, which is characterized in that a specific shear thickening polishing solution is used for processing the diamond workpieces, ultraviolet light is continuously irradiated to the polishing solution during polishing, photocatalyst micro powder in the polishing solution absorbs ultraviolet light energy, photo-generated holes form hydroxyl free radicals, on one hand, the hydroxyl free radicals are combined with Si dangling bonds on the surface of nano silicon dioxide to form-Si-OH groups, on the other hand, the hydroxyl free radicals in the shear thickening polishing solution are contacted with the rough surface of the workpieces to form a large number of-OH functional groups on the surface of the workpieces, during polishing, the workpiece surface and the shear thickening polishing solution are rubbed with each other to enable the local temperature of the shear thickening polishing solution to rise, so that condensation reaction is promoted to form C-O-Si chemical bonds, and then under the action of strong shearing force, the C-C back bonds on the surface of the diamond workpieces are broken, so that the C-O-Si chemical bonds on the surface of the diamond workpieces are removed, and the purpose of high-efficiency and high-quality polishing is achieved.

Inventors

LV BINGHAI
KE MINGFENG
WANG JIAHUAN
SHAO LANYING
ZHOU YU

Assignees

浙江工业大学

Dates

Publication Date: 20260505
Application Date: 20240328

Claims (10)

1. The photochemical reaction and shear thickening composite polishing method suitable for the diamond workpiece is characterized by comprising the following steps of: according to the method, a shearing thickening polishing device is utilized to polish a diamond workpiece, and during polishing, the diamond workpiece and the shearing thickening polishing liquid in a polishing groove have relative shearing action, so that material removal is realized; The polishing method comprises the steps of preparing a polishing solution, namely, a shear thickening polishing solution, wherein the polishing solution comprises hydrogen peroxide, nano silicon dioxide and photocatalyst micro powder, ultraviolet light is irradiated to the shear thickening polishing solution in the polishing process, the photocatalyst micro powder in the polishing solution absorbs energy of the ultraviolet light, electrons are excited to be carried out on a valence band to a conduction band, free electrons and holes are formed, the holes have strong oxidizing property, H 2 O or H 2 O 2 adsorbed on the surface of the photocatalyst micro powder is catalyzed to generate hydroxyl free radicals with strong oxidizing property, one part of the hydroxyl free radicals and Si suspension bonds on the surface of the nano silicon dioxide are combined to form-Si-OH groups, the surface of the nano silicon dioxide is covered and modified to be super-hydrophilic, the other part of the hydroxyl free radicals and C suspension bonds on the surface of the diamond are combined to form-OH functional groups, friction between a diamond workpiece and the shear thickening polishing solution in the polishing process causes the system to heat, the-OH functional groups on the surface of the diamond workpiece and the-Si-OH groups on the surface of the nano silicon dioxide are subjected to generate condensation reaction, and the strong shearing force on the diamond workpiece breaks the C-C bond, so that the C-O-Si bond on the surface of the diamond workpiece is removed under the condition that the friction effect is removed under the friction effect of the friction and the friction effect.
2. The method of claim 1, wherein the polishing tank is made of transparent material, and the ultraviolet light source is disposed below or beside the bottom end of the polishing tank.
3. The method for polishing diamond workpiece by photochemical reaction and shear thickening according to claim 2, wherein the ultraviolet light is short-wave ultraviolet light with a wavelength of 150-450nm, the ultraviolet intensity is 1000-3000mW/cm 2 , and the distance between the ultraviolet light source and the bottom end of the polishing groove is 2-5mm.
4. The photochemical reaction and shear thickening composite polishing method for diamond workpieces according to claim 3, wherein the mass fraction of hydrogen peroxide in the shear thickening polishing solution is 1% -3%, the mass fraction of nano silicon dioxide in the polishing solution is 45% -55%, and the mass fraction of photocatalyst micro powder in the polishing solution is 2% -4%.
5. The method for performing photochemical reaction and shear thickening composite polishing on a diamond workpiece according to claim 1, wherein the shear thickening polishing solution is further provided with an adsorption type corrosion inhibitor, and the adsorption type corrosion inhibitor acts on the surface of the diamond workpiece to form a corrosion inhibition film during polishing, so that the rough peak of a base material is reduced, the surface tends to be stable, the thickness of the corrosion inhibition film tends to be stable along with continuous polishing of the diamond workpiece, and the surface damage of nano silicon dioxide and photocatalyst micro powder to the base material of the diamond workpiece is reduced.
6. The method for performing photochemical reaction and shear thickening composite polishing on a diamond workpiece according to claim 5, wherein the mass ratio of the hydrogen peroxide reagent to the adsorption type corrosion inhibitor in the shear thickening polishing solution is 3-5:1.
7. The method for polishing diamond workpiece by combining photochemical reaction and shear thickening according to claim 1, wherein the photocatalyst micro powder is nano zinc oxide.
8. The method of claim 1, wherein the diamond workpiece is a part made of polycrystalline diamond, single crystal diamond or diamond coating material.
9. The method for polishing a diamond workpiece by combining photochemical reaction and shear thickening according to claim 8, wherein the diamond workpiece is a diamond cutter, and during polishing, a cutter handle of the diamond cutter is inserted into a corresponding clamp hole at the lower end of a workpiece shaft to clamp the diamond workpiece, a machined surface is exposed, the height is controlled to enable the machined surface to be immersed in the shear thickening polishing liquid, the rotation of the workpiece shaft is utilized to drive the diamond cutter to rotate, and meanwhile, a polishing groove rotates in the opposite direction.
10. The method of claim 9, wherein the rotation speed of the polishing groove is 80-110rpm and the rotation speed of the workpiece shaft is 2-10rpm.

