球磨过程对ZrO2粉末团聚的影响

本文采用两种不同粒度的工业３ｍｏｌ％Ｙ２Ｏ３－ＺｒＯ２粉为原料,研究了球磨过程对粉末粒度和ＺｒＯ２粉末团聚系数（ｄ５０／ｄＢＥＴ）的影响,实验结果表明：球磨能使大团聚粒子破碎,平均粒径减少,团聚系数降低,粉末粒度更均匀,随着球磨时间的延长,粉末平均粒径细化速度减慢,ＺｒＯ２团聚粒子破碎过程中将发生ｔ－ｍ相变。     

球磨过程对ZrO2粉末团聚的影响

本文采用两种不粒度的工业３ｍｏｌ％Ｙ２Ｏ３－ＺｒＯ２粉为原料，研究球磨过程对粉末粒度和ＺrＯ２粉末团聚系数的影响。实验表明：球磨能使大团聚粒子破碎，平均粒径减少 ，团聚系数降低，粉末粒度均匀， 球磨时间的延长，粉末平均粒径细化速度减慢。ＺrＯ２团聚粒子破碎过程将发生四方相t向单斜相m的相变。     

共沉淀—超临界流体干燥法合成CaO-ZrO_2复合氧化物超微粉体及其烧结性能研究 (Ⅰ)粉体的制备及性能表征

采用共沉淀—超临界流体干燥技术制备ＣａＯ－ＺｒＯ２复合氧化物超微粉体，并对其化学、结构及物理性能进行了表征。实验表明，超临界流体干燥法能很好地保留湿凝胶的空间网络状结构，有效地防止凝胶干燥过程中粒子间硬团聚现象的发生。该法制备的ＣａＯ－ＺｒＯ２复合氧化物超微粉体成分准确、均匀；粒径小、粒度分布范围窄；粒子的比表面大，活性高；而且ＣａＯ、ＺｒＯ２之间能够形成稳定的固溶体。     

乙二醇在络合物溶胶-凝胶法中的应用研究

采用ＥＤＴＡ（乙二胺四乙酸）溶胶－凝胶法制备了ＺｒＯ２－８％Ｙ２Ｏ３纳米粉末,并研究了乙二醇对粉末平均粒径和团聚体强度的影响机理。结果表明;在溶液中加入乙二醇,可取代氢键而参与ＥＤＴＡ络合物分子之间的聚合反应,改善凝胶稳定性,从而制得均匀透明的凝胶,并在一定程度上减少了硬团聚。     

纳米ZrO2的性能及其气敏性的研究

本文用沉淀法制备出平均晶粒尺寸在１８ｎｍ的单斜相ＺｒＯ２纳米粉末。并对其的开头和大小进行了透射电镜及激光散射分析,确认ＺｒＯ２粒子为球形,分散性较好,平均粒径为７０￣８０ｎｍ。本文着重了纳米级ＺｒＯ２细粉对乙醇的乞敏性能,结果表明,用纳米级ＺｒＯ２粒子制备的气敏元件对乙醇气体有好的敏感性,并且随着纳米粒子尺寸降低,对气体敏感性增强。     

球磨时间对β相氮化硅粉末及其烧结体特性的影响

对掺杂有Ｙ２Ｏ３的低纯度β－Ｓｉ３Ｎ４粉末进行了６至１００ｈ的球磨。调查了球磨时间对粉末和热压体各特性的影响。当球磨时间增加时，球磨粉末的平均粒度和微晶粒度减小，ＳｉＯ２碳、一些金属杂质和晶格变形增加，如果粉末表面重新形成，ＳｉＯ２的增加就可以被认为是由于球磨用液体中含的Ｈ２Ｏ发生机械化学反应所引起的。碳源来自球磨用液体和球磨容器两方面，Ａｌ和Ｍｇ的增加可以根据磨球的磨耗进行说明。由于球磨时间不同     

