金屬粉末已經廣泛應用於工業界，譬如粉末冶金、金屬射出成型、冷噴塗以及積層製造等。在眾多金屬粉末製造方式中，氣體霧化法具有可大量生產、低成本、粉末純度高、粒度大小及粒徑分佈可控、粉末形狀為球形以及快速冷卻等優點。目前應用於金屬粉末製造之氣體霧化器多為外混式限制型霧化器，一般而言操作於較大之氣體壓力範圍（大於20 bar）。本研究擬設計一應用於低氣體壓力之內部控制型霧化器，氣體在進入霧化器後可藉由由霧化器內部之漸縮漸擴流道達到超音速，此高速氣體並進一步被限制於霧化器之內部控制區域中，使得氣體之動能能更有效率地傳達至液體，增進霧化效率。本研究主要分為三個部分，分別為霧化機制之研究、水霧特性之研究以及金屬噴霧實驗。首先，在噴霧初始之暫態霧化機制研究中，發現若水先於空氣進入霧化器，則初始被碎化之液滴有撞擊控制區壁面之現象。另一方面，若是空氣先進入霧化器，則噴霧在水進入霧化器後隨即達到穩態。而由觀察噴霧穩態之霧化機制以及數值模擬之結果，可以發現當霧化器具有內部控制區時，超音速氣體在流經噴嘴時，因為其仍然在控制區內，使得氣體能夠持續膨脹而造成氣體速度能持續增加。此一速度提升可使得霧化效率得到進一步提升。然而增加控制區之擴張角則使得液體無法平均分佈於迴流區之邊界。而由水霧實驗之結果可以得知，在所有操作條件下，霧化器在輸送管出口處皆會產生負壓，而液體可藉由負壓進入霧化器而無須再加壓。結果亦顯示增加氣體壓力以及內混控制區之長度可使得負壓增加，進一步使得液體質量流率增加。液滴之粒徑則隨氣體壓力增加而降低。而藉由研究氣液質量比對於霧化粒徑之影響可得知增加內混控制區之長度亦可增加霧化效率。然而增加控制區之擴張角度則會造成霧化效率降低。在金屬噴霧實驗中，銅合金(C5212)之熔液被霧化後於噴霧塔內凝固並形成粉末，結果顯示在控制區長度為20 mm時，當氣體壓力從4 bar增加至6.5 bar，粉末粒徑(d50)可由67.29 μm降低至30.13 μm。結果亦顯示如要達到相同粒徑之粉末，具控制區之霧化器可操作在較低氣液質量比之霧化條件，顯示增加內部控制可有效提升霧化效率。而從SEM之粉末照片可發現所霧化之粉末形狀皆為球型。綜合以上結果，可以得知此新型內部控制型氣體霧化器在低氣體操作壓力下仍可得到細微之金屬粉末，適合用於金屬粉末之生產及製造。

Metal powders have been widely used in industries like powder metallurgy (PM), metal injection molding (MIM), cold spray (CS), and laser additive manufacturing (LAM). Among the various fabrication techniques for metal powder production, gas atomization is able to produce fine, spherical, and high purity powders with fine microstructure. Conventional gas atomization process for metal powder production is operated at high gas pressure, typically at gas pressure over 20 bar. In this research, a new gas atomizer with internal confinement has been designed for operation at low gas pressure. Atomizing gas enters the atomizer and reaches supersonic speed at the nozzle tip by flowing through an annular convergent-divergent flow channel in the atomizer. The gas is further confined in the atomizer by the internal confinement. Observation of spray patterns and investigation of the characteristics of water spray and performance of metal powder production have been carried out to understand the characteristics of the atomizer. Impingement of droplets on the inner surface of confinement is observed at the transient process owing to the pressurization of gas from ambient pressure to the setting pressure if gas enters the atomizer later than water. On the other hand, the spray immediately reaches steady state in the process where gas enters the atomizer first. From the observation of spray patterns at steady state and the simulation of gas flow behavior, it is found that the confinement of an atomizer allows the gas to have a further expansion, which means an increase in velocity. Increasing the expansion angle of confinement will increase the width of the recirculation zone and lead to a nonuniform liquid film on the boundary of the recirculation zone. The characteristics of water spray show that the pressure at the delivery tube is always negative and decreases with increasing gas pressure and confinement length. As a result, the water mass flow rate increases as gas pressure and confinement length increase. The median droplet size reduces with gas pressure, and better atomization efficiency can be achieved by increasing the confinement length. Increasing the expansion angle of the confinement will result in an increase in the pressure at the delivery tube tip and reduce atomization efficiency. In the melt experiments, copper alloy C5212 is atomized and particle sizes are reduced from 67.29 μm to 30.13 μm for the atomizer with 20 mm confinement as gas pressure increases from 4 bar to 6.5 bar. Atomizers with longer confinement can be operated at lower gas-to-melt ratio and have higher atomization efficiency. SEM photos show that the powders are all spherical in shape. In conclusion, the atomizer developed in this study performs impressively at low gas pressure and can be applied to metal powder production.

[1] Capus, J. M., “Chapter I - Introduction”, in Metal Powders (Fourth Edition). 2005, Elsevier Science: Oxford. p. 5-17.
[2] Kaysser, W. A., Weise, W., “Powder Metallurgy and Sintered Materials”, in Ullmann's Encyclopedia of Industrial Chemistry. 2000, Wiley-VCH Verlag GmbH & Co. KGaA.
[3] German, R., “Powder Metallurgy Science,” Metal Powder Industries Federation, 1994.
[4] Huppmann, W. J., Dalal, K., “Metallographic Atlas of Powder Metallurgy,” Schmid, 1986.
[5] Ertugrul, O., Park, H. S., Onel, K., Willert-Porada, M., “Effect of Particle Size and Heating Rate in Microwave Sintering of 316l Stainless Steel,” Powder Technology, 253: p. 703-709, 2014.
