Investigation on the Modification Methods to Ceramic Cutting Tools

2007 ◽  
Vol 280-283 ◽  
pp. 1197-1202 ◽  
Author(s):  
He Zhuo Miao ◽  
Zhi Jian Peng ◽  
Wen Jie Si ◽  
Long Hao Qi ◽  
Jiang Hong Gong ◽  
...  
Keyword(s):  
Surface Modification ◽  
Ion Implantation ◽  
Young’S Modulus ◽  
Bending Strength ◽  
Flank Wear ◽  
Young's Modulus ◽  
Cutting Tools ◽  
High Energy ◽  
High Energy Density ◽  
Dispersion Strengthening

There are too many methods to enhance the performance of ceramic cutting tools. All the methods can be sorted into two types: inner modification and surface modification. One of the main method to the inner modification of ceramic cutting tools is dispersion strengthening. Usually, in order to enhance the performance of ceramic cutting tools, some dispersed phases of TiN, TiC or TiCN, Al2O3, and/or ZrO2, and so on, and/or some whiskers, or fibers were added into the ceramic matrixes. And the new types of cutting tools, which possessed much more excellent performance than the original ones, were called composite ceramic cutting tools. For the composite Si3N4-based ceramic, Al2O3-based ceramic, and TiCN-based cermet, the cutting efficiency could be enhanced to 3~10 times, compared with cemented carbide tools. And they can be used for rough and finish machining of various cast iron workpieces and hardened steels, respectively, including milling and planning. Ion implantation is a surface modification for ceramic cutting tools. With certain doses of metals, for example, titanium, zirconium and chromium, and so on, implanted into the ceramics, the hardness, Young’s modulus, fractural toughness, and bending strength, etc., can be enhanced. For Al2O3 and Si3N4 ceramics, the hardness, Young’s modulus, and bending strength increased with a maximum factor of 50%, and the flank wear decreased with a factor of 2~12, compared with the unimplanted ceramic cutting tools. However, the main shortcoming of ion implantation to modify ceramics is the thickness of modified layers. They are, usually, too thin for cutting tools. The so-called PHEDP, pulsed high energy density plasma, is another surface modification method for ceramic cutting tools proposed recently. With such method, much thicker coatings of TiN, TiCN and (Ti,Al)N, etc, were deposited onto Si3N4 and WC ceramic cutting tools.The main merits involved in high hardness and Young’s modulus of the coatings, low residual stresses, and good adhesive strength between the coatings and substrates. And the flank wear of the as-depositedtools decreased with a factor of 5~10.

scholarly journals The Role of Thin-Film Vacuum-Plasma Coatings and Their Influence on the Efficiency of Ceramic Cutting Inserts

Coatings ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 287 ◽  
Author(s):  
Marina Volosova ◽  
Sergey Grigoriev ◽  
Alexander Metel ◽  
Alexander Shein
Keyword(s):  
Bending Strength ◽  
Surface Defects ◽  
Cutting Tools ◽  
High Energy ◽  
Radius Of Curvature ◽  
Sic Ceramic ◽  
Operational Tests ◽  
Mechanical Fastening ◽  
Cutting Inserts ◽  
The Impact

The main problem with ceramics used in cutting tools is related to the unpredictable failures caused by the brittle fracturing of ceramic inserts, which is critical for the intermittent milling of cyclic loading. A 125-mm-diameter eight-toothed end mill, with a mechanical fastening of ceramic inserts, was used as a cutting tool for milling hardened steel (102Cr6). For the experiments, square inserts of the Al2O3 + SiC ceramic were used and compared with the samples made of Al2O3 + TiC to confirm the obtained results. The samples were coated with diamond-like coating (DLC), TiZrN, and TiCrAlN coatings, and their bending strength and adhesion were investigated. Investigations into the friction coefficient of the samples and operational tests were also carried out. The effect of smoothing the microroughness and surface defects in comparison with uncoated inserts, which are characteristic of the abrasive processing of ceramics, was investigated and analyzed. The process developed by the authors of the coating process allows for the cleaning and activation of the surface of ceramic inserts using high-energy gas atoms. The impact of these particles on the cutting edge of the insert ensures its sharpening and reduces the radius of curvature of its cutting edges.