用CTAB/正己醇/水/盐反胶团体系制备纳米ZrO_2超细粉

利用ＣＴＡＢ／正己醇／水／盐反胶团体系，制备了含Ｙ２Ｏ３３％（摩尔百分比）的ＺｒＯ２超细粉末，运用冷冻蚀刻复形技术研究了反胶团的微观结构，用ＴＧ－ＤＴＡ、ＸＲＤ、ＴＥＭ、ＳＡＥＤ等分析手段对粉末及其前驱物进行了表征．实验结果表明，ＣＴＡＢ／正己醇／水／盐反胶团体系具有较大的溶盐量，其胶束微观结构良好．所获得的粉末为球形、粒度分布均匀、无硬团聚、粒径约３０ｎｍ的四方相二氧化锆．     

机械力活化合成超细ZrSiO4粉体及粉料的应用

把单斜晶系ＺｒＯ２和胶体ＳｉＯ２的混合料进行机械球磨，对混合料产生机械力活化作用，在较低温度（１２００℃）合成了超细的高活性ＺｒＳｉＯ４染料。研究了球磨时间对ＺｒＳｉＯ４生成率的影响。经１２０小时球磨的混合料，在１２００℃下煅烧后，ＺｒＳｉＯ４的生成率可达９５％以上。文中对合成的ＺｒＳｉＯ４粉料作为添加成分对一种陶瓷－金属封接料性能的影响进行了讨论。     

纳米ZrO2—Al2O3复合粉末注浆成型与烧结行为研究

平均粒径为２０ｎｍ的ＺｒＯ２添加５－１５ｖｏｌ％的粒径为２００ｎｍ的Ａｌ２Ｏ３粉末注浆成型与烧结特性表现出与普通微米及亚微米级粉末不同的特性浆料具有较低的含固量，粘度为５厘泊为５５ｗｔ％；浆料呈微弱触变性；生坯具有较低相对密度，仅为理论值的３５．５％，少量Ａｌ２Ｏ３促进复合材料的烧结，但也伴随着Ａｌ２Ｏ３晶粒异常长大。     

水热法制备Y_2O_3-CeO_2-ZrO_2超细陶瓷粉末

采用共沉淀－水热法制备了Ｙ２Ｏ３－ＺｒＯ２（ＹＺ）和Ｙ２Ｏ３－ＣｅＯ２－ＺｒＯ２（ＹＣＺ）超细陶瓷粉末（１０ｎｍ左右）．Ｘ射线衍射分析表明，二元钇和锆及三元钇、铈和锆的共沉淀氢氧化物，经水热处理后均可获得四方相复合氧化物．在１７０～２５０℃温度下进行水热处理，随着处理温度的提高，其氢氧化物的脱水速率加快，脱水更加完全，粉末粒度增大．有机添加剂如聚乙烯醇对水热产物可起到一定的分散作用．     

Solid‐phase preparation of ultra‐fine PA6 powder through pan‐milling

The engineering plastic polyamide 6 (PA6) was effectively pulverized to ultra‐fine powder through a sell‐made pan‐type milling equipment. A laser Diffraction Particle Size Analyzer and TEM were used to examine the particle size and the distribution of PA6 powder. The results show that the average particle size of PA6 was reduced to micrometer scale only after 15 milling‐cycles and reached 50–80 nm after 30 milling‐cycles. Pan milling decreased crystallinity of PA6 but did not affect its crystal type. Molecular weight and mechanical properties of PA6 dropped slightly during pan milling. The average particle size of PA6 powder could be controlled by adjusting processing conditions including milling time, temperature and the rotating speed of the milling pan.     

