Bond Diamond Tools Research Articles

Highly wear resistant metal bond for diamond tool based on two-step reactive sintered Fe3Al

Metal bond diamond tools are regularly used in the machining of various hard and brittle materials. The mechanical properties and wear resistance of the metal bond are very important for the tool's life and machining performance. Herein, a low-cost and highly wear resistant Fe3Al bonded material for diamond tool was proposed. A novel two-step reactive sintering method, integrating short-term high-temperature reactive sintering and long-term low-temperature densification sintering, was proposed to prepare Fe3Al bond diamond tools. The effect of sintering temperature on the microstructure and mechanical properties of the Fe3Al bond was examined during one-step reactive sintering. The mechanical properties and tribological characteristics of the one-step and two-step reactive sintered Fe3Al and commercial Fe alloy bond were compared. The machining performance of the two-step reactive sintered Fe3Al bond diamond tool on sapphire was also examined and compared to that of a commercial Fe alloy bond diamond tool. The results showed that the relative density and mechanical properties of the Fe3Al bonded material were enhanced by increasing the sintering temperature during one-step reactive sintering. Moreover, the sample sintered at 1150-850 °C exhibited better mechanical properties and wear resistance compared to the one-step reactive sintered Fe3Al and commercial bond. The grinding ratio of the two-step reactive sintered Fe3Al bond diamond tool was 157 % higher than that of the commercial Fe alloy bond diamond tool.

Experimental investigation of Aluminum Nitride ceramics based on compliant finishing process

Aluminum Nitride (AlN), as a type of advanced functional ceramic material, has found wide applications in many fields, owing to its advantageous properties such as excellent thermal conductivity, high hardness and strength, etc. Nevertheless, these beneficial features bring great challenges to its machinability using current existing methods that commonly result in unsatisfactory surface qualities. In this paper, we investigated the processing performance of AlN by introducing the compliant bonnet finishing approach based on different tool bonding materials and abrasive sizes. The distinctive finishing qualities, material removal rates, tool wear behavior, etc., were studied and compared under various process conditions. Unlike other ceramics, resin bonded diamond tools with a 3 μm abrasive size exhibit significant wear when used on AlN ceramics. The curves for tool wear amount and wear rate are investigated. Meanwhile, compliant tool with the smaller abrasive can obtain the sub-50 nm surface roughness. The comparison with traditional rigid pellet finishing further demonstrates the advantageous finishing performances by using compliant tools on the AlN ceramics.

Fabrication and evaluation of high-entropy alloy reinforced Fe bond diamond tool

Metal-bond diamond tools find extensive use in the grinding of hard and brittle materials. The mechanical properties and wear resistance of the metal bond are crucial for the grinding performance and life of diamond tools. However, Fe bonds exhibit insufficient hardness, strength, and wear resistance, and existing reinforcement methods are difficult to simultaneously improve the self-sharpness and wear resistance of diamond tools, leading to a trade-off between grinding performance and life. In this paper, a novel AlCoCrFeNi HEA particles reinforced Fe (HEA/Fe) alloy was proposed as the bond for diamond tool to address the aforementioned issue. The work considers materials science fundamentals related to the element diffusion mechanism and particle reinforcement mechanism in the design of the HEA/Fe bond. Through the mutual element diffusion between the HEA and Fe matrix, expanded HEA regions are formed, which not only enhance the strength and overall wear resistance of the HEA/Fe bond but also generate a composite structure with varying hardness. The distinct mechanical properties of composite structure form wear-resistant and non-wear-resistant areas within the diamond tool, effectively balancing the challenging trade-off between wear resistance and self-sharpness. This allows HEA/Fe bond diamond tools to achieve both prolonged service life and high grinding performance. The results reveal that the HEA/Fe bond diamond tool exhibits a lower grinding force, a superior surface finish, and a nearly equivalent grinding ratio compared to the commercial Fe-based alloy bond diamond tool in grinding of sapphire.

