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

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.

scholarly journals Influencing Factors on the Interface Microhardness of Lightweight Aggregate Concrete Consisting of Glazed Hollow Bead

2015 ◽  
Vol 2015 ◽  
pp. 1-15 ◽  
Author(s):  
Gang Ma ◽  
Yu Zhang ◽  
Zhu Li
Keyword(s):  
Cement Paste ◽  
Lightweight Aggregate ◽  
Interface Structure ◽  
Interfacial Transition Zone ◽  
Lightweight Aggregate Concrete ◽  
Hydration Degree ◽  
Zone Structure ◽  
Interface Zone ◽  
Aggregate Concrete ◽  
Rational Control

Lightweight aggregate concrete consisting of glazed hollow bead (GHB) as lightweight aggregate is studied for the influence of nanosilica (NS) content, prewetting time for GHB, water-cement ratio, and curing humidity, on the interface structure between GHB and cement paste. This research analyzed the influences of various factors on the interface zone structure by measuring microhardness (HV) and hydration degree of cement paste (HD) nearby the interface zone (1 mm) between GHB and cement paste at different periods of aging. Due to the sampling limitation, the interface zone in this test is within 1 mm away from the surface of lightweight aggregate. The HD of cement paste was determined through chemically combined water (CCW) test. The results were expected to reflect the influence of various factors on the interface zone structure. Results showed that the rational control of the four factors studied could fully mobilize the water absorption and desorption properties of GHB to improve the characteristics of the interfacial transition zone.

Study on Action Mechanism of Polyvinyl Alcohol Polymers in High Performance Cement-Based Composites

2011 ◽  
Vol 99-100 ◽  
pp. 1137-1140
Author(s):  
Dong Lin ◽  
Zi Yun Wen
Keyword(s):  
Polyvinyl Alcohol ◽  
High Performance ◽  
Cement Hydration ◽  
X Ray Diffraction ◽  
Action Mechanism ◽  
Zone Structure ◽  
Chemical Action ◽  
Interface Zone ◽  
X Ray ◽  
Binding Material

In order to discuss the action mechanism of polyvinyl alcohol (PVA) polymers in high performance cement-based composites(HPCBC), the effect of PVA on the strength of HPCBC with different ratio of polymer to binding material (P/B) was studied,and action mechanism of PVA polymers in HPCBC were also studied by SEM and X ray diffraction(XRD). Results show that the strength of HPCBC with addition of PVA polymers can be improved greatly,and there exists an optimal P/B with which the strength were upmost; In this experiment, the optimal P/B is 2.5%,and at this point the strength attain extremity with compressive strength and flexural strength of 113.6MPa, 23.0MPa respectively.By using SEM and XRD, it is found that the interface zone structure is improved and so it was of high-density, low-porosity and high adhere-strength, and PVA polymers chemical action works in the course of cement hydration and hardening.

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.

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.

Precipitation in silicon: Microanalysis

1988 ◽  
Vol 46 ◽  
pp. 474-475
Author(s):  
R.W. Carpenter
Keyword(s):  
Transition Metals ◽  
Spatial Resolution ◽  
Thin Foil ◽  
Precipitation Reaction ◽  
High Current ◽  
Reaction Products ◽  
Carbon And Nitrogen ◽  
Dielectric Layers ◽  
Precipitation Processes ◽  
Areas Of Interest

Interest in precipitation processes in silicon appears to be centered on transition metals (for intrinsic and extrinsic gettering), and oxygen and carbon in thermally aged materials, and on oxygen, carbon, and nitrogen in ion implanted materials to form buried dielectric layers. A steadily increasing number of applications of microanalysis to these problems are appearing. but still far less than the number of imaging/diffraction investigations. Microanalysis applications appear to be paced by instrumentation development. The precipitation reaction products are small and the presence of carbon is often an important consideration. Small high current probes are important and cryogenic specimen holders are required for consistent suppression of contamination buildup on specimen areas of interest. Focussed probes useful for microanalysis should be in the range of 0.1 to 1nA, and estimates of spatial resolution to be expected for thin foil specimens can be made from the curves shown in Fig. 1.

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