ON THE USE OF Mo/Mo2C GRADIENT INTERLAYERS IN DIAMOND DEPOSITION ONTO CEMENTED CARBIDE SUBSTRATES

2016 ◽  
Vol 23 (02) ◽  
pp. 1550109 ◽  
Author(s):  
JIE GAO ◽  
HONGJUN HEI ◽  
KE ZHENG ◽  
XUEYAN GAO ◽  
XIAOPING LIU ◽  
...  
Keyword(s):  
Diffusion Layer ◽  
Cemented Carbide ◽  
Binder Phase ◽  
Diamond Coatings ◽  
Diamond Deposition ◽  
Depth Direction ◽  
Gradient Diffusion ◽  
Glow Plasma ◽  
Excellent Adhesion ◽  
Plasma Surface Alloying

Molybdenum/molybdenum carbide (Mo/Mo2C) gradient interlayers were prepared via double glow plasma surface alloying (DGPSA) technique onto cemented carbide (WC–Co) substrates for diamond deposition. The morphologies, phase composition and adhesion of the interlayers were investigated, as well as their effect on the subsequent diamond deposition. The results indicated that the Mo/Mo2C gradient interlayer deposited on WC–Co substrate was composed of 4.0-[Formula: see text]m-thick diffusion layer and 2.7-[Formula: see text]m-thick deposition layer. The Mo concentration decreased gradually with the depth direction whereas the Co and W concentrations increased. As a result, the Co binder phase was completely restricted within the substrate by the diffusion layer. The presence of gradient diffusion layer ensured excellent adhesion of the interlayer. Subsequently, nanocrystalline diamond coatings with excellent adhesion were deposited on the interlayered substrates. Thus, the Mo/Mo2C gradient interlayers deposited via DGPSA technique were demonstrated as a novel option for depositing adherent diamond coatings on WC–Co substrates.

EFFECT OF SUBSTRATE TEMPERATURE ON TANTALUM CARBIDES INTERLAYERS SYNTHESIZED ONTO WC-Co SUBSTRATES FOR ADHERENT DIAMOND DEPOSITION

2019 ◽  
Vol 26 (02) ◽  
pp. 1850138
Author(s):  
SHENGWANG YU ◽  
JIE GAO ◽  
XIAOJING LI ◽  
DANDAN MA ◽  
HONGJUN HEI ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Substrate Temperature ◽  
Surface Alloying ◽  
Diamond Coatings ◽  
Wear Performance ◽  
Smooth Structures ◽  
Tantalum Carbides ◽  
High Roughness ◽  
Glow Plasma ◽  
Plasma Surface Alloying

Tantalum carbides (TaXC) interlayers have been synthesized by double glow plasma surface alloying (DG-PSA) method at different temperature for subsequent deposition of diamond coatings. The evolution of the microstructures, phase composition and adhesion of the interlayers dependent on substrate temperature has been discussed. The results show that the layers are composed of TaXC (i.e. Ta2C, TaC) with nanocrystalline microstructure and small amounts of CoTa2. The layer produced at 700∘C is formed of specific flower-shaped rings embedded in smooth structures. As the temperature increases to 800∘C, interacted rings are covered the full surface, and the surface roughness is increased. As the temperature increases further, the rings are replaced by irregular-shaped pits, caused a decreasing surface roughness. Besides the special microstructure with interactional rings and relatively high roughness, the layer prepared at 800∘C possesses higher adhesion, better wear performance and higher hardness than those of other layers. The coating obtained on the interlayer pretreated at 800∘C exhibits the best adhesion. Thus, the TaXC interlayers synthesized at 800∘C are demonstrated as a suitable option for adherent diamond coatings deposited onto WC-Co substrates.