Study of the morphology and granulometry of polyethylene–clay nanocomposite powders

Medium‐density polyethylene (MDPE) matrix nanocomposites reinforced with different clay contents were produced by using a planetary ball mill. The morphology of all the milled samples, including pure polyethylene and the polyethylene–clay nanocomposites, was examined by scanning electron microscopy. To investigate the effects of milling time and clay content on the particle size of polyethylene powder, sieve analysis was used. The results showed that during milling, the regular shape of pure polyethylene powder converts into flake shapes and the average particle size of the powder increases upon increasing the milling time because the welding mechanism is predominant. Also, the presence of the clay can increase the maximum‐particle size, and increasing the clay content can decrease the milling time required to reach the same maximum particle size. J. VINYL ADDIT. TECHNOL., 2010. © 2009 Society of Plastics Engineers     

Calcium phosphate cements based on alpha-tricalcium phosphate obtained by wet method: Synthesis and milling effects

Calcium phosphate cements present many advantages for their use as bone substitute, among which biocompatibility and bioactivity. However, these cements generally have low mechanical strength compared to the bones of human body. This work aims to develop a method to produce calcium phosphate cements based on alpha-tricalcium phosphate and to evaluate the influence of milling time (0–16 h) on their particle size and mechanical properties. The obtained powder was characterized by particle size analysis and X-ray diffraction. The proposed method allowed to obtain highly pure alpha-tricalcium phosphate. The milling resulted in different average particle size, showing a decrease of around 83% with 16 h of milling. Specimens were prepared and evaluated by apparent density, microstructure by scanning electron microscopy and compressive strength. The variation of the average particle size influenced the compressive strength whose best result was obtained for the sample without additional milling.     

Nanocrystalline titanium powders by high energy attrition milling

The present investigation deals with the synthesis of nanocrystalline titanium powders by the high energy attrition milling of micron sized titanium powder in an inert atmosphere. Titanium powders of about 12 μm particle size were subjected to high energy attrition milling in an argon atmosphere. Selecting suitable milling parameters, nanosize (< 100 nm) titanium powders were obtained after 15 h of milling. An average particle size of 35 nm was obtained at 30 h of milling after which the particle size stabilized with continuation of milling to 75 h. The powders after milling for various durations were characterized by XRD, SEM, TEM, ICP-AES and DTA and these results are reported and discussed.     

Preparation and properties of AlON powders

Aluminum oxynitride (AlON) powders were synthesized using the raw materials of γ-Al₂O₃ and carbon black through the carbothermal reduction and nitridation process. The carbon content in the γ-Al₂O₃/C mixture and heating temperature were investigated. The AlON powders were synthesized by calcination for 2 h at 1750 °C when the carbon content in the γ-Al₂O₃/C mixture was 5.8 wt%. The particle size of powder is important to the transparency of ceramics, but the size of the synthesized powder was large. Therefore, a few methods, such as freeze-drying, ultrasonic dispersion, and liquid nitrogen ball milling, were used to reduce the particle size of powders. Among the three methods, liquid nitrogen milling had the best results.     

非水环境中球磨作用对改性SiO2晶体结构、粒度和Zeta电位的影响

以市售SiO2粉体为主要研究对象,采用X射线衍射线形分析、激光粒度分析和Zeta电位分析等表征手段,研究了球磨作用对改性SiO2晶体结构、粒度和Zeta电位的影响. 结果表明,SiO2分别经空气气氛中干磨、以N,N-二甲基甲酰胺(DMF)为球磨分散介质的湿磨、以二甲基甲酰胺(DMF)为球磨分散介质和以硅烷偶联剂KH-560为改性剂的湿磨后,其结构性质有显著差异,分别经过3 h球磨后,干磨、湿磨、添加10%硅烷偶联剂并湿磨和添加20%硅烷偶联剂并湿磨后SiO2平均晶粒尺寸分别为46.9, 31.4, 24.5和75.9 nm,其平均晶格畸变率分别为0.0253%, 0.0871%, 0.117%和0.063%,中位粒径分别为4.241, 1.586, 1.321和5.092 mm.     

