Effect Of Abrasive Concentration Research Articles

Effect of Abrasive Concentration on Impact Performance of Abrasive Water Jet Crushing Concrete

It has been found that the impact performance of water jets can be changed by its properties, which include pressure, additive, and mode of jet. Thus, an abrasive water jet (AWJ) has been developed as a new method. However, there is little research on the effect of abrasive concentration on the impact performance of abrasive jets. Thus, the SPH method is used to establish an abrasive water jet crushing concrete model to study the effect of abrasive concentration on the impact force, concrete internal energy, abrasive particle distribution, crushing depth, and damage and crushing efficiencies under different concrete compressive strengths and abrasive densities. The results indicate that there is little effect of the abrasive concentration on the peak impact force under different compressive strengths and abrasive densities, while the mean impact force tends to increase linearly with the abrasive concentration. The internal energy of the concrete increases stepwise with the abrasive concentration under different compressive strengths and abrasive densities. The concentration of 10%∼20% is the rapid increasing stage. The crushing depth and damage efficiencies are all maximum at a concentration of 20% under different compressive strengths and abrasive densities. After the concrete was impacted by the water from the water jet, it is divided into rebounding particles and intrusive particles. The more the intrusive particles, the easier the concrete to be crushed and damaged.

Rapid fabrication of a silicon modification layer on silicon carbide substrate.

We develop a kind of magnetorheological (MR) polishing fluid for the fabrication of a silicon modification layer on a silicon carbide substrate based on chemical theory and actual polishing requirements. The effect of abrasive concentration in MR polishing fluid on material removal rate and removal function shape is investigated. We conclude that material removal rate will increase and tends to peak value as the abrasive concentration increases to 0.3 vol. %, and the removal function profile will become steep, which is a disadvantage to surface frequency error removal at the same time. The removal function stability is also studied and the results show that the prepared MR polishing fluid can satisfy actual fabrication requirements. An aspheric reflective mirror of silicon carbide modified by silicon is well polished by combining magnetorheological finishing (MRF) using two types of MR polishing fluid and computer controlled optical surfacing (CCOS) processes. The surface accuracy root mean square (RMS) is improved from 0.087λ(λ=632.8 nm) initially to 0.020λ(λ=632.8 nm) in 5.5 h total and the tool marks resulting from MRF are negligible. The PSD analysis results also shows that the final surface is uniformly polished.

Effect of Abrasive Concentration on Chemical Mechanical Polishing of Sapphire**Supported by the National Major Scientific and Technological Special Project during the Twelfth Five-year Plan Period under Grant No 2011ZX02704, the National Natural Science Foundation of China under Grant No 51205387, and the Science and Technology Commission of Shanghai under Grant Nos 11nm0500300 and 14XD1425300.

Effects of abrasive concentration on material removal rate (MRR) and surface quality in the chemical mechanical polishing (CMP) of light-emitting diode sapphire substrates are investigated. Experimental results show that the MRR increases linearly with the abrasive concentration, while the rms roughness decreases with the increasing abrasive concentration. In addition, the in situ coefficient of friction (COF) is also conducted during the sapphire polishing process. The results present that COF increases sharply with the abrasive concentration up to 20 wt% and then shows a slight decrease from 20 wt% to 40 wt%. Temperature is a product of the friction force that is proportional to COF, which is an indicator for the mechanism of the sapphire CMP.

Analysis of removal mechanism on oxide CMP using mixed abrasive slurry

Mixed abrasive slurry (MAS) is one of the non-traditional slurries with more than two different sizes, shapes or materials of abrasives which are to improve a chemical mechanical polishing (CMP) performance such as a removal rate. This paper focuses on the MAS mixed with two different sized abrasives and controlled by mixing ratio. Hybrid effect of the MAS was investigated from the removal mechanism of the mixed abrasives on oxide film. Experiments have been implemented with a 4-inch wafer with silicon dioxide film and KOH-based colloidal silica slurries. The slurry has two different sizes, 30 nm and 70 nm, with concentration of 1~30 wt%. The effects of abrasive concentration and mixing ratio were investigated in the oxide CMP in order to achieve high removal rate. During the oxide CMP with the MAS, the contact condition of abrasives was changed by mixing ratio. Through the experiment, it could be seen that two-body and three-body abrasions occur in mixed abrasive slurry according to the particle concentration. Finally, we could see that the proper ratio to achieve high removal rate was 2:1 (D30:D70) since most of the abrasives were active in material removal and carried out two-body abrasion.

Feature-Scale Simulations of Particulate Slurry Flows in Chemical Mechanical Polishing by Smoothed Particle Hydrodynamics

AbstractIn this paper, the mechanisms of material removal in chemical mechanical polishing (CMP) processes are investigated in detail by the smoothed particle hydrodynamics (SPH) method. The feature-scale behaviours of slurry flow, rough pad, wafer defects, moving solid boundaries, slurry-abrasive interactions, and abrasive collisions are modelled and simulated. Compared with previous work on CMP simulations, our simulations incorporate more realistic physical aspects of the CMP process, especially the effect of abrasive concentration in the slurry flows. The preliminary results on slurry flow in CMP provide microscopic insights on the experimental data of the relation between the removal rate and abrasive concentration and demonstrate that SPH is a suitable method for the research of CMP processes.

2609 電気泳動法によるCMG砥石の開発とその性能評価(S74-1 砥粒加工(1),S74 砥粒加工)

Aiming toward the complete conversion to fixed abrasive process of single crystal silicon wafer, the Chemo-mechanical grinding (CMG) process which positively adopts chemical action to grinding process was proposed. Development and its appraisal experiment of the CMG wheel with EPD (electrophoretic deposition) were done in this research. Ceria (CeO2) abrasive and sodium alginate (used as binder) were used to grow pellets and the pellets were allocated peripherally to form CMG wheel. The effects of abrasive concentration, binder concentration ratio and applied voltage on the CMG wheel growth were investigated. The property of produced pellets and grinding performance of CMG wheel were experimentally studied.