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Song J.,Xiamen Honglu Tungsten and Molybdenum Industry Co. | Wang W.,Xiamen Honglu Tungsten and Molybdenum Industry Co. | Ouyang M.,Xiamen Honglu Tungsten and Molybdenum Industry Co. | Ye D.,Xiamen Honglu Tungsten and Molybdenum Industry Co. | And 4 more authors.
Advances in Tungsten, Refractory and Hardmaterials IX - Proceedings of the 9th International Conference on Tungsten, Refractory and Hardmaterials | Year: 2014

Tungsten cathode is a consumable part in ion implanters, which is widely applied in semiconductor device fabrication. Traditionally wrought tungsten rods are machined to make the cathodes, with about 80% material being removed due to their complex geometry. More importantly, tungsten is a very hard and brittle metal, which is difficult for machining. Metal injection molding (MIM) can be a cost-effective alternative for manufacturing the cathode by net-shaping forming method. However, the densification of tungsten during sintering is difficult due to its high melting temperature. The demand of ultrafine tungsten powder for MIM is quite strong. A type of in-house developed submicron tungsten powder, therefore, has been used for MIM in this study. With the proper powder deagglomeration and binder system, the MIM tungsten cathode has been successfully developed. To solve the problem of long outgassing time and cross contamination during switching feed gases in the implantation process, which could be caused by the residual porosity (2%) of sintered cathode, a fully dense and high purity W layer has been coated on the surface of the cathode by chemical vapor deposition (CVD).


Lv Y.,Xiamen Honglu Tungsten and Molybdenum Industry Co. | Song J.,Xiamen Honglu Tungsten and Molybdenum Industry Co. | Liu J.,Xiamen Honglu Tungsten and Molybdenum Industry Co. | Yu Y.,Xiamen Honglu Tungsten and Molybdenum Industry Co. | And 2 more authors.
Advances in Tungsten, Refractory and Hardmaterials IX - Proceedings of the 9th International Conference on Tungsten, Refractory and Hardmaterials | Year: 2014

Chemical vapor deposition (CVD) is one of the principle methods to consolidate tungsten (W) to full density. A proper CVD-W process has been developed with a fast deposition rate higher than 0.5 mm/h. The high-purity, fully dense and columnar grain structure made it have a higher thermal conductivity and better thermal shock resistance than that of forged W, while the coefficients of thermal expansion for both types of W were similar. Mechanical properties such as bending strength and hardness have also been investigated. As a near-net shaping process for producing high purity and full dense W parts, CVD-W has been successfully to produce crucibles, irregular and capillary tubes, which cannot be realized by powder metallurgy methods. On the other hand, CVD-W has been employed as thick coating on the substrates such as graphite, copper, steel, aluminum etc. for various applications.


Song J.-P.,Xiamen Honglu Tungsten and Molybdenum Industry Co. | Shi T.,Xiamen Honglu Tungsten and Molybdenum Industry Co. | Yu Y.,Xiamen Honglu Tungsten and Molybdenum Industry Co. | Zhuang Z.-G.,Xiamen Tungsten Co.
Fenmo Yejin Cailiao Kexue yu Gongcheng/Materials Science and Engineering of Powder Metallurgy | Year: 2012

Molybdenum caps were prepared using molybdenum powder and wax-polymer binder mixture as feedstock. Feedstock was used by multiple recycling for 8 times to investigate the fluctuation of the maximum injection pressure, injection volume and green mass. The sinterability of the molded green bodies was also studied. The results show that the molybdenum feedstock has higher critical solid loading of 57% by volume fraction and good rheological property for injection. The developed binder has good stability and no evident decomposition is found during multiple recycling and injection. The fluctuation of green body mass can be controlled in the range of ±1.5%. The molybdenum caps with grain size less than 10 μm and density of 10.05 g/cm 3 are obtained after sintering, which is higher than the molybdenum cap fabricated by using commercial MIM molybdenum powder from America and Germany. The purity of molybdenum cap is higher than 99.95% and the content of C and O is 8×10 -6 and 10×10 -6, respectively. The density and purity both meet the industry operating requirement, and the stability of the process is good. The application to produce molybdenum caps has been industrialized.


