Diamond Abrasives Research Articles

Rapid grinding diamond film using a grinding wheel containing nickel-plated diamond abrasives based on mechanochemical effect

The excellent properties of diamond make it a highly promising substrate material for future sensors and semiconductor devices. The surface roughness of the substrate material directly impacts the performance of the devices. Therefore, achieving efficient and low-damage processing of diamonds is crucial. However, diamond has high hardness and chemical inertness, which makes it difficult to process. To tackle the above-mentioned problem, the diamond film was ground using a grinding wheel containing nickel (Ni)-plated diamond abrasives based on the mechanochemical effect. The maximum average material removal rate of the diamond film reached 2469 nm/min under a grinding pressure of 600 N at a speed of 600 rpm, and the minimum average surface roughness of the diamond film reached 3.93 nm under 500 N 600 rpm. The rapid reaction removal of the diamond film can be attributed to the catalytic effect of the Ni plating, inducing graphitization of the diamond film at the interface contact points under the generated high temperature during friction; subsequently, it can be removed under the mechanical action of the abrasives. This work has tremendous potential for the efficient and low-damage grinding of diamond films.

Two-dimensional structure evolution and formation of silicon carbides and diamonds in a nano-abrasion process

Structural phase transition is often expected when crystalline substrates with high mechanical strength are processed by diamond abrasion at nanoscale. The structural evolution and formation of 3 C-SiC substrates abraded by diamond were explored using molecular dynamics simulation. The evoluted structures were derived by analyzing bond length, bond angle and coordination changes of SiC and diamond abrasives before and after nano-abrasion. Our simulation results explicitly elucidate the stable, graphene-like two-dimensional (2D) structural evolution and formation from SiC and diamond crystalline. This generolized finding of 2D structural formation from three-dimensional (3D) materials in nano-abrasion may shed light on developing new preparation options to make graphene-like 2D-SiC, which is predicted to be a chemically and mechanically stable semicondcuting material with oustanding opto-electro properties.

Cutting force modeling and control of single crystal silicon using wire saw velocity reciprocation

Single crystal silicon wafers are often used as substrate material for integrated circuits. Often the wafer is cut by a wire with fixed abrasive diamond owning to a narrow kerf and a low cutting force. The cutting force changes during the process as the direction of wire movement continuously reverses (i.e., reciprocates), which may cause the wire saw to break, the wafer to collapse, and the wafer surface roughness to decrease even if the wire saw tension and the contact length between the wire and the wafer are fixed. In this work, a cutting force model including both normal and tangential forces was established to determine the relationship between the normal and tangential forces and the commanded wire speed. Separate controllers were developed to regulate both the normal force and the tangential force by adjusting the wire velocity. Experimental studies were conducted for wire saw processing of single crystal silicon wafers. Compared with a process using constant wire velocity, regulating the normal force can significantly reduce the processing time and the wafer surface roughness. The average improvements in processing time and wafer surface roughness are approximately 11% and 56%, respectively, when using normal force control, and approximately 29% and 30%, respectively, when using tangential force control. The results show that the normal and tangential forces can be well regulated during the machining process. In addition, the wafer surface roughness and machining time were lower in both experiments where the forces were regulated than in the experiment where a constant wire velocity was used. This paper demonstrates that the novel concept of regulating process forces in wire saw machining by adjusting the wire velocity can be used to optimize the cutting process of single crystal silicon, making the process more productive while decreasing the part roughness.

Mechanochemical grinding diamond film using titanium-coated diamond active abrasives prepared by vacuum micro-evaporation coating

The outstanding hardness and wear resistance of diamond materials pose significant challenges in their grinding processes for semiconductor substrate materials. To overcome this, a mechanochemical effect-based approach is used, which employs a grinding wheel comprising titanium (Ti)-coated diamond abrasives. A uniform Ti coating is vacuum-evaporated onto micrometer-scale diamond abrasives. The coating layer forms a diamond-TiC-Ti structure extending from the diamond matrix to the Ti coating direction. The material removal rate (MRR) of the DF is significantly increased as a result of the protruding active Ti coating on the diamond abrasives reacting with the DF at the interface contact locations. Increasing the grinding speed from 300 rpm to 700 rpm under a fixed grinding pressure of 300 N results in an MRR increment from 32 nm/min to 913 nm/min. Similarly, maintaining a grinding speed of 600 rpm while increasing the grinding pressure from 300 N to 600 N leads to an MRR increase from 388 nm/min to 1662 nm/min. The primary mechanism behind material removal is the reaction between the Ti coating and the DF, as well as the graphitization of the DF.

