Correlation of the diamond/matrix interphase zone structure with tool efficiency obtained by technology combining diamonds metallization with matrix sintering

2019 ◽  
pp. 111-123 ◽  
Author(s):  
P. P. Sharin ◽  
M. P. Akimova ◽  
V. I. Popov
Keyword(s):  
Thermal Diffusion ◽  
Shielding Effect ◽  
Specific Productivity ◽  
Grinding Wheel ◽  
Zone Structure ◽  
Chromium Powder ◽  
Carbide Matrix ◽  
Diffusion Metallization ◽  
Effect Of Copper ◽  
Diamond Retention

The paper studies structure and phase characteristics of the interphase zone diamond/matrix in dressers made by thermal diffusion metallization of a diamond combined with matrix sintering based on WC–Co and Cu impregnation. The compact arrangement of chromium powder particles around diamond grains and the shielding effect of copper foil create favorable conditions for thermal diffusion metallization of diamond at matrix sintering. A metallized coating chemically bonded with diamond and consisting of chromium carbide and solid solution of cobalt in chromium phases provides a strong diamond retention in the carbide matrix. It was shown that it is formed on the surface of the diamond under the conditions specified in the experiment and the temperature – time sintering mode. The specific productivity of experimental dresser made by hybrid technology at straightening green silicon carbide grinding wheel equaled 51.50 cm3/mg exceeding that of the control dresser made without metallization of diamonds by sintering with copper impregnation by 44.66%.

Structure of diamond-matrix interface and durability of diamond tool obtained by diamond metallization with chromium during WC–Сo briquette sintering with copper impregnation

2018 ◽  
pp. 64-75 ◽  
Author(s):  
P. P. Sharin ◽  
M. P. Akimova ◽  
S. P. Yakovleva ◽  
V. I. Popov
Keyword(s):  
Thermal Diffusion ◽  
Powder Mixture ◽  
Diamond Tool ◽  
Shielding Effect ◽  
Diamond Surface ◽  
Specific Productivity ◽  
Matrix Interface ◽  
Abrasive Wheel ◽  
Hybrid Technology ◽  
Diffusion Metallization

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.

Structural-Phase State of the Interphase Boundary at Thermal Diffusion Metallization of Diamond Grains by Cr and Ti

2020 ◽  
Vol 992 ◽  
pp. 670-675
Author(s):  
P.P. Sharin ◽  
M.P. Akimova ◽  
S.P. Yakovleva
Keyword(s):  
Thermal Diffusion ◽  
Interphase Boundary ◽  
Phase State ◽  
Structural Phase ◽  
Cemented Carbide ◽  
Carbide Powder ◽  
Structural Phase State ◽  
Metallized Coating ◽  
Diffusion Metallization ◽  
Diamond Retention

Structural-phase state of the diamond-metallized coating interphase boundary after thermal diffusion metallization of diamond grains by transition metals Cr, Ti were studied. Metallization were conducted under temperature-time mode corresponding to the sintering of cemented carbide matrices with Cu impregnation. The structural-phase state of the metallized coating and diamond-coating interphase boundary was studied by scanning electron microscopy, X-ray phase analysis and Raman spectroscopy. It was found that a thin continuous metal carbide coating chemically bonded to the diamond and consisting of the corresponding metal, their carbides and small amount of graphite phases is formed during thermal diffusion metallization of diamond by Cr and Ti under the conditions specified in the experiment. It was shown that graphite is formed not by a continuous layer, but in the form of local inclusions. This ensures a strong adhesion of the metallized coating to the diamond through the carbides of the corresponding metals. The results can be useful in the development of compositions and technological methods that provide an increased level of diamond retention in the matrices of tools based on cemented carbide powder mixtures.

Features of the Formation of an Interface Zone Structure during Thermal Diffusion Metallization of Diamond by Transition Metals

2020 ◽  
Vol 11 (6) ◽  
pp. 1348-1358
Author(s):  
P. P. Sharin ◽  
M. P. Akimova ◽  
S. P. Yakovleva ◽  
L. A. Nikiforov ◽  
V. I. Popov
Keyword(s):  
Transition Metals ◽  
Thermal Diffusion ◽  
Zone Structure ◽  
Interface Zone ◽  
Diffusion Metallization

The use of high-resolution methods of research in the design of the diamond-matrix interface to increase the durability of the diamond tool

2020 ◽  
Vol 86 (6) ◽  
pp. 62-71
Author(s):  
P. P. Sharin ◽  
S. P. Yakovleva ◽  
M. P. Akimova ◽  
V. I. Popov
Keyword(s):  
High Resolution ◽  
Diamond Tool ◽  
Diamond Surface ◽  
Matrix Interface ◽  
Reaction Products ◽  
Diamond Tools ◽  
Functional Composites ◽  
Mechanical Adhesion ◽  
Carbide Matrix ◽  
Diamond Retention

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.