Song J.,Xiamen Honglu Tungsten and Molybdenum Industry Co. | Shi T.,Xiamen Honglu Tungsten and Molybdenum Industry Co. | Yu Y.,Xiamen Honglu Tungsten and Molybdenum Industry Co. | Zhuang Z.,Xiamen Tungsten Co.
Proceedings of the World Powder Metallurgy Congress and Exhibition, World PM 2010 | Year: 2010

To fabricate the molybdenum powder injection molded products, the chemical reduced molybdenum powders have been treated by rod milling and jet milling respectively for deagglomeration. The obtained powders from jet milling have proper shape and size distribution for injection molding, indicated by low mixing torque and high critical solid loading about 57 vol. % in the mixing rheometer tests. Using a wax-polymer binder, a type of molybdenum feedstock, which has good moulding properties, has been developed. The application of this feedstock for producing molybdenum hats for microwave systems shows that the sintered parts have good stability, density dimensional accuracy, and microstructures. For comparison, two types of commercial ready-to-mix molybdenum powders special for injection molding are also investigated.


Yu Y.,Xiamen Honglu Tungsten and Molybdenum Industry Co. | Song J.,Xiamen Honglu Tungsten and Molybdenum Industry Co. | Liu J.,Xiamen Honglu Tungsten and Molybdenum Industry Co. | Zhuang Z.,Xiamen Tungsten Co.
Proceedings of the 8th International Conference on Tungsten, Refractory and Hardmaterials | Year: 2011

Metal injection molding has been utilized to fabricate a deep cup in W-1.5%La2O3 alloy with thin wall and high aspect ratio for the electrode application, including powder preparation, feedstock development, injection molding, debinding and sintering processes. The effects of particle size of tungsten powder on the feedstock preparation and sintering process have been investigated. Both the conventional sintering and activated sintering with Ni element have been tried to compare the relative density of sintered parts. The final parts with the relative density higher than 98% are obtained by activated sintering and using submicron tungsten powder. The microstructures and chemical elements of the final parts are analyzed.


Song J.,Xiamen Honglu Tungsten and Molybdenum Industry Co. | Qi M.,Xiamen Honglu Tungsten and Molybdenum Industry Co. | Zeng X.,Xiamen Honglu Tungsten and Molybdenum Industry Co. | Xu L.,Xiamen Honglu Tungsten and Molybdenum Industry Co. | And 2 more authors.
Proceedings of the Euro International Powder Metallurgy Congress and Exhibition, Euro PM 2011 | Year: 2011

W-10Cu is one of the most widely used materials for thermal management applications. The sinterability of this material is, however, not enough for reaching high density with normal powder. An in-house developed W-10Cu ultrafine composite powder has been employed for MIM. The torque rheology has been investigated to the feedstock with this ultrafine powder. The W-10Cu parts sintered at 1400 °C has reached relative density of 99%. The microstructure of sintered W-10Cu is homogenous and grain size for W is 2-3 μm. Thermal conductivity and coefficient of expansion are 215 W/mK and 6.7×10-6 /K respectively. A comparison of microstructure and properties between W-10Cu MIM parts and Cu infiltrated products has been presented.


Lian Y.,Southwestern Institute of Physics | Liu X.,Southwestern Institute of Physics | Cheng Z.,Southwestern Institute of Physics | Wang J.,Southwestern Institute of Physics | And 3 more authors.
Journal of Nuclear Materials | Year: 2014

Thick tungsten coating was produced by chemical vapour deposition (CVD) at a high deposition rate 0.6 mm/h. High heat flux tests using electron beam were performed to evaluate the thermal shock resistance of the developed CVD tungsten coating. The polished CVD tungsten surfaces were exposed to single shot disruption-like and repetitive ELM-like thermal shock loads at various temperatures and absorbed power densities. The thermal shock-induced damages were analysed by surface roughometer, scanning electron microscopy and light microscopy. Damage characteristics of the CVD tungsten were compared to that of the reference hot-rolled pure tungsten. The cracking thresholds and damage mechanisms of the CVD tungsten were presented and discussed. The tested results show that specific columnar grain structure of the CVD tungsten and base temperatures have significant influence on the crack formation and propagation direction towards the bulk material. © 2014 Elsevier B.V. All rights reserved.