Wear evolution of metal bond diamond tool in grinding of sapphire

The wear characteristics of the metal bond diamond tools changes with the grinding process, resulting in affecting the grinding efficiency, tool's life, and surface integrity of the workpiece. In this study, the wear evolution of a metal bond diamond tool, for the case of grinding of sapphire, is investigated by using a novel design of the grinding setup. The wear characteristics of the diamond grits and the metal bond at a fixed zone of the grinding tool were examined. In addition, the evolution of the grinding process, the grinding force, the grinding ratio, and the surface integrity of the sapphire were also evaluated. As the material removal volume increases, the number of participating diamond grits, the proportion of micro-fractured diamond grits, and the average diamond grit protrusion height increase during the grinding process. And the proportion of newly exposed diamond grits decreases and the distribution of protrusion height of diamond grits becomes narrower during the grinding process. Consequently, a higher grinding ratio, stable grinding force, and excellent ground surface integrity are achieved positively when the wear of the metal bond diamond tool transforms from the initial stage to the stable stage with the material removal volume of up to 3600 mm3.

A comparative study on FeAl and NiAl bonded diamond tools for dry grinding based on wear characteristics at elevated temperature

Dry grinding is considered an environmental-friendly machining process to reduce the utilization of coolant consisting of a complex mixture of chemical components and water. Thus, high mechanical properties at elevated temperatures are necessary for the metal bond diamond tools in dry grinding hard and brittle material, such as ceramics and stones. In the present study, the preparation of FeAl and NiAl by reactive sintering is proposed as the bond of diamond tools for dry grinding. The compressive properties and wear characteristics of FeAl and NiAl are compared at elevated temperatures. Furthermore, the diamond tools based on FeAl and NiAl are prepared, and their dry grinding performance on Si3N4 ceramic is examined. The results reveal that FeAl is characterized by higher compressive yield strength than NiAl at temperatures between 400 °C and 800 °C. Compared to NiAl, FeAl exhibits a higher friction coefficient, wear resistance, and a higher tendency to react with Si3N4 to increase adhesion. Hence, in dry grinding of Si3N4 ceramic, the FeAl-bonded diamond tool produces a higher grinding ratio, higher grinding force and temperature, and slightly lower surface roughness than NiAl.

An environment-friendly metal bond diamond tool based on reactive sintered Fe3Al and grinding performance on ceramics

Metal bond diamond tools have been extensively employed to grind a wide variety of hard and brittle materials. However, numerous heavy metal elements (e.g., Co, Cu, Ni, Cr, Sn and Zn) have been introduced into the metal bond to enhance the hardness and strength, so as to enhance the grinding performance of diamond tool. Some of the heavy metal elements pose a hazard to the environments and operators in the manufacturing and machining process of diamond tools. Herein, an environment-friendly metal bond was proposed for diamond tool based on the reactive sintered Fe3Al, which contained only the strengthening elements of Si, C, and Ti. The effect of sintering temperature on microstructure and mechanical properties of Fe3Al and the effect of adding C (graphite), Si, and Ti (TiH2) on the properties of the metal bond were investigated. A diamond tool was prepared based on the optimized composition and sintering parameter, and its grinding performance on Al2O3 and Si3N4 ceramics was compared with a commercial diamond tool. The results indicated that the hardness and flexural strength of bonded material increased with the sintering temperature and the content of the additives. The highest hardness and flexural strength were obtained for the bond containing 0.5% of graphite, 1% of Si, and 3% of TiH2 at the sintering temperature of 1250 °C. Compared with commercial diamond tool, the prepared diamond tool exhibited significantly lower grinding forces, similar grinding ratio for Al2O3 ceramic, and a slightly lower grinding ratio for Si3N4 ceramic.

