Structure of a Diamond–Matrix Interface and Durability of a Diamond Tool Fabricated by the Metallization of Diamond with Chromium during Sintering of the WC–Co Briquette with Copper Impregnation

2019 ◽  
Vol 60 (4) ◽  
pp. 441-449 ◽  
Author(s):  
P. P. Sharin ◽  
M. P. Akimova ◽  
S. P. Yakovleva ◽  
V. I. Popov
2020 ◽  
Vol 86 (6) ◽  
pp. 62-71
Author(s):  
P. P. Sharin ◽  
S. P. Yakovleva ◽  
M. P. Akimova ◽  
V. I. Popov

The results of studying fundamental and applied problems regarding the formation of boundary layers between diamond and carbide matrix are presented with the goal to develop a highly resistant diamond tool. The new approaches to the synthesis of diamond-carbide materials combining diamond metallization and sintering in a single-stage technology are presented. The developed technology eliminates the re-heating of a metallized coatings which results in their destruction and enhanced graphitization of diamond (these phenomena restrict using metallization procedure to improve diamond retention and synthesis of high-functional composites for diamond tools). The goal of the study is analysis the structural and phase state of the «diamond – carbide matrix» interface in a diamond tool obtained by the new technology and the main factors determining the level of diamond retention in the presence of a metallized coating. Unique opportunities provided by modern high-resolution methods of research were used in the study. The elemental composition and morphological features of the diamond-matrix interface were studied using the methods of scanning electron microscopy, atomic force microscopy, X-ray microanalysis and Raman spectroscopy. Identification of the reaction products, including non-diamond carbon was performed. It is shown that the introduction of the powder-metallizer significantly modified the contact boundaries and provide conditions for improving the chemical and mechanical adhesion of the diamond-matrix system. The formation of the well-developed nano- and sub-microscale roughness of the diamond surface and dense filling of the existing voids with nanoscale layers of metal-infiltrate was revealed. The multilevel organization of highly structured elements of the transition zone with the minimal graphitization ensured the monolithic character and strength of the diamond-matrix bond. Comparative service tests of preproduction and control samples of diamond dressers proved the efficiency of developed hybrid technology (the specific performance of diamond tools increased by 39 – 45%). New fundamental and applied results have been obtained in the field of studying interface zones in crystalline multiphase systems that can be used to regulate adhesion phenomena at the interphase boundaries and develop highly efficient composite materials.


Author(s):  
P. P. Sharin ◽  
M. P. Akimova ◽  
S. P. Yakovleva ◽  
V. I. Popov

The paper studies the structure, elemental and phase composition of the diamond-matrix interface in a diamond tool for abrasive wheel dressing manufactured using a new hybrid technology that combines thermal diffusion metallization of diamond with chromium and sintering of a matrix based on WC–6%Co carbide powder mixture with copper impregnation in a single cycle of vacuum furnace operation. During matrix sintering, the compact arrangement of chromium powder particles around diamond grains and the shielding effect of copper foil create favorable conditions that ensure the thermal diffusion metallization of diamond. Scanning electron microscopy, X-ray diffraction, and Raman spectroscopy show that temperature-time modes and sintering conditions specified in the experiment provide for a metal coating chemically bonded to diamond that is formed on the diamond surface and consists of chromium carbide phases and cobalt solid solution in chromium providing durable diamond retention in the copper-impregnated carbide matrix. In this case, matrix structure and microhardness except for areas directly adjacent to the diamond-matrix interface remain the same as for the matrix of a powder mixture sintered without chromium. Comparative tests of similar diamond dressing pens were carried out and showed the high effectiveness of the hybrid technology in obtaining diamond-containing composites intended for tool applications. It is shown that the specific productivity of a pen prototype made using the hybrid technology was 51,50 cm3/mg when dressing a grinding wheel of green silicon carbide that is 44,66 % higher than the similar indicator for the sametype check pen made by the traditional method.


2021 ◽  
Vol 1798 (1) ◽  
pp. 012007
Author(s):  
Xia Mingqiang ◽  
SHI Guangfeng ◽  
BI Jiaolong ◽  
GAO Jiyu ◽  
YU Dawei ◽  
...  
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