4381271 Use of fired fibrous graphite in fabricating polycrystalline diamond and/or cubic boron nitride/silicon carbide/silicon composite bodies

Carbon ◽  
1984 ◽  
Vol 22 (1) ◽  
pp. v
Author(s):  
Hayden Stephen C
1989 ◽  
Vol 162 ◽  
Author(s):  
Lawrence C. Snyder ◽  
Arthur H. Edwards ◽  
Peter Deak

ABSTRACTWe have employed a 32 atom cyclic-cluster and the Modified Intermediate Neglect of Differential Overlap (MINDO/3) method to compute the lattice constant, band structure, heat of formation and other properties of cubic boron nitride, diamond and silicon nitride. The computational scheme we have employed will permit studies of defects in these materials.


2014 ◽  
Vol 1017 ◽  
pp. 406-410 ◽  
Author(s):  
Hitoshi Sumiya ◽  
Katsuko Harano

Wear characteristics of binder-less (single-phase) nanopolycrystalline diamond (NPD) and cubic boron nitride (BL-PcBN) were investigated by rubbing them against various ceramics such as SiO2, Si3N4, Al2O3 and SiC. The wear rates of NPD and BL-PcBN against SiO2 and Si3N4 at high speed rubbing (280-360 m/min) at a loading pressure of 55 MPa (starting condition) were considerably high, indicating the main wear process is a chemical reaction. BL-PcBN specimens were found to be worn at much higher (more than ten times) rates than NPD, suggesting that cBN highly reacts with these ceramics in comparison with diamond under the experiment condition.


2017 ◽  
Vol 111 (17) ◽  
pp. 171604 ◽  
Author(s):  
Joseph Shammas ◽  
Yu Yang ◽  
Xingye Wang ◽  
Franz A. M. Koeck ◽  
Martha R. McCartney ◽  
...  

2016 ◽  
Vol 874 ◽  
pp. 543-548 ◽  
Author(s):  
Noritaka Kawasegi ◽  
Kazuma Ozaki ◽  
Noboru Morita ◽  
Kazuhito Nishimura ◽  
Makoto Yamaguchi ◽  
...  

Texturing on the surface of cutting tools is an effective method to improve the friction and resultant machining performances of the tool. In this study, to fabricate nanotextures on various tools used for precision cutting, a patterning method on nanopolycrystalline diamond and cubic boron nitride tools was investigated using focused ion beam (FIB) irradiation and heat treatment. Patterning was possible using this method, and the patterning characteristics were different from those of single-crystal diamond. This method was more suitable for cutting tools compared with direct FIB machining because of its high efficiency and significantly low affected layer.


2020 ◽  
Vol 57 (6) ◽  
pp. 53-64
Author(s):  
N.M. Huliieva ◽  
D.O. Somov ◽  
V.V. Pasternak ◽  
L.M. Samchuk ◽  
T.I. Chetverzhuk

AbstractThe issue of grinding saponite–titanium composites has not been considered in the machine building industry yet. The reason is that the chips are stuck on the working surfaces of abrasive tools made of silicon carbide and electrocorundum. This is due to the high adhesive activity at operating cutting temperatures between the composite and traditional abrasives.The article aims at studying the grinding of saponite–titanium composites using abrasive tools in various cutting modes based on parametric and non-parametric statistical methods.To solve this problem, high porous wheels (HPW) made of cubic boron nitride CBN30 with 100 % concentration on a bond V (K27), a pore-forming KF40, varied grains: B76, B126, B151 (ISO 6106:2013) – and hardness: M and O (ISO 525:2013) were used to grind saponite–titanium composites. Additionally, the Norton wheels from green silicon carbide with a normal porosity 39C (46; 60) K8 VK and with different grain size were tested. Norton wheels provide reduction of roughness height by 1.4–1.5 times in comparison with boron nitride HPW. These are recommended for the finishing grinding stage and HPW CBN30 – the preliminary to reduce the thermal effects on composites. By processing stability, the Norton wheels with grain 46 rank first, and among boron nitride HPW – CBN30 B76 100 OV K27–KF40.


Author(s):  
Balla S Prasad ◽  
Chandra M KarakaVVNR ◽  
Venkata S Annavarapu

The investigation of surface roughness in machined materials/products has proven to be a difficult undertaking. The surface quality is determined not only by the parameters but also by the cutting conditions. Surprisingly, a study indicated that when analysing the quality of machining processes currently being done, surface morphology has a significant impact on tool performance. PCD (Polycrystalline diamond) and PCBN (Poly cubic boron nitride) cutting tools produce a better surface finish, which is explored in the machining of Al-Mg/Zr/TiO2 (15%), nano metal matrix composites (NMMC). The study primarily focuses on determining the best parameters for end milling NMMCs in tests for long-term production sustainability. Using scanning electron microscopy, microstructural study of the machined surface will aid in finding the parameters responsible for the cause of surface integrity. The work focusses on analysing tool performance by monitoring the machining process in real time using signal characteristics, forecasting vibrations (displacement) and machine outputs using surface topography and chip analysis. The tool failure was acquired by establishing a correlation between displacement (vibrations) and post machining outcome of experimental study, as a result, the evolution of displacement in the PCBN tool is 24.7 μm, which is better compared to 34.3 μm in the PCD tool at 3000 r/min. PCBN outperformed PCD with a 1.82 μm surface roughness, resulting in longer tool life. Thus, this economical reliable empirical method the problem of finding difficulty identifying the causing of tool wear and failure by correlating sensor signals features with experimental results.


2013 ◽  
Vol 801 ◽  
pp. 109-116
Author(s):  
Michal Adamik ◽  
Róbert Drlička ◽  
Milan Matúš ◽  
Ján Žitňanský

Hard turning is a turning operation performed on hard materials (hardness more than 45 HRC) in order to reach surface roughness close to that obtained in grinding. The development of this technology was accompanied by the development of new cutting materials such as cutting ceramics, cubic boron nitride and polycrystalline diamond. Especially cubic boron nitride has found its use in hard part turning operations because of its characteristics. However, new cutting materials result in new questions, which researchers are trying to solve. The major consideration for a user of this relatively new technology is the quality of parts produced and how the new cutting material will behave during machining. This paper aims to document and describe the process of wear on the cutting edge of a tool made from cubic boron nitride of a different grade and with a different geometry of the cutting edge, and its influence on surface roughness and quality. Wear was documented by a digital microscope with measurement option. Surface roughness was measured by a roughness meter. A notable observation from this research is that the flank wear of the cutting tool has a large impact on the quality of machined parts (especially surface finish and surface integrity) [1].


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