Thermal diffusion chromium plating of structural carbon steel 20 by high frequency currents

2021 ◽  
pp. 137-145
Author(s):  
N. I. Kitaev ◽  
Yu. V. Yakimovich ◽  
M. Yu. Shigaev ◽  
S. Ya. Pichkhidze
Keyword(s):  
High Frequency ◽  
Surface Hardness ◽  
Chromium Powder ◽  
Gear Teeth ◽  
Chromium Plating ◽  
High Shock ◽  
Temperature Diffusion ◽  
Diffusion Metallization ◽  
Steel 20 ◽  
Structural Carbon Steel

To increase the service life of the gear teeth made of steel 20, operating under high shock loads, their main surfaces were subjected to high-temperature diffusion metallization, namely, chromium plating with high-frequency currents. As a result of diffusion metallization, the surface hardness increased 5.1–5.4 times – from 156–159 HV to 800–866 HV, and the strength level 3.3 times – from 250 to 820 mAh. Optimal parameters for the diffusion metallization: current I = 0.25–0.3 kA, power Pe = 8–10 kW, hardening τ = 8–10 min. By the method of scanning electron microscopy, it was found that after diffusion saturation of the surface of the gear teeth with chromium, the steel has a homogeneous structure with clearly pronounced transition layers, the average thickness of the diffusion layer was 0.06 mm. Energy dispersive analysis showed that after diffusion metallization with chromium powder, the basic composition of the steel remained constant, only the qualitative ratio of the components changed. X-ray phase analysis revealed the presence of an αFe-phase with the incorporation of Cr on the surface of the sample.

Features of the Structural-Phase State of the Diamond-Matrix Boundary Zone in Diamond-Containing Composite Materials

2019 ◽  
Vol 945 ◽  
pp. 756-762
Author(s):  
P.P. Sharin ◽  
M.P. Akimova ◽  
S.P. Yakovleva
Keyword(s):  
Phase State ◽  
Structural Phase ◽  
Cemented Carbide ◽  
Specific Productivity ◽  
Matrix Composites ◽  
Structural Phase State ◽  
X Ray ◽  
Hybrid Technology ◽  
Metallized Coating ◽  
Diamond Retention

Preliminary metallization of the diamond component, which promotes the formation of chemical bonds on the diamond-matrix contact during subsequent sintering, is used to increase the strength of diamond retention and the durability of diamond-containing metal matrix composites. There are restrictions on carrying out metallization to create diamond composites with a cemented carbide matrix, since reheating the metallized coating at high sintering temperatures of carbide powders leads to its destruction, diamond graphitization and deterioration of the material properties. The structural-phase state in the diamond-matrix contact zone has been studied and the main factors providing the strength of diamond retention in diamond-cemented carbide composites obtained by hybrid technology that excludes the reheating of the metallized coating have been revealed. It was revealed, that the developed hybrid technology combining the thermal diffusion metallization of diamond and sintering according to the self-dosed impregnation scheme in one cycle ensures the production and preservation of the metallized coating by the methods of scanning electron microscopy, X-ray diffraction and X-ray phase analysis, Raman spectroscopy. Comparative tests have been carried out and it is shown that the specific productivity of experimental samples of a diamond tool (ruling pencils) with a metallized diamond component is on 39% higher than same parameter of pencils without metallization.

Structural-Phase State of the Interphase Boundary at Thermal Diffusion Metallization of Diamond Grains by Fe, Ni and Co

2020 ◽  
Vol 992 ◽  
pp. 676-682
Author(s):  
P.P. Sharin ◽  
M.P. Akimova ◽  
S.P. Yakovleva
Keyword(s):  
Thermal Diffusion ◽  
Interphase Boundary ◽  
Phase State ◽  
Structural Phase ◽  
Adhesive Interaction ◽  
Experimental Conditions ◽  
Structural Phase State ◽  
Metallized Coating ◽  
Diffusion Metallization ◽  
Complex Structural

Structural-phase state of the diamond-metallized coating interphase boundary after thermal diffusion metallization of diamond grains by transition metals Fe, Ni and Co were studied. Metallization were conducted under temperature-time mode corresponding to the sintering of cemented carbide matrices with Cu impregnation. The structural-phase state of the metallized coating and diamond-coating interphase boundary was studied by scanning electron microscopy, X-ray phase analysis and Raman spectroscopy. A metallized coating strongly adhered to the diamond forms during thermal diffusion metallization of diamond by iron. The metallized coating has a complex structural phase composition of iron, a solid solution of carbon in iron and graphite phases. Nickel and cobalt cause intense catalytic graphitization of diamond with the formation of numerous traces of erosion on its surface under the heating conditions specified in the experiment. The observed weak adhesive interaction of these metals with diamond is probably due to the high melting temperatures of the Ni-C and Co-C eutectics, which does not allow the metals to react with diamond under given experimental conditions.

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