Numerical modeling of thermal behavior of melt pool in laser additive manufacturing of Ni-based diamond tools

In this paper the heat absorption, heat transfer and solidification evolution of melt pool in the laser additive manufacturing of Ni–Cr metal bonded diamond tools were studied. Based on the ray tracing theory, the influence of diamond and Ni–Cr alloy powder parameters on laser energy absorptivity was analyzed and the temperature model of mixed powder bed was constructed. Combined with the model and experiment, the impact of the diamond itself and its arrangement on the temperature distribution and shape of melt pool was explored and compared. The change rule of melt pool and microstructure in laser multi-track scanning was investigated. The evolution of melt pool solidification and microstructure with the influence of diamond was revealed. The results show that the powder thickness has a great influence on laser energy absorptivity. The diamond has obvious influence on the temperature distribution and geometry of melt pool, and the influence degree and variation rule are related to the diamond arrangement and position. In the process of laser multi-track scanning, the temperature increases and the geometry of melt pool enlarges gradually. Near the diamond, the diamond changes the direction of temperature gradient of metal melt, accelerates crystals solidification, makes the growth direction of crystals approximately perpendicular to diamond, and increases the endogenetic nucleation phenomenon of crystals near the diamond interface.

Modeling of thermal processes in the contact zones of fuel elements

In this work, using two specific examples, a general approach to the mathematical modeling of thermal processes in the contact zones of fuel elements in the development and optimization of 
 various technological processes, systems and devices is considered. In the first example, a mathematical model of heat transfer in the contact zone (metal-hybrid thermal interface) between the heat-generating element and the heat-dissipating radiator is considered. In the second case, the thermal process in the processing of materials with a bonded diamond tool in the contact zone "diamond grain – binder – processed material" is considered and analyzed. The general approach to modeling thermal processes in the contact zones of various fuel elements makes it possible to optimize the parameters of technological processing modes and the correct operating conditions for products and systems

Experimental research on the biological in-process dressing (BID) of Cu–Co matrix diamond tools

Biomachining, a recently developed non-traditional machining method, uses extreme microorganisms for the controlled material removal from material surfaces. The present paper proposed a new dressing method—biological in-process dressing (BID)—for metal-bonded abrasive tools. The cell-free culture supernatant filtered from cultured microorganisms was continuously sprayed on the surface of a Cu–Co bonded diamond tool to conduct the dressing process. BID experiments were conducted on a series of fixed diamond pads for the lapping of silica glass and sapphire. The material removal rate (MRR), machined surface roughness (Sa), tool surface topography, and thickness loss of the diamond tool were measured during lapping experiments. It was found that BID effectively exposed all diamond grains and improved the machining quality and efficiency. The dressing mechanism of BID was schematically illustrated.

Fabrication and performance evaluation of metal bond diamond tools based on aluminothermic reaction

Herein, the fabrication of metal bond diamond tools is proposed by using the Fe2O3-Al aluminothermic reaction. Moreover, the influence of sintering temperature and TiH2- and Si-doping on phase composition and mechanical properties of the reactive sintered bond is investigated. Furthermore, the grinding performance of metal bond diamond tool on ceramic tile is also examined. At 930 °C, the sintered bond is composed of Fe, Al2O3, Fe3O4 and FeO phases. However, the aluminothermic reaction initiated at 1028.8 °C and resulted in the formation of FeAl2O4 and Fe3Al phases. Moreover, the content of Al2O3, Fe3Al, α-Fe and FeAl2O4 phases increased with the increase of sintering temperature. The maximum flexural strength, hardness and relative density are achieved when sintering at 1230 °C. In addition, the dehydrogenation of TiH2 can impede the formation of FeAl2O4 phases and improve the flexural strength, hardness and relative density of the bond. Also, the Si-doping into Fe2O3-Al aluminothermic reaction system resulted in Fe2Al3Si3 phase and reduced the content of Al2O3 and Fe3Al phases, leading to higher flexural strength, lower hardness and inferior relative density. In wet grinding, the as-prepared metal bond diamond tool can be used to grind ceramic tiles with lower grinding force and better surface quality than the dry grinding. However, the as-prepared metal bond diamond tool rendered low wear resistance due to the brittle nature of the metal bond.