[6] Levina, D. A., Chernyshev, L. I., Mikhaylovskaya, N. V., “Powder Metallurgy in North America Continues to Grow,” Powder Metallurgy and Metal Ceramics, 45(7-8): p. 400-404, 2006.
[7] Kryachek, V. M., Levina, D. A., Chernyshev, L. I., “Powder Metallurgy Abroad,” Powder Metallurgy and Metal Ceramics, 46(7-8): p. 408-413, 2007.
[8] “The Italian Pm Industry,” Powder Metallurgy, 53(3): p. 180-181, 2010.
[9] Fedrizzi, A., Pellizzari, M., Zadra, M., “Influence of Particle Size Ratio on Densification Behaviour of Aisi H13/Aisi M3:2 Powder Mixture,” Powder Technology, 228: p. 435-442, 2012.
[10] Loh, N. H., Tor, S. B., Khor, K. A., “Production of Metal Matrix Composite Part by Powder Injection Molding,” Journal of Materials Processing Technology, 108(3): p. 398-407, 2001.
[11] German, R. M., “Markets Applications, and Financial Aspects of Global Metal Powder Injection Moulding (Mim) Technologies,” Metal Powder Report, 67(1): p. 18-26, 2012.
[12] Liu, Z. Y., Sercombe, T. B., Schaffer, G. B., “Metal Injection Moulding of Aluminium Alloy 6061 with Tin,” Powder Metallurgy, 51(1): p. 78-83, 2008.
[13] Moballegh, L., Morshedian, J., Esfandeh, M., “Copper Injection Molding Using a Thermoplastic Binder Based on Paraffin Wax,” Materials Letters, 59(22): p. 2832-2837, 2005.
[14] Kim, C. K., Son, C.-Y., Ha, D. J., Yoon, T. S., Lee, S., Kim, N. J., “Microstructure and Mechanical Properties of Powder-Injection-Molded Products of Cu-Based Amorphous Powders and Fe-Based Metamorphic Powders,” Materials Science and Engineering: A, 476(1–2): p. 69-77, 2008.
[15] Obasi, G. C., Ferri, O. M., Ebel, T., Bormann, R., “Influence of Processing Parameters on Mechanical Properties of Ti–6al–4v Alloy Fabricated by Mim,” Materials Science and Engineering: A, 527(16–17): p. 3929-3935, 2010.
[16] German, R. M., “Progress in Titanium Metal Powder Injection Molding,” Materials, 6(8): p. 3641-3662, 2013.
[17] Ahn, S., Park, S. J., Lee, S., Atre, S. V., German, R. M., “Effect of Powders and Binders on Material Properties and Molding Parameters in Iron and Stainless Steel Powder Injection Molding Process,” Powder Technology, 193(2): p. 162-169, 2009.
[18] Cheng, J., Wan, L., Cai, Y., Zhu, J., Song, P., Dong, J., “Fabrication of W–20 Wt.%Cu Alloys by Powder Injection Molding,” Journal of Materials Processing Technology, 210(1): p. 137-142, 2010.
[19] Contreras, J. M., Jiménez-Morales, A., Torralba, J. M., “Influence of the Morphology and Particle Size on the Processing of Bronze 9010 Powders by Metal Injection Moulding,” Materials Science Forum, 534-536: p. 365-368, 2007.
[20] Suri, P., Koseski, R. P., German, R. M., “Microstructural Evolution of Injection Molded Gas- and Water-Atomized 316l Stainless Steel Powder During Sintering,” Materials Science and Engineering: A, 402(1–2): p. 341-348, 2005.
[21] Lou, J., Li, Y. M., He, H., Li, L. J., “Effect of Atomisation Medium on Sintering Properties of Austenitic Stainless Steel by Eliminating Influence of Particle Shape and Particle Size,” Powder Metallurgy, 53(2): p. 112-117, 2010.
[22] Contreras, J. M., Jiménez-Morales, A., Torralba, J. M., “Fabrication of Bronze Components by Metal Injection Moulding Using Powders with Different Particle Characteristics,” Journal of Materials Processing Technology, 209(15–16): p. 5618-5625, 2009.
[23] Piotter, V., Gietzelt, T., Merz, L., “Micro Powder-Injection Moulding of Metals and Ceramics,” Sadhana, 28(1-2): p. 299-306, 2003.
[24] Zauner, R., “Micro Powder Injection Moulding,” Microelectronic Engineering, 83(4–9): p. 1442-1444, 2006.
[25] Liu, L., Loh, N. H., Tay, B. Y., Tor, S. B., “Microstructure Evolution of 316l Stainless Steel Micro Components Prepared by Micro Powder Injection Molding,” Powder Technology, 206(3): p. 246-251, 2011.
[26] Usama, M. A., Jeffrey, R. A., “A Review of Micro-Powder Injection Moulding as a Microfabrication Technique,” Journal of Micromechanics and Microengineering, 21(4): p. 043001, 2011.
[27] Dykhuizen, R. C., Smith, M. F., Gilmore, D. L., Neiser, R. A., Jiang, X., Sampath, S., “Impact of High Velocity Cold Spray Particles,” Journal of Thermal Spray Technology, 8(4): p. 559-564, 1999.
[28] Sakaki, K., “Cold Spray Process ~ Overview and Application Trends ~,” Materials Science Forum, 449 - 452: p. 1305-1308, 2004.
[29] Alkhimov, A. P., Papyrin, A. N., Kosarev, V. F., Nesterovich, N. I., Shushpanov, M. M., Gas-Dynamic Spraying Method for Applying a Coating. 1994, Google Patents.
[30] Jodoin, B., Raletz, F., Vardelle, M., “Cold Spray Modeling and Validation Using an Optical Diagnostic Method,” Surface and Coatings Technology, 200(14–15): p. 4424-4432, 2006.