Plasma Surface Alloying Process of a Fe-W-Mo-Co Surface Age Hardening High Speed Steel

2007 ◽  
Vol 353-358 ◽  
pp. 1741-1744 ◽  
Author(s):  
Zhong Hou Li ◽  
Nai Juan Ren ◽  
Yan Mei Zhang
Keyword(s):  
Diffusion Layer ◽  
High Speed ◽  
High Speed Steel ◽  
Processing Parameters ◽  
Age Hardening ◽  
Surface Alloying ◽  
Plasma Surface ◽  
The Matrix ◽  
Glow Plasma ◽  
Plasma Surface Alloying

The surface age alloy of Fe-Co-W-Mo was formed on 25Cr2Mo2V steel by double glow plasma surface alloying technique. The effects of processing parameters on the depth, composition and constituent phases of surface alloying layer were investigated. Results indicate that the plasma processing parameters influenced significantly the surface alloying process. The composition of the surface layer nears W11Mo7Co23Fe59wt%, the depth of the surface alloying layer is 150μm after processing at 1100°C for 6hr. The microstructure of the cross section was composed of three sub-layers, that is, the deposition layer, the diffusion layer and the matrix. The constituent phases of the deposition layer were Fe7W6 type μ phase Fe2W type laves phase, Fe3Mo and a little amount of M2C type carbide, that of the diffusion layer were α-Fe and some intermetallics.

scholarly journals Multilayer Diamond Coatings Applied to Micro-End-Milling of Cemented Carbide

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3333
Author(s):  
Eduardo L. Silva ◽  
Sérgio Pratas ◽  
Miguel A. Neto ◽  
Cristina M. Fernandes ◽  
Daniel Figueiredo ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
End Milling ◽  
Interfacial Stress ◽  
Cemented Carbide ◽  
Air Cooling ◽  
Micro Machining ◽  
Diamond Coatings ◽  
Wear Properties ◽  
High Adhesion ◽  
Micro End Milling

Cobalt-cemented carbide micro-end mills were coated with diamond grown by chemical vapor deposition (CVD), with the purpose of micro-machining cemented carbides. The diamond coatings were designed with a multilayer architecture, alternating between sub-microcrystalline and nanocrystalline diamond layers. The structure of the coatings was studied by transmission electron microscopy. High adhesion to the chemically pre-treated WC-7Co tool substrates was observed by Rockwell C indentation, with the diamond coatings withstanding a critical load of 1250 N. The coated tools were tested for micro-end-milling of WC-15Co under air-cooling conditions, being able to cut more than 6500 m over a period of 120 min, after which a flank wear of 47.8 μm was attained. The machining performance and wear behavior of the micro-cutters was studied by scanning electron microscopy and energy-dispersive X-ray spectroscopy. Crystallographic analysis through cross-sectional selected area electron diffraction patterns, along with characterization in dark-field and HRTEM modes, provided a possible correlation between interfacial stress relaxation and wear properties of the coatings. Overall, this work demonstrates that high adhesion of diamond coatings can be achieved by proper combination of chemical attack and coating architecture. By preventing catastrophic delamination, multilayer CVD diamond coatings are central towards the enhancement of the wear properties and mechanical robustness of carbide tools used for micro-machining of ultra-hard materials.

Microstructure and corrosion resistance of pure titanium surface modified by double-glow plasma surface alloying

2013 ◽  
Vol 49 ◽  
pp. 1042-1047 ◽  
Author(s):  
Qiong Wang ◽  
Ping-Ze Zhang ◽  
Dong-Bo Wei ◽  
Ruo-Nan Wang ◽  
Xiao-Hu Chen ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Titanium Surface ◽  
Pure Titanium ◽  
Surface Alloying ◽  
Plasma Surface ◽  
Glow Plasma ◽  
Surface Modified ◽  
Plasma Surface Alloying

SURFACE Nb-ALLOYING ON 0.4C–13Cr STAINLESS STEEL: MICROSTRUCTURE AND TRIBOLOGICAL BEHAVIOR

2016 ◽  
Vol 23 (04) ◽  
pp. 1650017 ◽  
Author(s):  
SHENGWANG YU ◽  
KAI YOU ◽  
XIAOZHEN LIU ◽  
YIHUI ZHANG ◽  
ZHENXIA WANG ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Friction And Wear ◽  
Tribological Behavior ◽  
Alloyed Steel ◽  
Formation Mechanisms ◽  
Surface Alloying ◽  
Steel Microstructure ◽  
Glow Plasma ◽  
Nb Alloying ◽  
Plasma Surface Alloying