Effects of nano aluminum nitride on the microstructure and mechanical properties of vitrified bond diamond tools

Effects of nano aluminum nitride on the microstructure and mechanical properties of vitrified bond diamond tools

Effect of fly ash cenosphere@SiO2 core-shell microspheres on physical properties and microstructures of vitrified bond diamond tools

Core-shell structure (FA@SiO2) pore former is employed to fabricate high porosity and low mechanical behavior loss vitrified bond diamond abrasive tools. Four different pore former contents i.e. 2, 4, 6, and 8 wt% are used to fabricate the composites. The effects of content of the FA/FA@SiO2 on the phase, morphology structure, open porosity, fracture strength, as well as Rockwell hardness of the FA/FA@SiO2 pore former in the composite are investigated. With increasing FA/FA@SiO2 content from 0 to 8 wt%, open porosity of the composites increases significantly and fracture strength drops ~15%. As compared with FA composite, FA@SiO2 composite exhibits improved pore structures, thus suppressing dramatically bending strength loss and grade loss while remains high porosity. Moreover, the FA@SiO2 in the matrix facilitates the enhancement of interfacial debonding owing to the high contact area, supported SiO2 interlayer and processes of early crack capture at FA@SiO2/glass matrix interface. Therefore, the 4 wt% FA@SiO2 composite shows superior bending strength and hardness (65.08 MPa; 46.25 HRB), which are 15% and 37% higher than those of 4 wt% FA composites (56.33 MPa; 33.67 HRB).

Simulation, forming process and mechanical property of Cu-Sn-Ti/diamond composites fabricated by selective laser melting

Metal bond diamond abrasive tools with complex structure and high wear efficiency will be widely used in the geological drilling and mechanical processing industries, but are difficult to manufacture by traditional technology. In this paper, selective laser melting (SLM), as one of the additive manufacturing technologies, was used to fabricate Cu-Sn-Ti bonded diamond abrasive composites. Simulations, experiments and characterization were carried out to obtain the appropriate SLM process parameters. Results indicated that the optimal SLM parameters were laser power of 260 W, scanning speed of 300 mm/s and layer thickness of 0.09 mm. Furthermore, the wear resistant performance of SLM sample was compared with hot-pressed sintered sample in terms of mass loss rate, wear morphology and bonding condition. Results showed that diamond particles were seriously pulled-out from hot-pressed sintered sample while this hardly occurred from the wear surface of SLM sample, which was benefited from higher amounts of TiC around the diamond. Consequently, the bonding force to diamond was effectively improved for SLM sample. Therefore, SLM method cannot only fabricated sample with complex structures, but also with better performance. This study provides a novel approach for forming metal bonded diamond tools by SLM in the future.

Preparation a nickel-aluminide bonded diamond tool by self-propagating high-temperature synthesis and strengthening by nickel-chromium-phosphorus alloy and copper

Metal bonded diamond tools are normally manufactured by hot-press sintering, which is a high energy consuming process and using a large number of graphite moulds as well. Graphite dust is hazardous to operator's health and environment in machining of graphite mould. In present study, a metal bonded diamond tool is manufactured by self-propagating high-temperature synthesis (SHS) without hot press sintering and consuming of graphite moulds. In order to improve bonding of diamond grit and flexural strength of the tool for this method, nickel‑chromium‑phosphorus alloy and copper are introduced into nickel‑aluminum SHS in present study. The influence of nickel‑chromium‑phosphorus alloy and copper content on the combustion processes, the thermal behaviors, and the microstructures of the synthesized composite bonds are examined in detail. A diamond tool based on the optimized composite is prepared, and the grinding performance is examined. The results reveal that the addition of nickel‑chromium‑phosphorus alloy and copper inhibited the SHS reaction of nickel‑aluminum and reduced the combustion velocity, combustion temperature and reaction exothermic enthalpy. Copper can significantly improve flexural strength of the nickel aluminide bond. However, the maximum of nickel‑chromium‑phosphorus alloy or copper is about 60 wt% to sustain the SHS. A homogeneously dispersed and interconnected nickel-chromium-phosphorus phase in the matrix of nickel aluminides can be obtained with addition of over 40 wt% nickel‑chromium‑phosphorus alloy. A continuous chromium rich layer, composed of chromium carbide, has been formed at the interface between diamond grit and matrix, which renders a chemical bond of diamond grit. On the basis of the addition of 40 wt% nickel‑chromium‑phosphorus alloy and 10 wt% copper, an interconnected nickel‑chromium‑phosphorus phase for strong bonding of diamond grit and a flexural strength up to 700 MPa are achieved, which is considered as an excellent candidate material for diamond tools. The grinding test shows that the diamond tool owns a sound machining ability on the granite, and the diamond grit can be well retained and protruded.