[31] Li, C.-J., Li, W.-Y., “Deposition Characteristics of Titanium Coating in Cold Spraying,” Surface and Coatings Technology, 167(2–3): p. 278-283, 2003.
[32] Kang, H.-K., Kang, S. B., “Tungsten/Copper Composite Deposits Produced by a Cold Spray,” Scripta Materialia, 49(12): p. 1169-1174, 2003.
[33] Kim, H.-J., Lee, C.-H., Hwang, S.-Y., “Fabrication of Wc–Co Coatings by Cold Spray Deposition,” Surface and Coatings Technology, 191(2–3): p. 335-340, 2005.
[34] Wang, H.-T., Li, C.-J., Yang, G.-J., Li, C.-X., “Cold Spraying of Fe/Al Powder Mixture: Coating Characteristics and Influence of Heat Treatment on the Phase Structure,” Applied Surface Science, 255(5, Part 1): p. 2538-2544, 2008.
[35] Papyrin, A., Kosarev, V., Klinkov, S., Alkimov, A., Fomin, V., “Chapter 1 - Discovery of the Cold Spray Phenomenon and Its Basic Features”, in Cold Spray Technology, A. Papyrin, V. Kosarev, S. Klinkov, A. Alkimov, and V. Fomin, Editors. 2007, Elsevier: Oxford. p. 1-32.
[36] Gilmore, D. L., Dykhuizen, R. C., Neiser, R. A., Smith, M. F., Roemer, T. J., “Particle Velocity and Deposition Efficiency in the Cold Spray Process,” Journal of Thermal Spray Technology, 8(4): p. 576-582, 1999.
[37] Jang, S.-H., Park, S.-H., Han, J.-W., Lee, C.-H., Kim, H.-J., “Factors of Nozzle Design Affecting on Supersonic Flow in Cold Spray Process,” Materials Science Forum, 510-511: p. 1046-1049, 2006.
[38] Lee, H., Shin, H., Lee, S., Ko, K., “Effect of Gas Pressure on Al Coatings by Cold Gas Dynamic Spray,” Materials Letters, 62(10–11): p. 1579-1581, 2008.
[39] Jodoin, B., Ajdelsztajn, L., Sansoucy, E., Zúñiga, A., Richer, P., Lavernia, E. J., “Effect of Particle Size, Morphology, and Hardness on Cold Gas Dynamic Sprayed Aluminum Alloy Coatings,” Surface and Coatings Technology, 201(6): p. 3422-3429, 2006.
[40] Spencer, K., Zhang, M. X., “Optimisation of Stainless Steel Cold Spray Coatings Using Mixed Particle Size Distributions,” Surface and Coatings Technology, 205(21–22): p. 5135-5140, 2011.
[41] Gu, D. D., Meiners, W., Wissenbach, K., Poprawe, R., “Laser Additive Manufacturing of Metallic Components: Materials, Processes and Mechanisms,” International Materials Reviews, 57(3): p. 133-164, 2012.
[42] Li, X. P., Kang, C. W., Huang, H., Zhang, L. C., Sercombe, T. B., “Selective Laser Melting of an Al86ni6y4.5co2la1.5 Metallic Glass: Processing, Microstructure Evolution and Mechanical Properties,” Materials Science and Engineering: A, 606: p. 370-379, 2014.
[43] Olakanmi, E. O., Cochrane, R. F., Dalgarno, K. W., “Densification Mechanism and Microstructural Evolution in Selective Laser Sintering of Al–12si Powders,” Journal of Materials Processing Technology, 211(1): p. 113-121, 2011.
[44] Edwards, P., Ramulu, M., “Fatigue Performance Evaluation of Selective Laser Melted Ti–6al–4v,” Materials Science and Engineering: A, 598: p. 327-337, 2014.
[45] Pogson, S. R., Fox, P., Sutcliffe, C. J., O’Neill, W., “The Production of Copper Parts Using Dmlr,” Rapid Prototyping Journal, 9(5): p. 334-343, 2003.
[46] Fischer, P., Leber, H., Romano, V., Weber, H. P., Karapatis, N. P., André, C., Glardon, R., “Microstructure of near-Infrared Pulsed Laser Sintered Titanium Samples,” Applied Physics A, 78(8): p. 1219-1227, 2004.
[47] Krishna, B. V., Bose, S., Bandyopadhyay, A., “Low Stiffness Porous Ti Structures for Load-Bearing Implants,” Acta Biomaterialia, 3(6): p. 997-1006, 2007.
[48] Liang, Y.-J., Liu, D., Wang, H.-M., “Microstructure and Mechanical Behavior of Commercial Purity Ti/Ti–6al–2zr–1mo–1v Structurally Graded Material Fabricated by Laser Additive Manufacturing,” Scripta Materialia, 74: p. 80-83, 2014.
[49] Wycisk, E., Solbach, A., Siddique, S., Herzog, D., Walther, F., Emmelmann, C., “Effects of Defects in Laser Additive Manufactured Ti-6al-4v on Fatigue Properties,” Physics Procedia, 56: p. 371-378, 2014.
[50] Bi, G., Sun, C.-N., Chen, H.-c., Ng, F. L., Ma, C. C. K., “Microstructure and Tensile Properties of Superalloy In100 Fabricated by Micro-Laser Aided Additive Manufacturing,” Materials & Design, 60: p. 401-408, 2014.
[51] Denlinger, E. R., Heigel, J. C., Michaleris, P., Palmer, T. A., “Effect of Inter-Layer Dwell Time on Distortion and Residual Stress in Additive Manufacturing of Titanium and Nickel Alloys,” Journal of Materials Processing Technology, 215: p. 123-131, 2015.