Improvement in self-discharge of Zn anode by applying surface modification for Zn–air batteries with high energy density

2013 ◽  
Vol 227 ◽  
pp. 177-184 ◽  
Author(s):  
Sang-Min Lee ◽  
Yeon-Joo Kim ◽  
Seung-Wook Eom ◽  
Nam-Soon Choi ◽  
Ki-Won Kim ◽  
...  
Keyword(s):  
Surface Modification ◽  
Energy Density ◽  
High Energy ◽  
High Energy Density ◽  
Zn Anode

scholarly journals Selection of technologies for metal film application using physical deposition techniques

2020 ◽  
Vol 20 (3) ◽  
pp. 280-288
Author(s):  
S. P. Glushko
Keyword(s):  
Thin Films ◽  
Ion Implantation ◽  
Ion Beam ◽  
Cutting Tools ◽  
High Energy ◽  
Metal Films ◽  
Ion Beam Sputtering ◽  
Wear Resistant Coatings ◽  
Beam Sputtering ◽  
Physical Deposition

Introduction. Obtaining high-quality thin metal films is important for advances in the technologies of applying antifriction and wear-resistant coatings on cutting tools or parts of friction couples. Various techniques of physical film deposition are applied using technologies of cathode (ion), magnetron and ion beam assisted sputtering. The work objective is to analyze, compare and determine the feasibility of techniques for the physical deposition of thin metal films when applying antifriction and wear-resistant coatings on cutting tools or parts of friction couples. Materials and Methods. Technologies of cathode (ionic), magnetron and ion-beam sputtering are considered. Schematic diagrams, conditions and parameters of the considered processes are presented. Results. An advanced technology for the deposition of thin films, alloying and hardening of the surfaces of metal parts is magnetron sputtering. Continuous wave (cw) magnetrons are used to apply coatings of complex composition or multilayer coatings on flat substrates. Ion beam sputtering is considered a slow sputtering of the target surface by bombardment with a high-energy ion beam and deposition on the substrate surface. Under the ion implantation, the surface of metals is doped with recoil atoms, which receive high energy from accelerated ions and move a few nanometers deeper. This enables to obtain ultra-thin doped layers. Low temperature of ion implantation, the possibility of sufficiently accurate control of the depth and the impurity distribution profile, create the prerequisites for the process automation. Wear tracks are more acidified under the same wear conditions on implanted steel compared to non-implanted steel. The nonequilibrium process under ion implantation causes the formation of such alloys in the surface layers that cannot be obtained under normal conditions due to diffusion of components or limited solubility. Ion implantation makes it possible to obtain alloys of a certain composition in the surface layer. Surface properties can be optimized without reference to the bulk properties of the material. Implantation is possible at low temperatures without a noticeable change in the size of the product.Discussion and Conclusion. Cathode (ion), magnetron and ion-beam sputtering have common advantages: due to the relatively low temperature, the substrate does not overheat; it is possible to obtain uniform coatings; the chemical composition of the deposited coatings is accurately reproduced. The rest of the advantages and disadvantages of the considered methods are individual. The results can be used to create thin films through alternating magnetron and then ionbeam deposition processes, which enables to obtain films uniformly modified in depth. This is important in the production of parts of friction couples and cutting tools to improve their quality.

Evaluation of Decalcification Induced Changes in Bone Strength Using Electrical Conductivity Measurements

2014 ◽  
Author(s):  
Vladislav Sevostianov
Keyword(s):  
Electrical Resistivity ◽  
Electrical Properties ◽  
Cortical Bone ◽  
Young’S Modulus ◽  
Bone Strength ◽  
Acid Treatment ◽  
Bending Strength ◽  
Young's Modulus ◽  
Testing Machine ◽  
Mechanical And Electrical Properties

The paper focuses on the effect of decalcification on microstructure and the mechanical and electrical properties of cortical bone. Decalcification is produced by placing the specimens into 5% vinegar acid for 72 hours. This acid treatment leads to a decrease in mass of the specimens 7.78 % (averaged over ten acid treated specimens). Microstructure of natural bone and acid treated bone is then compared using confocal microscopy. To estimate effect of acid treatment on electrical resistivity of bone, the specimens are rinsed and saturated with 0.9% NaCl solution for ten minutes. Then electrical resistance is measured by the four-point method and electrical resistivity is calculated. Averaging over ten acid treated specimens and ten control specimens show that decalcification lead to increase of electrical resistivity 5.85 times. Comparison of mechanical properties of natural and acid treated bones is done by three point bending using Instron 5882 testing machine. It is observed that 7.78 % mass loss in cortical bone yields reduction of the Young’s modulus about 2.7 times and bending strength of the specimens by 35%. A positive correlation between change in strength and Young’s modulus and electrical resistivity of the individual specimens is observed. The obtained results allows one to estimate changes in mechanical and electrical properties of bone from known losses in bone mass and, thus, non-destructively evaluate the decrease in bone strength through changes in electrical resistivity.