Calculation of Thermal Processes in a Bonded Diamond Tool During Grinding of Glass and Other Materials

The results of calculations of thermal processes occurring in a bonded diamond tool during grinding of different materials on the surface in the contact zone with the machined material and in the interior of the diamond tool are presented. Amathematical model of the heating of the binder of the diamond tool as a result of friction in the grinding zone and cooling by a cutting liquid (CL) is described.

Preparation of Ni3Al bonded diamond core drill with Ni–Cr alloy and its performance on glass–ceramic

In this study, Ni3Al was investigated as bonding material for diamond tools due to its excellent oxidation resistance and high temperature mechanical properties. Ni3Al powder was firstly prepared by self-propagating high temperature synthesis (SHS). The effect of Ni-Cr alloy content in bonding material on microstructure and mechanical properties of Ni3Al bonded diamond tools was investigated. Diamond core drills bonded by Ni3Al and Ni-Cr were prepared, and drilling performance on glass-ceramic was also examined. Results show that relative density, hardness and bending strength of diamond tool increase with the increase in Ni-Cr content. Diamond core drill bonded with Ni3Al-30 vol% Ni-Cr shows lower drilling force than that of the drill bonded with Ni3Al.

High-Efficiency Materials-Processing Technology Based on New Types of Diamond Tools

Examples are presented of the successful application of new types of diamond tools for high-efficiency processing of a wide class of materials such as glass, ceramic, sapphire, semiconductor materials, and different metals. The advantages of a bonded diamond tool based on heat-conducting polymer composite are shown.

Effects of added nano titanium on the microstructure and mechanical properties of vitrified bond diamond tools

• A large number of rutile TiO 2 phases were detected in the specimen added with 50 vol% nano Ti.

Properties of nano-SiC/Ni composite coating on diamond surfaces

ABSTRACTA Ni coating and nano-SiC/Ni composite coating were prepared on diamond surfaces by an electro-co-deposition method. The surface morphology of plated diamond grit and the bonding state between diamond and Fe-matrix bond were characterised by the scanning electron microscopy and energy-dispersive spectroscopy (EDS). The flexural strength and wear resistance performance of the Fe-matrix bonded diamond tool bits were tested. The results showed that the nano-SiC/Ni composite coating possesses a smoother, finer, and denser microstructure when compared with a pure Ni coating. Furthermore, the nano-SiC/Ni composite coating on diamond surfaces improved the flexural strength and wear resistance of Fe-matrix bonded diamond tool bits. The EDS analysis indicated that the chemical combination between diamond grits and Fe-matrix bonding was formed, thereby the mechanical properties of Fe-matrix bonded diamond tool bits were enhanced.

Effect of fly ash cenosphere pore formers on the microstructure and mechanical properties of vitrified diamond grinding wheels

This paper focuses on the influence of fly ash cenosphere (as a pore former) content and particle size on the porosity, microstructure and mechanical properties of vitrified bond diamond tools. The sintered specimens were examined using comprehensive thermal analysis, X-ray diffraction, Raman spectroscopy, scanning electron microscopy, three point bending tests and porosity measurements. The porous morphological parameters (volume, size and distribution of pores) of the sample correlated with the content and size of the fly ash cenosphere, and diffusion layers were formed between the pore former and the vitrified matrix. The bending strength of the porous vitrified matrix varied between 27.28 and 35.92MPa as the porosity changed from 40.66–43.97%. Based on response surface methodology (RSM) studies, two second-order response models for the open porosity and bending strength were established, and the utilization of the response surface model was evaluated with regards to the content and size of fly ash cenosphere present.