[52] de Lima, M. S. F., Sankaré, S., “Microstructure and Mechanical Behavior of Laser Additive Manufactured Aisi 316 Stainless Steel Stringers,” Materials & Design, 55: p. 526-532, 2014.
[53] Järvinen, J.-P., Matilainen, V., Li, X., Piili, H., Salminen, A., Mäkelä, I., Nyrhilä, O., “Characterization of Effect of Support Structures in Laser Additive Manufacturing of Stainless Steel,” Physics Procedia, 56: p. 72-81, 2014.
[54] Li, Y., Gu, D., “Parametric Analysis of Thermal Behavior During Selective Laser Melting Additive Manufacturing of Aluminum Alloy Powder,” Materials & Design, 63: p. 856-867, 2014.
[55] Prashanth, K. G., Scudino, S., Klauss, H. J., Surreddi, K. B., Löber, L., Wang, Z., Chaubey, A. K., Kühn, U., Eckert, J., “Microstructure and Mechanical Properties of Al–12si Produced by Selective Laser Melting: Effect of Heat Treatment,” Materials Science and Engineering: A, 590: p. 153-160, 2014.
[56] Simchi, A., “Direct Laser Sintering of Metal Powders: Mechanism, Kinetics and Microstructural Features,” Materials Science and Engineering: A, 428(1–2): p. 148-158, 2006.
[57] Jiang, Z., Li, S., Zeng, J., Liao, X., Yang, D., “Effects of Powder Characteristics on Selective Laser Melting of 316l Stainless Steel Powder,” Advanced Materials Research 189 -193: p. 3664-3667, 2011.
[58] Lawley, A., “Atomization”, in Encyclopedia of Materials: Science and Technology (Second Edition), K.H.J. Buschow, R.W. Cahn, M.C. Flemings, B. Ilschner, E.J. Kramer, S. Mahajan, and P. Veyssière, Editors. 2001, Elsevier: Oxford. p. 387-392.
[59] Lawley, A., “Atomization: The Production of Metal Powders,” Metal Powder Industries Federation, 1992.
[60] Yule, A. J., Dunkley, J. J., “Atomization of Melts for Powder Production and Spray Deposition,” Oxford University Press, 1994.
[61] Angers, R., Tremblay, R., Dubé, D., “Formation of Irregular Particles During Centrifugal Atomization of Az91 Alloy,” Materials Letters, 33(1–2): p. 13-18, 1997.
[62] Zhao, Y. Y., “Considerations in Designing a Centrifugal Atomiser for Metal Powder Production,” Materials & Design, 27(9): p. 745-750, 2006.
[63] Plookphol, T., Wisutmethangoon, S., Gonsrang, S., “Influence of Process Parameters on Sac305 Lead-Free Solder Powder Produced by Centrifugal Atomization,” Powder Technology, 214(3): p. 506-512, 2011.
[64] Ho, K. H., Zhao, Y. Y., “Modelling Thermal Development of Liquid Metal Flow on Rotating Disc in Centrifugal Atomisation,” Materials Science and Engineering: A, 365(1–2): p. 336-340, 2004.
[65] Teunou, E., Poncelet, D., “Rotary Disc Atomisation for Microencapsulation Applications—Prediction of the Particle Trajectories,” Journal of Food Engineering, 71(4): p. 345-353, 2005.
[66] Kim, K. H., Lee, D. B., Kim, C. K., Hofman, G. E., Paik, K. W., “Characterization of U-2 Wt% Mo and U-10 Wt% Mo Alloy Powders Prepared by Centrifugal Atomization,” Journal of Nuclear Materials, 245(2–3): p. 179-184, 1997.
[67] Antony, L. M., Reddy, R., “Processes for Production of High-Purity Metal Powders,” JOM, 55(3): p. 14-18, 2003.
[68] Krajnikov, A. V., Likutin, V. V., Thompson, G. E., “Comparative Study of Morphology and Surface Composition of Al–Cr–Fe Alloy Powders Produced by Water and Gas Atomisation Technologies,” Applied Surface Science, 210(3–4): p. 318-328, 2003.
[69] Jack, H., Christopher, S., Neal, M., “Water Atomized Fine Powder Technology,” in Powder Metallurgy World Congress, Kyoto, Japan, 2000.
[70] Kikukawa, M., Matsunaga, S., Inaba, T., Iwatsu, O., Takeda, T., “Development of Spherical Fine Powders by High-Pressure Water Atomization Using Swirl Water Jet,” Journal of the Japan Society of Powder and Powder Metallurgy, 47: p. 453-457, 2000.
[71] Grandzol, R. J., Tallmadge, J. A., “Water Jet Atomization of Molten Steel,” AIChE Journal, 19(6): p. 1149-1158, 1973.
[72] Okamato, S., Sawayama, T., Seki, Y., “Kobe Steel Advances Water Atomized Powders,” Metal Powder Report, 51(3): p. 28-33, 1996.
[73] Neikov, O. D., “Chapter 5 - Atomization and Granulation”, in Handbook of Non-Ferrous Metal Powders. 2009, Elsevier: Oxford. p. 102-142.
[74] Neikov, O. D., Vasilieva, G. I., Sameljuk, A. V., Krajnikov, A. V., “Water Atomised Aluminium Alloy Powders,” Materials Science and Engineering: A, 383(1): p. 7-13, 2004.
[75] Krajnikov, A. V., Shmakov, Y. V., Thompson, G. E., “High Strength Weldable Al-Zn-Mg Base Alloys Produced by Water Atomisation,” Materials Science and Technology, 19(9): p. 1207-1214, 2003.
[76] Neikov, O. D., Mil’man, Y. V., Sirko, A. I., Samelyuk, A. V., Krainikov, A. V., Efimov, N. A., “Al-Fe-Ce Alloys Based on Water-Atomized Powders for High-Temperature Applications,” Powder Metallurgy and Metal Ceramics, 46(9-10): p. 429-435, 2007.