0.4C–13Cr stainless steel was alloyed with niobium using double glow plasma surface alloying and tribological properties of Nb-alloyed steel such as hardness, friction and wear were measured. Effects of the alloying temperature on microstructure and the tribological behavior of the alloyed steel were investigated compared with untreated steel. Formation mechanisms of Nb-alloyed layers and increased wear resistance were also studied. The result shows that after surface Nb-alloying treatment, the 0.4C–13Cr steel exhibits a diffusion adhesion at the alloyed layer/substrate interface and improved tribological property. The friction coefficient of Nb-alloyed steel is decreased by about 0.3–0.45 and the wear rate after Nb-alloying is only 2–5% of untreated steel.

High Energy Milling of WС-FeСr Cemented Carbide

2019 ◽  
Vol 799 ◽  
pp. 136-141
Author(s):  
Marek Tarraste ◽  
Jakob Kübarsepp ◽  
Kristjan Juhani ◽  
Märt Kolnes ◽  
Mart Viljus
Keyword(s):  
Particle Size ◽  
Ball Mill ◽  
Size Range ◽  
High Energy ◽  
Cemented Carbide ◽  
Cemented Carbides ◽  
Binder Phase ◽  
Metal Powders ◽  
Powder Mixtures ◽  
High Energy Milling

During production of cemented carbides hard and brittle tungsten carbide (WC) and ductile metal powders (mainly from Fe-group) are milled together. Complete milling results in a Gaussian distribution and narrow particle size range of the milled powder which promote the homogeneity and improve the properties of sintered composites. Cobalt, conventional metal employed in cemented carbides, possesses good comminution characteristics with WC powder. However, its toxicity and fluctuating price pushes researchers to find suitable alternatives and Fe-based alloys have shown most promising results. Cemented carbides with the Fe-Cr system as metal binder phase have potential to perform better than regular WC-Co composites in corrosive and oxidative environments. The goal of this paper was to prepare uniform cemented carbides powders with relatively high fraction of stainless Fe-Cr steel. To achieve a uniform powder mixture is a challenge at high ductile steel fraction. High energy milling (HEM) is a powerful technique for achieving (ultra) fine powder mixtures with narrow powder size range. HEM was carried out in a novel high energy ball mill RETSCH Emax. Milling in tumbling ball mill, which is the most widely used method, was employed for reference. Prepared powder mixtures were characterised in terms of particle size, size distribution and shape. In addition, powder mixtures were consolidated via spark plasma sintering to evaluate the effect of the milling method and the duration on the microstructure of final cemented carbide.

Wear Behaviour of Two Different Cemented Carbide Grades in Turning 316 L Stainless Steel

2018 ◽  
Vol 941 ◽  
pp. 2367-2372 ◽  
Author(s):  
Sara Saketi ◽  
Ulf Bexell ◽  
Jonas Östby ◽  
Mikael Olsson
Keyword(s):  
Grain Size ◽  
Stainless Steel ◽  
Wear Resistance ◽  
Wear Behavior ◽  
Cutting Tools ◽  
Cemented Carbide ◽  
Wear Behaviour ◽  
Binder Phase ◽  
Mechanical Wear ◽  
Cutting Insert

Cemented carbides are the most common cutting tools for machining various grades of steels. In this study, wear behavior of two different cemented carbide grades with roughly the same fraction of binder phase and carbide phase but different grain size, in turning austenitic stainless steel is investigated. Wear tests were carried out against 316L stainless steel at 180 and 250 m/min cutting speeds.The worn surface of cutting tool is characterized using high resolution scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDX), Auger electron spectroscopy (AES) and 3D optical profiler.The wear of cemented carbide in turning stainless steel is controlled by both chemical and mechanical wear. Plastic deformation, grain fracture and chemical wear is observed on flank and rake face of the cutting insert. In the case of fine-grained, the WC grains has higher surface contact with the adhered material which promotes higher chemical reaction and degradation of WC grains, so chemical wear resistance of the composites is larger when WC grains are larger. The hardness of cemented carbide increase linearly by decreasing grain size, therefore mechanical wear resistance of the composites is larger when WC grains are smaller.

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