Papers by Keyword: Diamond Abrasive

Abstract: Shear-thickening polishing (STP) technology was used on ultraprecision machining of Si₃N₄ ceramics. The STP slurry with diamond abrasives was prepared for STP process and its rheological property was studied. The polishing performance of Si₃N₄ ceramics with STP was analyzed. Results show that STP slurry with diamond abrasives exhibits non-Newtonian power-law fluid characteristics with shear-thickening effect. As using STP slurry with abrasive particle size of 0.2 μm, the material removal rate changed from 4.22 to 4.05 μm/h after 60 mins ́ polishing; and decreased from 3.88 to 3.75 μm/h after 120 mins ́ polishing. The average surface roughness reduced from R_a 107.2 to R_a 6.5 nm after 120 mins ́ polishing.

Abstract: Diamond abrasive coated wires are core tools for precision multi-wire sawing of mono-crystal ingots for substrate manufacturing, especially for hard materials applications such as SiC, GaN, sapphire and silicon. However, repeated contact by reciprocation motion of wire makes it difficult to design optimized utilization of diamond wires since it makes temporal change in cutting performance due to gradual wear of abrasives. In this paper, the cutting performance of wires are examined based on experimental results with wires having different concentration. The results indicated that the concentration of diamond abrasives have strong relationship with cutting performance and wires with low concentration showed higher material removal characteristics.

Abstract: In this paper, diamond abrasive SG films were prepared by means of sol-gel technology for polishing single-crystal SiC wafers. The effects of machining parameters on processing quality including pressure, rotating speed and polishing time were investigated, respectively. The results indicated that the surface roughness decreased with increasing polishing time. While for pressure and rotating speed, there were inflections existing. Polishing SiC wafer under optimized machining parameters, an ultra smooth surface with the roughness of 3.7 nm could be achieved using 40 μm diamond grits.

Abstract: In this paper, according to the slurry ingredients obtained by former research, the influences of the chemical mechanical polishing (CMP) process parameters, such as the rotational velocity of the platen and the carrier, the polishing pressure and the abrasive size on the material removal rate (MRR) and surface roughness Ra have been studied in CMP SiC crystal substrate (0001) C and (0001) Si surface based on the diamond abrasive. The research results show that the material removal rate changes with the change of the abrasive size, the rotational velocity of the platen and the polishing pressure significantly, but the maximum of MRR can be obtained at a certain rotational velocity of platen, abrasive size and polishing pressure. The influence of the abrasive size, the platen velocity, the carrier velocity and the polishing pressure on surface roughness is no significant. Under the same conditions, the MRR of CMP the Si surface is larger than that of the C surface. This study results will provide the reference for optimizing the process parameters and researching the material removal mechanism in CMP SiC crystal substrate.

Abstract: A kind of vitrified bond was selected to be sintered with diamond powders to prepare diamond abrasive. The effect of the additive of CeO2 and sintering parameters on the performance of vitrified bond diamond abrasive was investigated. The mechanical properties of diamond abrasives were tested on ZMC-Ⅱ type diamond static strength tester and the interfacial bonding states between diamond powders and vitrified bonds were studied by Scanning Electron Microscopy (SEM). The results indicated that CeO2 improved the performance of diamond abrasive by means of strengthening the bonding between diamond grits and vitrified bond. The admirable diamond abrasive was achieved when the sample was sintered at 800°C holding for 120min.