[77] Neikov, O. D., Milman, Y. V., Sirko, A. I., Sameljuk, A. V., Krajnikov, A. V., “Elevated Temperature Aluminum Alloys Produced by Water Atomization,” Materials Science and Engineering: A, 477(1–2): p. 80-85, 2008.
[78] Liu, Y., Niu, S., Li, F., Zhu, Y., He, Y., “Preparation of Amorphous Fe-Based Magnetic Powder by Water Atomization,” Powder Technology, 213(1–3): p. 36-40, 2011.
[79] Sato, T., “Rapid Quenching Qater Atomization Process for Making Amorphous Alloy Powders,” Scripta Metallurgica, 20(12): p. 1801-1806, 1986.
[80] Inoue, A., Kita, K., Ohtera, K., Kimura, H., Masumoto, T., “Al-Y-Ni Amorphous Powders Prepared by High-Pressure Gas Atomization,” Journal of Materials Science Letters, 7(12): p. 1287-1290, 1988.
[81] Liu, Y., Liu, Z., Guo, S., Du, Y., Huang, B., Huang, J., Chen, S., Liu, F., “Amorphous and Nanocrystalline Al82ni10y8 Alloy Powder Prepared by Gas Atomization,” Intermetallics, 13(3–4): p. 393-398, 2005.
[82] Dong, P., Hou, W. L., Chang, X. C., Quan, M. X., Wang, J. Q., “Amorphous and Nanostructured Al85ni5y6co2fe2 Powder Prepared by Nitrogen Gas-Atomization,” Journal of Alloys and Compounds, 436(1–2): p. 118-123, 2007.
[83] Huang, Z., Czisch, C., Schreckenberg, P., Büllesfeld, F., Fritsching, U., “Technical Note: Powder Production by Gas Atomization of Bioglass Melt,” Particle & Particle Systems Characterization, 22(5): p. 345-351, 2005.
[84] Nakayama, K. S., Yokoyama, Y., Wada, T., Chen, N., Inoue, A., “Formation of Metallic Glass Nanowires by Gas Atomization,” Nano Letters, 12(5): p. 2404-2407, 2012.
[85] Liu, X., Xie, H., Wang, L., Luo, J., Cai, Y., “Production of Fe-Si-Al-Ni-Ti Soft Magnetic Alloy Powder by Inert-Gas Atomization,” Procedia Engineering, 27: p. 1426-1433, 2012.
[86] Kim, J.-H., Lee, H., Hwang, K.-T., Han, J.-S., “Hydriding Behavior in Zr-Based Ab2 Alloy by Gas Atomization Process,” International Journal of Hydrogen Energy, 34(23): p. 9424-9430, 2009.
[87] Zhao, Y. F., Si, J. J., Song, J. G., Hui, X. D., “High Strength Mg–Zn–Ca Alloys Prepared by Atomization and Hot Pressing Process,” Materials Letters, 118: p. 55-58, 2014.
[88] Zhao, Y. F., Si, J. J., Song, J. G., Yang, Q., Hui, X. D., “Synthesis of Mg–Zn–Ca Metallic Glasses by Gas-Atomization and Their Excellent Capability in Degrading Azo Dyes,” Materials Science and Engineering: B, 181: p. 46-55, 2014.
[89] Reddy, R. C., Kiran, B. S., Sethi, V. C., Prakash, T. L., “Study on Oxygen Contamination During Atomisation of Solder Powders for Microelectronics,” Powder Metallurgy, 50(3): p. 228-231, 2007.
[90] Grenier, S., Tsantrizos, P., Allaire, F., “Plasma Atomization Gives Unique Spherical Powders,” Metal Powder Report, 52(11): p. 34-37, 1997.
[91] Czisch, C., Fritsching, U., “Atomizer Design for Viscous-Melt Atomization,” Materials Science and Engineering: A, 477(1-2): p. 21-25, 2008.
[92] Minagawa, K., Liu, Y., Kakisawa, H., Halada, K., “Production of Fine Metallic Powders by Hybrid Atomization Process,” JSME International Journal, Series A: Solid Mechanics and Material Engineering, 46(3): p. 260-264, 2003.
[93] Minagawa, K., Liu, Y., Kakisawa, H., Osawa, Y., Takamori, S., Halada, K., “Hybrid Atomization Process Applied to Fine Lead-Free Solder Powder Production,” Materials Transactions, 44(7): p. 1316-1319, 2003.
[94] Minagawa, K., Liu, Y., Kakisawa, H., Takamori, S., Osawa, Y., Halada, K., “Production of Fine Uniform Lead-Free Solder Powders by Hybrid Atomization,” Materials Science Forum, 426-432: p. 3341-3346, 2003.
[95] Minagawa, K., Kakisawa, H., Osawa, Y., Takamori, S., Halada, K., “Production of Fine Spherical Lead-Free Solder Powders by Hybrid Atomization,” Science and Technology of Advanced Materials, 6(3-4 SPEC. ISS.): p. 325-329, 2005.
[96] Minagawa, K., Kakisawa, H., Takamori, S., Osawa, Y., Halada, K., “Hybrid Atomization Method Suitable for Production of Fine Spherical Lead-Free Solder Powder,” Nukleonika, 51(SUPPL. 1): p. S83-S88, 2006.
[97] Liu, Y.-z., Minagawa, K., Kakisawa, H., Halada, K., “Melt Film Formation and Disintegration During Novel Atomization Process,” Transactions of Nonferrous Metals Society of China, 17(6): p. 1276-1281, 2007.
[98] Minagawa, K., Kakisawa, H., Halada, K., “Hybrid Atomization Method for Manufacturing Fine Spherical Metal Powder,” Materials Science Forum, 534-536: p. 69-72, 2007.
