Efficiency of Hybrid Sintering Technology for Cemented Carbide Diamond-Containing Composites with Impregnation, Including Thermal Diffusion Metallization of Diamonds

2019 ◽  
Vol 945 ◽  
pp. 749-755
Author(s):  
P.P. Sharin ◽  
M.P. Akimova ◽  
S.P. Yakovleva
Keyword(s):  
Hard Alloy ◽  
Thermal Diffusion ◽  
Technological Process ◽  
Alloy Matrix ◽  
X Ray ◽  
Hybrid Technology ◽  
Diamond Tools ◽  
Diamond Particles ◽  
Metallized Coating ◽  
Diffusion Metallization

For the enhancement of chemical and mechanical adhesion of natural diamond particles with a hard-alloy matrix during the synthesis of diamond-abrasive composites the hybrid technology which combined in one technological process the thermal diffusion metallization of diamond particles and sintering by the developed scheme of the self-dosed impregnation is proposed. This technology does not include a reheating of the metallized coating that causes its destruction and enhances graphitization of diamond thus limiting the application of metallization method for improvement of diamond retention and creation of high-functional composites for diamond tools. Formation and preservation of adhesion-durable metallized coating is confirmed by experiments simulating the conditions of high temperature interaction of diamond with a carbide-forming metal and a hard-alloy matrix during the sintering of special samples using the regimes of developed technological process. The structural and phase state of the transition zone is studied by scanning electron microscopy, X-ray structure analysis and X-ray phase analysis of the partition surfaces of the contact zone between the diamond and the matrix obtained by tensile testing of special samples. Comparative service properties tests of prototype and control samples of diamond dressers confirmed efficiency of the developed hybrid technology for the creation of diamond tools.

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 Diamond-Matrix Transition Zone in Hard-Alloy Diamond-Containing Composites with Diffusion Metallization of Diamonds during Sintering with Impregnation

2019 ◽  
Vol 945 ◽  
pp. 763-770 ◽  
Author(s):  
P.P. Sharin ◽  
M.P. Akimova ◽  
S.P. Yakovleva
Keyword(s):  
Hard Alloy ◽  
Structural Phase ◽  
Diamond Surface ◽  
Reaction Products ◽  
Alloy Matrix ◽  
Interphase Interaction ◽  
Interfacial Layers ◽  
The Matrix ◽  
Diffusion Metallization ◽  
Physical And Chemical

The conducted study belongs to a field of fundamental and application-oriented issues of interphase interaction and formation of interfacial layers between a filler and matrix during the synthesis of composite systems. The factors determining the strength of the diamonds retention in a hard-alloy matrix of abrasive composites obtained by the hybrid synthesis technology with thermal diffusion metallization of diamond particles and sintering by a scheme of the self-metering impregnation were studied. Chemical composition, morphology and distribution of the reaction products, the nature of the resulting carbon phases in the contact zone between the diamond and matrix were investigated using scanning electron microscopy, X-ray phase analysis, Raman spectroscopy and atomic force microscopy. It was found that the increase of physical and chemical adhesion of diamond with the matrix during the synthesis of composites by the developed technology occurs due to the formation of high nano- and submicronic roughness of the diamond surface, formation of island-type metallized coating, dense filling of gaps by nanoscale layers of metal-infiltrate. Free carbon (graphite) was found in small quantities in the form of micron dimension separate inclusions. The revealed multilevel hierarchy of the high-structured morphological forms of the elements of the transitional layers has provided the solidity and strength of the joint between diamond and matrix.

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.

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.

Structure and microhardness of binding for diamond tools based on tungsten carbide obtained by impregnation of iron-carbon melt

2021 ◽  
pp. 95-108
Author(s):  
P. P. Sharin ◽  
M. P. Akimova ◽  
S. P. Yakovleva ◽  
V. I. Popov
Keyword(s):  
Tungsten Carbide ◽  
Iron Carbide ◽  
Alloy Matrix ◽  
Metal Base ◽  
X Ray ◽  
Diamond Tools ◽  
Carbide Phases ◽  
High Level ◽  
Graphite Inclusions ◽  
Eutectic Melt

In this work, an experimental modeling of the technology for producing a matrix by sintering a diamond-containing briquette with a filler of tungsten monocarbide powder impregnated with a Fe-C eutectic melt in a vacuum is carried out. The microstructure, elemental and phase compositions of the products formed in the process of sintering a diamond-containing matrix with impregnation with a Fe-C eutectic melt in vacuum have been studied by scanning electron microscopy, X-ray spectral and X-ray phase analyzes, and Raman spectroscopy. It was found that the matrix consists of 61.0% tungsten carbide phases, 17.0% of iron carbide, 16.5% of α-Fe, and 5.5% of graphite. The eutectic Fe-C alloy, which serves as a matrix binder, consists of a ferrite-pearlite metal base with graphite inclusions. It is shown that at the diamond - matrix interface, graphite inclusions are formed not as a continuous layer, but as discontinuous areas along the perimeter of diamond grains. The microhardness of the WC-based matrix impregnated with the Fe-C melt is ~ 11 GPa, which is more than 3 times higher than the microhardness of the WC-Co-Cu hard alloy matrix obtained by sintering with copper impregnation.The research results can be used in the development of technology for the manufacture of wear-resistant matrices of diamond tools of a wide class used in the processing of materials with a high level of hardness.

Chemical partitioning of elements in Ni-base MC-carbide reinforced eutetic superalloys

1983 ◽  
Vol 41 ◽  
pp. 250-251
Author(s):  
E. F. Koch ◽  
E. L. Hall ◽  
S. W. Yang
Keyword(s):  
Alloy Composition ◽  
Volume Fraction ◽  
Lattice Mismatch ◽  
Turbine Blades ◽  
Eutectic Alloys ◽  
Alloy Matrix ◽  
X Ray ◽  
Gas Turbine Blades ◽  
Analytical Electron ◽  
Analytical Electron Microscope

The plane-front solidified eutectic alloys consisting of aligned tantalum monocarbide fibers in a nickel alloy matrix are currently under consideration for future aircraft and gas turbine blades. The MC fibers provide exceptional strength at high temperatures. In these alloys, the Ni matrix is strengthened by the precipitation of the coherent γ' phase (ordered L12 structure, nominally Ni3Al). The mechanical strength of these materials can be sensitively affected by overall alloy composition, and these strength variations can be due to several factors, including changes in solid solution strength of the γ matrix, changes in they γ' size or morphology, changes in the γ-γ' lattice mismatch or interfacial energy, or changes in the MC morphology, volume fraction, thermal stability, and stoichiometry. In order to differentiate between these various mechanisms, it is necessary to determine the partitioning of elemental additions between the γ,γ', and MC phases. This paper describes the results of such a study using energy dispersive X-ray spectroscopy in the analytical electron microscope.

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%.

X-ray radiography applied to an investigation of thermal diffusion

2005 ◽  
Vol 16 (5) ◽  
pp. 1138-1144 ◽  
Author(s):  
S Rondot ◽  
D Erre ◽  
O Jbara ◽  
D Mouze
Keyword(s):  
Thermal Diffusion ◽  
X Ray
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