Novel designed mechanical-mechanochemical synergistic micro-grinding technology and compounded abrasive micro-grinding tools

The mechanical and mechanochemical synergistic micro-grinding technology was proposed for grinding hard and brittle materials, especially for fused silica micro parts in this work. Compounded abrasive micro-grinding tools with diamond abrasives on the outer layer and cerium oxide abrasives on the inner layer were designed and fabricated. Efficient grinding was initially achieved by mechanical processing of super hard abrasives, and then ultra-precision processing was obtained by mechanochemical process to remove surface or subsurface damage. This study firstly analyzed the contact model of single diamond abrasive particle and theoretically evaluated ground surface roughness. The mechanism of abrasive layer wear was investigated for accurate error compensation. The formulation of cerium oxide abrasive layer and its processing efficiency were further analyzed. The material removal mechanisms of fused silica during mechanochemical grinding were also studied. Results showed that the material removal rate was 1.924 μm/min and the surface roughness Ra was 0.248 μm after mechanical processing. Subsequently, the surface roughness Ra was improved to 38 nm after mechanochemical processing. The study indicates that this technique is a promising approach for high-efficiency and high-quality grinding of fused silica.

Degree of Filling of the Roughness Profile of the Surface Obtained by Diamond Abrasive Treatment as a Factor Affecting Its Bearing Capacity

Degree of Filling of the Roughness Profile of the Surface Obtained by Diamond Abrasive Treatment as a Factor Affecting Its Bearing Capacity

Mechanism of material removal on stainless steel through diamond abrasion: a molecular dynamics simulation study

Mechanism of material removal on stainless steel through diamond abrasion: a molecular dynamics simulation study

An internal cooling grinding wheel: From design to application

The cooling and lubrication conditions during the grinding process significantly impact the nickel-based superalloy's final service performance. The existing jet cooling and heat pipe technology can solve the heat conduction problem in the grinding process of superalloy. Still, managing cooling, lubrication, and chip removal are difficult. This paper describes the design and fabrication of a novel central fluid-through internal cooling slotted grinding wheel with an ordered grain pattern to improve the grinding machinability of a nickel-based superalloy. The pressurized grinding fluid was ejected into the grinding zone via the pipe and tool holder from the lower-end face of the inner cooling wheel. The structure of the grinding wheel was optimized using computational fluid dynamics (CFD). The flow field in the grinding area achieved the highest overall flow rate, distribution homogeneity, and effective exit flow when the internal flow channel had four through-holes. The exit for the inner runner is located at the abrasive edge and diamond staggered pattern. Single-layer brazing was used to create cubic boron nitride (CBN) abrasive rings with various abrasive patterns. The internal cooling wheel matrix and various components were prepared according to the optimized grinding wheel geometry model. A grinding test bench was built to conduct an experimental study of grinding the nickel-based alloy GH4169. The results show that, under the same conditions, a diamond-shaped staggered pattern obtains lower grinding temperature, lower surface roughness, better surface morphology, and more significant residual compressive stress distribution than an abrasive cluster diagonal circular staggered pattern or disordered pattern. The average effective flow rate calculated by CFD is increased by 42.3% when compared to the disordered pattern. In the experiment, compared to the disordered arrangement, with the increase of grinding wheel’s rotating speed and coolant pressure, the average grinding temperature of abrasive grain with diamond-interleaved arrangement decreases by 58.2% and 51.7% respectively, and its surface hardening degree decreases by 11.1% and 11.7% respectively.

Influence of Abrasion on Corrosive Behavior of a Supermartensitic Stainless Steel in Saline Medium

Abstract Supermartensitic stainless steels, with moderate wear and corrosion resistance, are commonly used in the petroleum and gas industry. A setup configured with a potentiostat and a tribometer was developed to study tribocorrosion behavior of a supermartensitic stainless steel. The electrochemical evaluation indicated that under abrasion, the breakdown potential shifted from 73 V toward lower values, reaching −76 mV(Ag/AgCl) by using larger particles. Using the smallest particles, the breakdown potential was the highest. Because of the synergetic effect of wear and corrosion, the concentration of pits was higher with rubbing, but the pit growth was inhibited. The effects of particle size on wear and corrosion were evaluated using diamond particles with a size range of 10–20 μm, 30–40 μm, 40–60 μm, and 140–170 μm. The smallest particles promoted the highest pit growth inhibition and the highest breakdown potential but also the highest passivation current density. The larger abrasive diamond particles decreased the breakdown potential of the supermartensitic stainless steel in a saline solution.