[99] Lagutkin, S., Achelis, L., Sheikhaliev, S., Uhlenwinkel, V., Srivastava, V., “Atomization Process for Metal Powder,” Materials Science and Engineering: A, 383(1): p. 1-6, 2004.
[100] Achelis, L., Uhlenwinkel, V., Lagutkin, S., Sheikhaliev, S., “Atomization Using a Pressure-Gas-Atomizer,” Materials Science Forum 534 - 536: p. 13-16, 2007.
[101] Achelis, L., Uhlenwinkel, V., “Characterisation of Metal Powders Generated by a Pressure-Gas-Atomiser,” Materials Science and Engineering: A, 477(1–2): p. 15-20, 2008.
[102] Li, X., Heisteruber, L., Achelis, L., Uhlenwinkel, V., Fritsching, U., “Spray Process Modeling in Metal Matrix Composite Powder Production,” 21(11): p. 933-948, 2011.
[103] Miller, S. A., Murphy, R. J., “A Gas-Water Atomization Process for Producing Amorphous Powders,” Scripta Metallurgica, 13(8): p. 673-676, 1979.
[104] Berkowitz, A. E., Grande, J. C., Miller, S. A., Murphy, R. J., Walter, J. L., “Structures and Properties of Powders of Fe75si15b10 Produced by Gas-Water Atomization,” Materials Science and Engineering, 62(2): p. 217-230, 1984.
[105] Walter, J. L., Berkowitz, A. E., “Effect of Cooling Rate on the Atomic and Crystal Structure of Rapidly Cooled Fe75si15b10,” Materials Science and Engineering, 67(2): p. 169-177, 1984.
[106] Fallavollita, J. A., Henein, H., Yuan, D., Method for Producing Droplets. 1997, Google Patents.
[107] Henein, H., “Single Fluid Atomization through the Application of Impulses to a Melt,” Materials Science and Engineering: A, 326(1): p. 92-100, 2002.
[108] Ellendt, N., Schmidt, R., Knabe, J., Henein, H., Uhlenwinkel, V., “Spray Deposition Using Impulse Atomization Technique,” Materials Science and Engineering: A, 383(1): p. 107-113, 2004.
[109] Entezarian, M., Allaire, F., Tsantrizos, P., Drew, R. A. L., “Plasma Atomization: A New Process for the Production of Fine, Spherical Powders,” JOM, 48(6): p. 53-55, 1996.
[110] Grenier, S., “Plasma Atomization Goes Commercial,” Metal Powder Report, 53(11): p. 26-28, 1998.
[111] Chen, Z., Chen, G., Yan, H., Chen, D., “Solid Atomization Technology and Process of Molten Metal and Alloy,” Materials Research Bulletin, 38(9–10): p. 1487-1492, 2003.
[112] Chen, D., Chen, J. H., Chen, G., Chen, G. L., Chen, Z. H., “Preparation of Fine Metal and Alloy Powders Via Gas Solid Dual Phase Atomisation Technology,” Powder Metallurgy, 50(4): p. 374-378, 2007.
[113] Akhlaghi, F., Esfandiari, H., “Solid-Assisted Melt Disintegration (Samd), a Novel Technique for Metal Powder Production,” Materials Science and Engineering: A, 452–453: p. 70-77, 2007.
[114] Singh, D., Dangwal, S., “Effects of Process Parameters on Surface Morphology of Metal Powders Produced by Free Fall Gas Atomization,” Journal of Materials Science, 41(12): p. 3853-3860, 2006.
[115] Aksoy, A., Ünal, R., “Effects of Gas Pressure and Protrusion Length of Melt Delivery Tube on Powder Size and Powder Morphology of Nitrogen Gas Atomised Tin Powders,” Powder Metallurgy, 49(4): p. 349-354, 2006.
[116] Unal, R., “The Influence of the Pressure Formation at the Tip of the Melt Delivery Tube on Tin Powder Size and Gas/Melt Ratio in Gas Atomization Method,” Journal of Materials Processing Technology, 180(1-3): p. 291-295, 2006.
[117] Ünal, R., “Investigation on Metal Powder Production Efficiency of New Convergent Divergent Nozzle in Close Coupled Gas Atomisation,” Powder Metallurgy, 50(4): p. 302-306, 2007.
[118] Ünal, R., “Improvements to Close Coupled Gas Atomisation Nozzle for Fine Powder Production,” Powder Metallurgy, 50(1): p. 66-71, 2007.
[119] Ünal, R., Aydın, M., “High Efficient Metal Powder Production by Gas Atomisation Process,” Materials Science Forum, 534-536: p. 57-60, 2007.
[120] Srivastava, V. C., Ojha, S. N., “Effect of Aspiration and Gas–Melt Configuration in Close Coupled Nozzle on Powder Productivity,” Powder Metallurgy, 49(3): p. 213-218, 2006.
[121] Allimant, A., Planche, M. P., Bailly, Y., Dembinski, L., Coddet, C., “Progress in Gas Atomization of Liquid Metals by Means of a De Laval Nozzle,” Powder Technology, 190(1–2): p. 79-83, 2009.
[122] Khatim, O., Planche, M. P., Dembinski, L., Bailly, Y., Coddet, C., “Processing Parameter Effect on the Splat Diameters of the Droplets Produced by Liquid Metal Atomization Using De Laval Nozzle,” Surface and Coatings Technology, 205(4): p. 1171-1175, 2010.
[123] Ricks, R. A., Clyne, T. W., “Bulk Production of Ultrafine Metallic Powder by High Pressure Gas Atomization,” Journal of Materials Science Letters, 4(7): p. 814-817, 1985.
[124] Naida, Y. I., Nichiporenko, O. S., “Atomization of Liquid Bronze and Properties of the Resulting Powders,” Soviet Powder Metallurgy and Metal Ceramics, 6(7): p. 532-535, 1967.