粉体热压法制备As2Se3硫系玻璃研究

本研究尝试将As₂Se₃红外硫系透镜生产过程中产生的块体玻璃废料进行回收利用,首先将清洗后的块体玻璃废料球磨成粉体,然后采用粉体热压技术实现高光学质量As₂Se₃玻璃片的制备。研究了粉体粒度、热压参数对制备的As₂Se₃玻璃光学性能的影响,对比了粉体热压法和熔融淬冷法制备的As₂Se₃玻璃的性能,评估了通过粉体热压途径制备红外硫系玻璃的可行性。结果表明:随着球磨时间的延长,As₂Se₃玻璃粉体的平均颗粒尺寸逐渐减小,且颗粒尺寸的分布趋于更加均匀;使用平均颗粒尺寸为9.7 μm的粉体(球磨10 min),在压力为40 MPa、热压温度为250 ℃、热压时间为10 min的条件下获得的热压玻璃的致密度达到99.8%,其折射率与熔融淬冷法制备的玻璃的折射率接近(在10 μm波长的折射率差仅为0.003),在10 μm波长的透过率达61%(理论透过率为63.7%)。通过进一步提高玻璃粉体的纯度和尺寸均匀性,有望制备出与熔融淬冷法制备的玻璃性能相当的热压玻璃。     

Effect of powder milling routes on the sinterability and optical properties of transparent Y2O3 ceramics

In ceramic processing, the size distribution of the starting powder to a certain degree is inevitable. It is prerequisite to control the size distribution, which influences the fabrication of a sound green body featuring both smaller pores and a narrower pore structure for full-density sintering facilitated by the easier elimination of pores. The milling process was systematically investigated here to elucidate the effect of powder characteristics on the sinterability and transmittance of Y₂O₃ ceramics. Three types of powder sets having different width of particle size distribution (W_PSD) while keeping the same median size (D₅₀) were prepared by changing the milling condition. By means of narrowing the W_PSD in this research, pore free transparent polycrystalline Y₂O₃ with average grain size of 730 nm was successfully fabricated by hot-pressing at 1500℃, which is 100℃ lower than the previously lowest known sintering temperature.     

Optimized experimental design for natural clinoptilolite zeolite ball milling to produce nano powders

Nano powder of natural clinoptilolite zeolite was mechanically prepared by using a planetary ball mill. Statistical experimental design was applied to optimize wet and dry milling of clinoptilolite zeolite. To determine appropriate milling conditions with respect to the final product crystallinity, particle size and distribution, different milling parameters such as dry and wet milling durations, rotational speed, balls to powder ratio and water to powder ratio (for the wet milling) were investigated. Laser beam scattering technique, scanning electron microscopy and X-ray diffraction analyses were carried out to characterize samples. Results showed that larger than 1 mm particle size of clinoptilolite powder may mechanically be reduced into the size range of less than 100 nm to 30 μm by means of planetary ball milling.     

Synthesis of nanodiamond-reinforced aluminum metal composite powders and coatings using high-energy ball milling and cold spray

Nanodiamond-reinforced aluminum metal matrix composites (ND–Al MMC) powders were synthesized by means of high energy ball milling. We present a systematic study of the effect of various milling conditions on the structure and properties of the resulting MMC powders. The described method can be used to control important powder characteristics, including particle size and shape, Al crystal size and residual strain, and structural integrity and dispersion of the nanoparticle inclusions, a crucial requirement for subsequent powder consolidation. Raman spectroscopy was utilized for the first time to directly verify the structural integrity and the dispersion of ND in the Al matrix. For low ball-to-powder ratios (BPR), average particle size and size range of the ND–Al composite powders were found to decrease during milling, while the hardness increases. A BPR of 10:1, a milling time of 10 h, and a ND content of 10 wt.% were most effective in obtaining small powder particle sizes, small Al crystal sizes, and improved mechanical properties reaching a hardness of 3.46 GPa, a 210% increase over the pristine, untreated Al powder (1.10 GPa). Finally, we demonstrate that the as-produced composite powders are well-suited for low-temperature consolidation processing by fabricating the first cold-sprayed ND–Al MMC coating.