Liu X.,Southwestern Institute of Physics | Lian Y.,Southwestern Institute of Physics | Chen L.,Southwestern Institute of Physics | Chen Z.,Southwestern Institute of Physics | And 4 more authors.
Journal of Nuclear Materials | Year: 2015

Abstract Transient heat loads, such as plasma disruptions and ELMs, could induce plastic deformations, cracking, melting, even fatigue cracks and creep of tungsten (W) surface. A high purity W, CVD-W coating, TiC dispersion strengthened and K doped tungsten alloys were tested in a 60 kW electron-beam facility by simulating the transient load events under different base temperatures. It was found that CVD-W, W-TiC and W-K alloys have higher crack thresholds than high purity W, meanwhile CVD-W is more sensitive to the crack disappearing at elevated base temperatures. On the other hand, repetitive pulse loading like ELMs can induce serious network cracks even the power density was quite lower than the crack threshold determined by a single shot. The ABAQUS code was used to simulate the crack behaviors of ITER grade pure W by a single shot and a FE-SAFE code was adopted to estimate the fatigue life under ELMs-like loads. A good agreement with experiment results was found. © 2014 Elsevier B.V.


Lian Y.,Southwestern Institute of Physics | Liu X.,Southwestern Institute of Physics | Xu Z.,Southwestern Institute of Physics | Song J.,Xiamen Honglu Tungsten and Molybdenum Industry Co. | Yu Y.,Xiamen Honglu Tungsten and Molybdenum Industry Co.
Fusion Engineering and Design | Year: 2013

Tungsten was coated on a W/Cu functionally graded material (FGM) by chemical vapor deposition technique (CVD), and then the tungsten coated tile was brazed on the CuCrZr heat sink with a cooling channel. The thickness of CVD-W was 2 mm deposited by a fast rate of about 0.7 mm/h. The features of the CVD-W coating including morphology, element composition and thermal properties were characterized. A tungsten coating with high density, purity and thermal conductivity is achieved. The bonding strength between the CVD-W layer and FGM was measured using bonding tensile tests. Thermal screening and fatigue tests were performed on the CVD-W mock-ups under fusion relevant conditions using an electron beam device. Experimental results showed that the CVD-W mock-up failed by melting of Cu beneath the tungsten layer under a high heat load of 14.5 MW/m2 and 30 s pulse duration. Thermal fatigue tests showed that the CVD-W mock-up could sustain 1000 cycles at a heat load of 11.7 MW/m2 absorbed power density and 15 s pulse duration without visible failure. © 2013 Elsevier B.V.


Zhao G.,Xiamen Honglu Tungsten and Molybdenum Industry Co. | Yu Y.,Xiamen Honglu Tungsten and Molybdenum Industry Co. | Peng F.,Xiamen Honglu Tungsten and Molybdenum Industry Co. | Song J.,Xiamen Honglu Tungsten and Molybdenum Industry Co.
International Powder Metallurgy Congress and Exhibition, Euro PM 2013 | Year: 2013

High-density tungsten/polymer composites were prepared by powder extrusion molding (PEM). The morphologies, mechanical properties, heat resistance and radiation shielding properties of these composites were investigated. The results indicated that the tungsten powders were homogeneously distributed within the polymer bindermatrixand anefficient polymer-filler interfacial network wasconstructed. The mechanical properties and heat resistance depended stronglyon the polymer type, which means the composites could be designed with highflexibilities. More importantly, the high-density tungsten/polymer composites exhibitedperfect radiation shielding performance, which fits theRoHS environmental standards. It is an ideal substitute materialfor lead, as well as forsintered heavy tungsten alloys for radiation shielding andbalancingfields.

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