[125] Metz, R., Machado, C., Houabes, M., Pansiot, J., Elkhatib, M., Puyanē, R., Hassanzadeh, M., “Nitrogen Spray Atomization of Molten Tin Metal: Powder Morphology Characteristics,” Journal of Materials Processing Technology, 189(1–3): p. 132-137, 2007.
[126] Zhao, X., Xu, J., Zhu, X., Zhang, S., “Effect of Closed-Couple Gas Atomization Pressure on the Performances of Al-20sn-1cu Powders,” Rare Metals, 27(4): p. 439-443, 2008.
[127] Guo, S., Ning, Z. L., Zhang, M. X., Cao, F. Y., Sun, J. F., “Effects of Gas to Melt Ratio on the Microstructure of an Al–10.83zn–3.39mg–1.22cu Alloy Produced by Spray Atomization and Deposition,” Materials Characterization, 87: p. 62-69, 2014.
[128] Ouyang, H.-w., Chen, X., Huang, B.-y., “Influence of Melt Superheat on Breakup Process of Close-Coupled Gas Atomization,” Transactions of Nonferrous Metals Society of China, 17(5): p. 967-973, 2007.
[129] Veistinen, M. K., Lavernia, E. J., Abinante, M., Grant, N. J., “Effects of Geometry and Position of the Metal Delivery Tube on Ultrasonic Gas Atomization,” Materials Letters, 5(10): p. 373-379, 1987.
[130] Baram, J. C., Veistinen, M. K., Lavernia, E. J., Abinante, M., Grant, N. J., “Pressure Build-up at the Metal Delivery Tube Orifice in Ultrasonic Gas Atomization,” Journal of Materials Science, 23(7): p. 2457-2463, 1988.
[131] Cui, C., Cao, F., Li, Q., “Formation Mechanism of the Pressure Zone at the Tip of the Melt Delivery Tube During the Spray Forming Process,” Journal of Materials Processing Technology, 137(1–3): p. 5-9, 2003.
[132] Jeyakumar, M., Kumar, S., Gupta, G. S., “The Influence of Processing Parameters on Characteristics of an Aluminum Alloy Spray Deposition,” Materials and Manufacturing Processes, 24(6): p. 693-699, 2009.
[133] Zheng, B., Lin, Y., Zhou, Y., Lavernia, E., “Gas Atomization of Amorphous Aluminum: Part I. Thermal Behavior Calculations,” Metallurgical and Materials Transactions B, 40(5): p. 768-778, 2009.
[134] Zheng, B., Lin, Y., Zhou, Y., Lavernia, E., “Gas Atomization of Amorphous Aluminum Powder: Part Ii. Experimental Investigation,” Metallurgical and Materials Transactions B, 40(6): p. 995-1004, 2009.
[135] McCarthy, I. N., Adkins, N. J., Aslam, Z., Mullis, A. M., Cochrane, R. F., “High Speed Imaging and Fourier Analysis of the Melt Plume During Close Coupled Gas Atomisation,” Powder Metallurgy, 52(3): p. 205-212, 2009.
[136] Mullis, A. M., McCarthy, I. N., Cochrane, R. F., “High Speed Imaging of the Flow During Close-Coupled Gas Atomisation: Effect of Melt Delivery Nozzle Geometry,” Journal of Materials Processing Technology, 211(9): p. 1471-1477, 2011.
[137] Ouyang, H.-w., Huang, B.-y., Chen, X., Yu, W.-t., “Melt Metal Sheet Breaking Mechanism of Close-Coupled Gas Atomization,” Transactions of Nonferrous Metals Society of China, 15(5): p. 985-992, 2005.
[138] Mi, J., Figliola, R. S., Anderson, I. E., “A Numerical Simulation of Gas Flow Field Effects on High Pressure Gas Atomization Due to Operating Pressure Variation,” Materials Science and Engineering: A, 208(1): p. 20-29, 1996.
[139] Li, Z.-d., Zhang, G.-q., Li, Z., Zhang, Y., Xu, W.-y., “Simulation of Gas Flow Field in Laval Nozzle and Straight Nozzle for Powder Metallurgy and Spray Forming,” Journal of Iron and Steel Research, International, 15(6): p. 44-47, 2008.
[140] Antipas, G. S. E., “Modelling of the Break up Mechanism in Gas Atomization of Liquid Metals Part Ii. The Gas Flow Model,” Computational Materials Science, 46(4): p. 955-959, 2009.
[141] Zhao, X., Xu, J., Zhu, X., Zhang, S., “Effect of Atomization Gas Pressure Variation on Gas Flow Field in Supersonic Gas Atomization,” Science in China Series E: Technological Sciences, 52(10): p. 3046-3053, 2009.
[142] Zeoli, N., Gu, S., “Computational Validation of an Isentropic Plug Nozzle Design for Gas Atomisation,” Computational Materials Science, 42(2): p. 245-258, 2008.
[143] Tong, M., Browne, D. J., “Modelling Compressible Gas Flow near the Nozzle of a Gas Atomiser Using a New Unified Model,” Computers & Fluids, 38(6): p. 1183-1190, 2009.
[144] Zhao, W.-j., Cao, F.-y., Ning, Z.-l., Sun, J.-f., “Flow Field Simulation of Double Layer Atomizer,” Transactions of Nonferrous Metals Society of China, 19, Supplement 2: p. s485-s489, 2009.
[145] Aydin, O., Unal, R., “Experimental and Numerical Modeling of the Gas Atomization Nozzle for Gas Flow Behavior,” Computers & Fluids, 42(1): p. 37-43, 2011.
[146] Mi, J., Figliola, R. S., Anderson, I. E., “A Numerical Investigation of Gas Flow Effects on High-Pressure Gas Atomization Due to Melt Tip Geometry Variation,” Metallurgical and Materials Transactions B, 28(5): p. 935-941, 1997.