Effect of catalyst composition on growth and crack defects of large diamond single crystal under high temperature and pressure

Under the condition of 5.6 GPa and 1250–1450 ℃, the diamond single crystals are synthesized in a cubic anvil high-pressure and high-temperature apparatus. High-purity FeNiCo solvents or NiMnCo solvents are chosen as the catalysts. High-purity (99.99%) graphite powders selected as a carbon source. High-quality abrasive grade diamond single crystals with relatively developed (100) or (111) crystal planes are used as crystal seeds. The effects of catalyst composition on crack defects in diamond single crystals are studied carefully. Firstly, using FeNiCo and NiMnCo catalysts respectively, we carry out the diamond single crystal growth experiments. It is found that under the same crystal growth condition, the probability of crystal crack defects in diamond single crystals grown with FeNiCo catalyst is significantly higher than that of crystals grown with NiMnCo catalyst. We believe that this is related to the high viscosity, poor fluidity of FeNiCo catalyst melt, and the large specific surface area of the crystal during growth, which leads to its high requirements for the stability of growth conditions. Secondly, the relationship between the growth time and the limit weight gain speed of the diamond single crystal synthesized, respectively, by FeNiCo catalyst and NiMnCo catalyst are investigated. The results are shown below. 1) The limiting growth rate of diamond single crystal increases with the growth time going by. 2) In the same growth time, the limit growth rate of diamond crystal grown with NiMnCo catalyst is higher than that of diamond crystal grown with NiMnCo catalyst. Thirdly, by scanning electron microscopy (SEM), we calibrate the surface morphology of the synthesized diamond single crystal. The test results show that the diamond single crystal has a high surface flatness. Even for the crystals with crack defects in the interior, the surface flatness is still good. However, Fourier transform infrared (FTIR) measurements show that the nitrogen impurity content of diamond crystal grown by FeNiCo catalyst with crack defect is about 3.66×10<sup>–4</sup>. The content of nitrogen impurity in the crystal grown by NiMnCo catalyst without crack defect is about 4.88×10<sup>–4</sup>. The results show that there is no direct correlation between nitrogen impurity content and crack defects in diamond crystal.

The effect of heat flow from friction forces on the surface of the billets

In modern mechanical engineering, technical ceramics is finding increasing use. It has unique anti-corrosion properties and resistance to high temperatures. In most cases, the processing modes and characteristics of abrasive (diamond) wheels are selected experimentally, since there is no modeling of processing processes in the public domain. The article presents an experimental study of the surface of dissimilar materials under the influence of heat flow from the friction force of grinding wheel grains. The comparison of calculated indicators and the results of laboratory studies is given. It is concluded that the heat flow from the friction forces of the grains on the material does not cause the destruction of the polished surface. It is also shown that the flow density due to varying modes of grinding

The interfacial reaction between diamond (100) surface and CuNi-based filler alloys containing Cr by first-principles calculations

Brazed diamond tools have the advantages of high holding strength for diamond abrasives, superior grinding performance, formability, etc. The elements used commonly in filler alloys such as Cr, Cu, and Ni have an important impact on the interfacial bond strength and diamond thermal damage. In this work, the interactions between Cu, Ni, and Cr of the filler alloy and the diamond (100) surface were investigated using first-principles calculations. The results indicated that the adsorption energy of Cu adsorbed on the diamond (100) surface was low, suggesting that C atoms are extremely difficult to dissolve into Cu-based filler alloys, which makes Cu-based filler alloys less wettable with diamond. While the adsorption energy of Ni adsorbed on the diamond (100) surface was greater, which may form Ni 3 C weak carbide. Therefore, Ni-based filler alloys are usually wettable with diamonds. However, Ni 3 C of poor stability may decompose C atoms at the interface, which may lead to greater corrosion of diamonds. The adsorption energy of Cr adsorbed on the diamond (100) surface was the highest among Cu, Ni, and Cr, while the co-adsorption of Cr and C can grow into stable carbides. With the extension of time, the carbides can grow to form continuous layers of carbides. The results are generally consistent with the experimental results. • Analysis of graphitization on diamond surfaces using first-principles calculations. • The co-adsorption and deposition processes of Cr and C were investigated, which provided the conditions for the formation of chromium carbides. • Interfacial reaction processes, such as C precipitation and carbides nucleation growth, were investigated at the atomic level using first-principles calculations.