Description

Photochemical reaction and shear thickening composite polishing method applicable to diamond workpiece Technical Field The invention relates to the technical field of ultra-precise polishing, in particular to a photochemical reaction and shear thickening compound polishing method applicable to diamond workpieces. Background Due to its unique physical and chemical properties, diamond has the advantages of high hardness, high strength, good wear resistance, good thermal conductivity, excellent chemical stability and the like, is widely applied to various fields of machining, semiconductor materials, electronic and electric appliance manufacturing and the like, and has become one of the most promising materials in the modern industry along with the rapid development of ultra-precise polishing processing and semiconductor technology. However, it is these excellent properties of diamond that make diamond an extremely difficult material to process, and conventional diamond work polishing methods mainly include laser melting, mechanical polishing, and chemical mechanical polishing. The laser melting method has high polishing efficiency, can efficiently remove diamond surface materials, has low polishing precision, is easy to form a thermal damage layer on the diamond surface/subsurface, is easy to bond and gasify residual impurities on the processed surface, affects the performance of the diamond materials, has high price of laser melting equipment, has high production cost, low production cost, high flexibility and high polishing speed, can only perform rough polishing, can not meet the requirements of ultra-precise workpieces, is easy to cause high damage (defects and lattice distortion) of the diamond and polishing wheel, and has the advantages that the chemical mechanical polishing method can obtain smooth surfaces, ultra-low surface/subsurface damage, large polishing area and low cost, can only polish planar workpieces, is not suitable for diamond workpieces with complex shapes, is not friendly to the environment, has very low MRR value and needs high temperature in the processing process. The shearing thickening polishing method is a novel polishing technology which is suitable for polishing complex curved surfaces and developed in recent years, and during polishing, the relative motion between a workpiece and polishing liquid enables the polishing liquid with shearing thickening characteristics to generate a shearing thickening effect, the viscosity is rapidly increased, and the holding force of abrasive particles is increased, so that a flexible 'fixed grinding tool' which is attached to the surface of the workpiece is formed in a processing area, and high-quality polishing processing of the complex curved surfaces can be realized. However, for diamond workpieces (such as diamond cutters), the high hardness and the high wear resistance of the diamond workpieces make the surface materials of the diamond workpieces extremely difficult to remove, and the ordinary shear thickening polishing process is difficult to effectively remove the micro-peaks on the surfaces of the diamond workpieces, so that the high-efficiency and high-precision polishing processing of the diamond workpieces cannot be realized. The strong oxidant added in the shear thickening polishing solution is beneficial to improving the material removal efficiency, but can damage and oxidize other parts of the diamond workpiece, and the polishing consistency of the surface interconnection heterogeneous surface (the interconnection surface of the diamond material and the matrix material) of the workpiece can be reduced under the condition of not processing. Disclosure of Invention In order to overcome the defects in the prior art, the invention provides a photochemical reaction and shear thickening composite polishing method, wherein the shear thickening polishing solution used in the method contains specific components, ultraviolet light is used for continuously irradiating the polishing solution during polishing, and the photochemical reaction, the tribochemical reaction and the shear thickening effect cooperate in the polishing process to realize the efficient and high-quality polishing processing of the surface of the diamond workpiece. The invention provides the following technical scheme: The method is suitable for photochemical reaction and shear thickening composite polishing of diamond workpieces, and utilizes a shear thickening polishing device to polish the diamond workpieces, when the shearing thickening polishing device is used for polishing, the relative shearing action exists between the diamond workpieces and a shear thickening polishing solution in a polishing groove to remove materials, the shear thickening polishing solution contains hydrogen peroxide, nano silicon dioxide and photocatalyst micro powder, ultraviolet light is irradiated into the shear thickening polishing solution in the polishing process, the photocatalyst micro