[147] Zhao, X.-m., Xu, J., Zhu, X.-x., Zhang, S.-m., “Effect of Protrusion Length of Melt Delivery Tube on Gas Flow Field for Supersonic Gas Atomization,” The Chinese Journal of Nonferrous Metals, 19: p. 967-973, 2009.
[148] Jeyakumar, M., Gupta, G. S., Kumar, S., “Modeling of Gas Flow inside and Outside the Nozzle Used in Spray Deposition,” Journal of Materials Processing Technology, 203(1–3): p. 471-479, 2008.
[149] Liu, H., Dandy, D. S., “Modeling of Liquid Metal Flow and Heat Transfer in Delivery Tube During Gas Atomization,” Materials Science and Engineering: A, 197(2): p. 199-208, 1995.
[150] Liu, H., Lavernia, E. J., Rangel, R. H., “An Analysis of Freeze-up Phenomena During Gas Atomization of Metals,” International Journal of Heat and Mass Transfer, 38(12): p. 2183-2193, 1995.
[151] Zeoli, N., Gu, S., “Computational Simulation of Metal Droplet Break-up, Cooling and Solidification During Gas Atomisation,” Computational Materials Science, 43(2): p. 268-278, 2008.
[152] Zeoli, N., Gu, S., Kamnis, S., “Numerical Modelling of Metal Droplet Cooling and Solidification,” International Journal of Heat and Mass Transfer, 51(15–16): p. 4121-4131, 2008.
[153] Tinoco, J., Widell, B., Fredriksson, H., Fuchs, L., “Modeling the in-Flight Events During Metal Spray Forming,” Materials Science and Engineering: A, 365(1–2): p. 302-310, 2004.
[154] Tong, M., Browne, D. J., “Direct Numerical Simulation of Melt–Gas Hydrodynamic Interactions During the Early Stage of Atomisation of Liquid Intermetallic,” Journal of Materials Processing Technology, 202(1–3): p. 419-427, 2008.
[155] Zeoli, N., Gu, S., “Numerical Modelling of Droplet Break-up for Gas Atomisation,” Computational Materials Science, 38(2): p. 282-292, 2006.
[156] Antipas, G. S. E., “Modelling of the Break up Mechanism in Gas Atomization of Liquid Metals. Part I: The Surface Wave Formation Model,” Computational Materials Science, 35(4): p. 416-422, 2006.
[157] Antipas, G., “Gas Atomization of Aluminium Melts: Comparison of Analytical Models,” Metals, 2(2): p. 202-210, 2012.
[158] Zeoli, N., Tabbara, H., Gu, S., “Cfd Modeling of Primary Breakup During Metal Powder Atomization,” Chemical Engineering Science, 66(24): p. 6498-6504, 2011.
[159] Putimtsev, B. N., “Effect of the Thermophysical Properties of Gases and Molten Metals on the Properties of Atomized Powders,” Soviet Powder Metallurgy and Metal Ceramics, 11(3): p. 171-175, 1972.
[160] Ünal, A., “Effect of Processing Variables on Particle Size in Gas Atomization of Rapidly Solidified Aluminium Powders,” Materials Science and Technology, 3(12): p. 1029-1039, 1987.
[161] Özbilen, S., “Influence of Atomising Gas Pressure on Particle Shape of Al and Mg Powders,” Powder Technology, 102(2): p. 109-119, 1999.
[162] Janowski, G. M., Biancaniello, F. S., Ridder, S. D., “Beneficial Effects of Nitrogen Atomization on an Austenitic Stainless Steel,” Metallurgical Transactions A, 23(12): p. 3263-3272, 1992.
[163] Zambon, A., “Nitrogen Versus Helium: Effects of the Choice of the Atomizing Gas on the Structures of Fe50ni30si10b10 and Fe32ni36ta7si8b17 Powders,” Materials Science and Engineering: A, 375–377: p. 630-637, 2004.
[164] Strauss, J. T., “Hotter Gas Increases Atomization Efficiency,” Metal Powder Report, 54(11): p. 24-28, 1999.
[165] Hopkins, W. G., “Fine Powders: The Heat Is on at Psi,” Metal Powder Report, 56(3): p. 20-24, 2001.
[166] “Gas Atomisation and the Economics of Blowing Hot and Cold,” Metal Powder Report, 59(6): p. 38-41, 2004.
[167] Lohner, H., Fritsching, U., Bauckhage, K., Melt Atomization by Heated Gases, in ILASS-Europe. 2002: Zaragoza.
[168] Wang, M. R., Chen, P. J., Yang, J. R., Chiu, J. S., Lin, T. C., Lai, T. S., “Combination of Spray Forming and Metal Powder Productions by the Internal Mixing Atomizer with a Substrate,” Materials Science Forum, 505-507: p. 1237-1242, 2006.
[169] Wang, M. R., Lin, C. T., Chen, P. J., “Development of Air-Assist Atomization for Production of Metal Powders,” in 15th Annual Conference on Liquid Atomization and Spray Systems-Asia (ILASS-Asia 2011), Kenting, 2011.
[170] Ting, J., Anderson, I. E., “A Computational Fluid Dynamics (Cfd) Investigation of the Wake Closure Phenomenon,” Materials Science and Engineering: A, 379(1–2): p. 264-276, 2004.
[171] John, J. E. A., “Gas Dynamics,” Allyn and Bacon, 1984.
[172] Zhao, X.-m., Xu, J., Zhu, X.-x., Zhang, S.-m., Zhao, W.-d., Yuan, G.-l., “Characterization of 17-4ph Stainless Steel Powders Produced by Supersonic Gas Atomization,” International Journal of Minerals, Metallurgy, and Materials, 19(1): p. 83-88, 2012.