Optimal Dressing of Diamond Abrasive Wheels with Metallic Binder

Optimal Dressing of Diamond Abrasive Wheels with Metallic Binder

Structural design and mechanical properties of porous structured diamond abrasive tool by selective laser melting

Additive manufacturing is an important and promising way to realize the structural-functional integration of diamond abrasive tools. In the presented study, the porous diamond grinding heads with different pore structure and porosity were designed and fabricated by selective laser melting (SLM). By analyzing the stress distribution of overall structures and pore units, the 50 %-porosity square-pore structure with lowest stress concentration degree was optimized. The porous composite samples had good SLM formability, including good integrity and connectivity of pore units, and the diamond abrasives were evenly distributed and exhibited good retention and protrusion height. The high retention was attributed to the multiple interfacial system composed of carbide layer and solid solution strengthening layer. Compared with other porous samples, the 50 %-porosity square-pore structured sample with frame supporting unit and uniform stress distribution showed high deformation resistance of 430 MPa in yield strength and energy absorption capacity of 56.4 MJ/m3, which well verified the simulation results. The wear and grinding tests showed that the sharpness and self-sharpening ability of porous samples were significantly superior to the full-dense sample, and the grinding ratio increased with the increasing of the porosity.

Chemical reaction on silicon carbide wafer (0 0 0 1 and 0 0 0 −1) with water molecules in nanoscale polishing

Chemical reactions occurring in atomic level are of importance for the nano-manufacturing process. The tribochemistry mechanism for the ultra-precision polishing of 6H-SiC wafers with only deionized water used as the coolant is expounded. Both Si face and C face of 6H-SiC wafers chemically react with water molecules during the interfacial friction and then form silicon dioxide. The silicon dioxide generated on the Si face is crystallized, while that on the C face is amorphous. Reactive molecular dynamics simulations further confirm the findings of the experiments and indicate that the interfacial friction with the diamond abrasives facilitate the destruction of the lattice structure, which promotes the reaction between 6H-SiC and H2O molecules. The reveal of the chemical mechanism for the nanoscale polishing on SiC wafers may guide and optimize the polishing process, thereby improving the nano-machining efficiency.

Quantitative investigation of thermal evolution and graphitisation of diamond abrasives in powder bed fusion-laser beam of metal-matrix diamond composites

ABSTRACT Preventing the thermal damage of diamond abrasives is the major challenge of diamond composites in the field of super-hard tools by laser additive manufacturing. In the presented work, we established a quantitative framework to accurately evaluate the thermal damage behaviour and the relevant microstructure-performance characteristics, by using CuSn10-diamond composite by powder bed fusion-laser beam (PBF-LB). By simulating the thermal history of diamond in the molten pool and microstructure characterisation, the critical temperature of 1491.6°C of diamond graphitisation was obtained. Below the critical temperature, the composite with no diamond-graphitisation exhibited abrasive wear and wear loss rate below 0.01%. The increasing temperature led to the aggravation of graphitisation, which ID: IG value changed from 2.00 to 0.57 with the temperature increasing from 1491.6°C to 1896.1°C, resulting in wear mechanism changing from adhesive wear to three-body abrasion, with the wear loss rate from 0.01% to 0.73%. Integrating the results of simulation, microstructures and wear properties, the graphitisation threshold of diamond in PBF-LB was revealed and the quantitative relationship of ‘PBF-LB parameters - Temperature - Graphitisation degree - Wear resistance’ of the metal-matrix diamond composites was established.