Structure of the Coatings onto Ceramic Cutting Tools Deposited by Pulsed High Energy Density Plasma

2007 ◽  
Vol 280-283 ◽  
pp. 1207-1210
Author(s):  
He Zhuo Miao ◽  
Zhi Jian Peng ◽  
Long Hao Qi ◽  
Feng Shi ◽  
Wen Jie Si
Keyword(s):  
Energy Density ◽  
Cutting Tools ◽  
High Energy ◽  
Grain Structure ◽  
High Energy Density ◽  
Pulsed Plasma ◽  
Solid Solution Strengthening ◽  
Coated Tools ◽  
Columnar Grain ◽  
Density Plasma

With a newly-developed technique, pulsed high energy density plasma (PHEDP), TiN, TiCN, and (Ti,Al)N coatings were deposited onto silicon nitride and cemented carbide cutting tools. The structures of these coatings were systematically investigated in this paper. The average surface roughness (Ra) of the coated tools were ranged in 20~150 nm. The smooth surface of coated tools means that the coatings are promising candidate for cutting tools of high precision and it is in favor of reducing the fiction coefficients and flank wear of tools. The coating thickness varied, in the range of 3~20 µm, with the deposition conditions of the shot number of pulsed plasma, and the voltages between the inner and outer electrodes of the coaxial gun. The coating has a densified structure compared to the substrate structure and almost no pores and cracks exist in the coating surface. The grain sizes of the coating were small (<100nm), much finer than those of the substrate (>2 µm). Except for TiN-Si3N4 system, no apparent columnar grain structure as presented predominantly in typical vapor deposited coatings was observed. In fact, an equiaxed structure was presented, due to the pulsed mode of plasma bombardment and solid solution strengthening of C or Al into TiN lattices, resulting in disruption, through renucleation, of epitaxy on individual columns. A continuous and densified interface was observed. All these characteristics in structures promised an excellent performance of the coated tools.

THE INFLUENCE OF THE MULTILAYER STRUCTURE OF HARD COATINGS ON THEIR RESISTANCE TO MICRO-IMPACT FATIGUE WEAR

Tribologia ◽  
2020 ◽  
Vol 290 (2) ◽  
pp. 37-45
Author(s):  
Jolanta KRUPA ◽  
Grzegorz WIĄZANIA ◽  
Sławomir ZIMOWSKI ◽  
Marcin KOT
Keyword(s):  
Young’S Modulus ◽  
Sliding Friction ◽  
Young's Modulus ◽  
Multilayer Coating ◽  
Cutting Tools ◽  
Fatigue Cracking ◽  
Hard Coatings ◽  
Impact Fatigue ◽  
Fatigue Wear ◽  
Erosion Processes

Fatigue cracking of thin hard anti-wear coatings occurs, among others, in the tribological contact of sliding friction pairs, in the top layers of cutting tools coatings, as well as in the surface of elements subjected to erosion processes. Coating fatigue wear is initiated as a result of cyclic interactions with micro-roughness of counterpart or other elements or particles that repeatedly impact the surface. The selection of appropriate coatings can increase the durability of machine components that are subjected to fatigue impact loads. The paper presents the results of tests on micro-impact fatigue wear of elements covered with single TiN and DLC coatings, as well as multi-layer (Ti/TiN)×8 type. Fatigue tests were carried out using the micro-impact method by cyclic impact of the surface of the coating with a diamond ball. The experiments were performed using a special laboratory stand. The correlation between fatigue life of coatings and their micromechanical properties such as Young's modulus and hardness were also examined. The hardness and Young's modulus were determined by an instrumented indentation method. The test results proved that the (Ti/TiN)×8 multilayer coating demonstrates wear 1.4 times smaller than the sample with the TiN coating and 1.2 than the sample with the DLC coating.

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