Effects of three-body diamond abrasive polishing on silicon carbide surface based on molecular dynamics simulations

Recently, SiC has gained considerable interest owing to its avant-garde nature and relevance in future applications. Molecular dynamics simulation was performed to investigate nanopolishing of three-body diamond abrasives on workpieces that had undergone cluster deposition and annealing processes. The coordination number, temperature, atomic distribution, kinetic energy, friction coefficient, crystallization, and average height of the workpiece were determined. Further, the effects of different polishing depths and polishing speeds on the physical properties of the workpiece were determined. Results show that polishing depth considerably affects the coordination number, surface morphology, friction coefficient, crystallization, and temperature of the workpiece. The surface of the workpiece was polished while maintaining the crystallization rate at a polishing depth of 20 Å. With an increase in the polishing rate, the coefficient of friction decreased, the temperature of the workpiece increased, and the polishing trajectory became clearer, with a better crystallization at 1 Å/ps.

A novel dry processing technique to construct a high-performance superfine diamond grinding wheel with thermal and material characterizations

A novel dry process that prepared in mixing with a pore-forming agent employs a single batch process in production of grinding wheels with the advantage without using resin liquid as an additive binder. The agglomeration of a pore-forming agent can be avoided due to no dressing agent mixing with the superfine diamond abrasives and binders. Bulk mass production can still ensure to fulfill the excellent homogeneity in mixing cross the entire grinding wheel. Therefore, an uneven mixing caused by mixing errors and human factors can be minimized. The grinding wheel can reach an ultrahigh porosity (~82 %) at a lower sintering temperature of 620 °C. Low-temperature sintering can effectively reduce the carbon footprint. A thermogravimetric-differential scanning calorimeter (TG-DSC) was used to determine the thermal properties of superfine frits. Further characterization of ultrafine binders by an optical non-contact dilatometry is utilized to set-up a protocol sintering plan of grinding wheels. Microstructure from scanning electron microscope (SEM) measurement on grinding wheel presents a uniform large pore structure which offers a benefit to wafer surface removal and less scorching during grinding. Atomic force microscopy (AFM), laser scanning digital microscope (LSCM) and SEM results revealed that the ground silicon (Si) wafer had a low surface roughness (~6 nm), without deep scratches, and with a low damaged layer (~0.7 μm) respectively. The wear test on grinding wheels demonstrates it is very cost effective to use a dry processing wheel. This work provides a new method for grinding Si wafers with a new type of wheel being developed by a novel dry superfine diamond grinding technique in a manufacturing process. It is realized that the use of a dry grinding process can save part of chemical polishing process (CMP) and effectively reduces the polishing time.

The effect of ceramic surface structure modification method on the ignition and combustion behavior of non-metallized and metallized gel fuel particles exposed to conductive heating

The study explores the effect of roughness characteristics of ceramic surfaces processed by diamond abrasives (ground and polished) and laser radiation on the consistent patterns and characteristics of the ignition and combustion of non-metallized and metallized gel fuel (GF) particles based on oil-filled cryogels exposed to conductive heating. Ceramics were produced from SiC F1200 powder using spark plasma sintering. It was established that when combustible liquid droplets in a normal state, as well as metallized and non-metallized GF particles are ignited and burned on a ceramic surface, the ignition delay times can be controlled by the characteristics of the heating surface roughness. Laser surface treatment of ceramics was shown to be a high-potential technique to control the ignition delay times of combustible liquid droplets (±48 %), as well as metallized and non-metallized GF particles (±35 %). A reduction in the ignition delay times of liquid fuels, when using laser surface treatment of ceramics, calls for developed, multi-level roughness with Sdr more than 6.3 %. To decrease the ignition delay times of GF on a ceramic surface by using laser treatment, it is necessary to create a texture with roughness parameters Sdr, Sq, Sz close to the respective characteristics of a polished (molecularly-smooth) heating surface. Evidence was provided that laser surface treatment of ceramics is more promising than mechanical processing using diamond abrasives, which is the most common method currently used in mechanical engineering. This is explained by the fact that laser surface treatment of ceramics creates conditions for enhancing the dispersion of GF melt droplets when ignited, as well as reduces the burnout time by creating a layered multimodal texture of the heating surface, characterized by more developed roughness as compared with the texture resulting from the mechanical processing by means of diamond abrasives.

On the Analysis of the Estimate of Energy Expenditures in the Diamond Abrasive Treatment by Wheels from Superhard Materials

On the Analysis of the Estimate of Energy Expenditures in the Diamond Abrasive Treatment by Wheels from Superhard Materials