Sintering of Al2O3-TiO2 Mixtures Obtained by High-Energy Ball Milling

2014 ◽  
Vol 87 ◽  
pp. 157-161 ◽  
Author(s):  
Alfeu Saraiva Ramos ◽  
Marisa Aparecida de Souza ◽  
Roberto de Oliveira Magnago ◽  
Claudinei dos Santos ◽  
Camila Aparecida Araujo da Silva ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Relative Density ◽  
Ball Milling ◽  
Molar Fraction ◽  
Weight Ratio ◽  
High Energy ◽  
Planetary Mill ◽  
High Energy Ball Milling ◽  
Water Evaporation ◽  
Energy Ball

In this work, the preparation of Al2O3-TiO2 ceramics by high-energy ball milling varying the molar fraction in 1:1 and 3:1 was investigated. The powder mixtures were processed in a planetary mill at 250rpm and a ball-to-powder weight ratio of 5:1, for 120min. Compacts were obtained by cold pressing at 100MPa. These specimens were heated at 1000◦C for 30min to promote the water evaporation, and subsequently sintered at 1500◦C for 240min. Samples were characterized by relative density and X-ray diffraction. Hardness and fracture toughness were determined by Vickers Indentation Method. The crystallite sizes were lower than 420 and 560Å in Al2O3-TiO2 and 3Al2O3-TiO2 powders, respectively. After sintering, XRD analysis indicates Al2TiO5 and Al2O3/Al2TiO5 as major crystalline phases for Al2O3-TiO2 and 3Al2O3-TiO2 compositions, respectively. The relative density of the Al2O3-TiO2 ceramics was higher than 90% in both compositions. However, hardness and fracture toughness results of 10.7GPa or 10.5GPa and 3.2MPa.m1/2 or 2.6MPa.m1/2 for Al2O3-TiO2 and 3Al2O3-TiO2 mixtures respectively, indicates that microstructure duplex composed by Al2O3 and Al2TiO5 grains lead to improvement of toughness of these ceramics.

Preparation of Al2TiO5-Al2O3 and Al2TiO5-Al2O3-TiO2 Ceramics by High-Energy Ball Milling and Sintering

2012 ◽  
Vol 727-728 ◽  
pp. 1193-1198 ◽  
Author(s):  
Pietro Carelli Reis de Oliveira Caltabiano ◽  
Marisa Aparecida de Souza ◽  
Rodrigo Fernando Costa Marques ◽  
Maria Gabriela Nogueira Campos ◽  
Luis Rogério de Oliveira Hein ◽  
...  
Keyword(s):  
Ball Milling ◽  
Molar Fraction ◽  
Weight Ratio ◽  
High Energy ◽  
High Energy Ball Milling ◽  
X Ray Diffraction ◽  
Electron Scanning Microscopy ◽  
Energy Ball ◽  
Rotary Speed ◽  
Sintered Materials

The present work reports on the preparation of Al2O3-TiO2 ceramics by high-energy ball milling and sintering, varying the molar fraction in 1:1 and 3:1. The powder mixtures were processed in a planetary Fritsch P-5 ball mill using silicon nitride balls (10 mm diameter) and vials (225 mL), rotary speed of 250 rpm and a ball-to-powder weight ratio of 5:1. Samples were collected into the vial after different milling times. The milled powders were uniaxially compacted and sintered at 1300 and 1500°C for 4h. The milled and sintered materials were characterized by X-ray diffraction and electron scanning microscopy (SEM). Results indicated that the intensity of Al2O3 and TiO2 peaks were reduced for longer milling times, suggesting that nanosized particles can be achieved. The densification of Al2O3-TiO2 ceramics was higher than 98% over the relative density in samples sintered at 1500°C for 4h, which presented the formation of Al2TiO5.

Nickel Silicides Synthesized by High Energy Ball Milling

2007 ◽  
Vol 353-358 ◽  
pp. 1625-1628 ◽  
Author(s):  
Gen Shun Ji ◽  
Qin Ma ◽  
Tie Ming Guo ◽  
Qi Zhou ◽  
Jian Gang Jia ◽  
...  
Keyword(s):  
Mechanical Alloying ◽  
Ball Milling ◽  
Milling Time ◽  
High Energy ◽  
Planetary Mill ◽  
High Energy Ball Milling ◽  
X Ray Diffraction ◽  
Microstructure Morphology ◽  
Energy Ball ◽  
Xrd Patterns

The high energy ball milling of Ni-50 atom % Si elemental powder mixtures was carried out using a planetary mill. X-ray diffraction (XRD) was used to identify the phase evolutions during the high energy ball milling period. The microstructure morphology of the powders milled different time was determined by field emission scanning electron microscope (FESEM). The beginning time of mechanical alloying was determined by back scattered electrons (BSE) images. The XRD patterns showed that the nickel peaks intensity and the silicon peaks intensity obviously decreased with milling time increased to 1 hour. BSE images revealed that nickel and silicon powders were not blended uniformly for 1 hour of milling. It was found that NiSi formed as the milling time increased to 5 hours, simultaneously, the nickel peaks and the silicon peaks almost disappeared. That means the obvious mechanical alloying started from 5 hours of milling. BSE images agreed with the result analyzed from XRD patterns. With the milling time further increased from 10 to 75 hours, the NiSi peaks decreased gradually, at the same time, the Ni2Si peaks appeared and then increased gradually.

Structure and Magnetic Properties of NdFeB Powder Prepared by Hydrogen Decrepitation and High-Energy Ball Milling

2014 ◽  
Vol 604 ◽  
pp. 262-266 ◽  
Author(s):  
Zoryana Mural ◽  
Lauri Kollo ◽  
Rainer Traksmaa ◽  
Kaspar Kallip ◽  
Joosep Link ◽  
...  
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Ball Milling ◽  
Magnetic Moments ◽  
Weight Ratio ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Final Particle ◽  
Energy Ball ◽  
Hydrogen Decrepitation

An ingot of NdFeB alloy was disintegrated by hydrogen decrepitation (HD). High-energy ball milling technique with hard metal milling elements and balls was employed to refine HD powders down to particle size optimum for magnet processing. The experiments were performed according to experimental plan to optimize the milling parameters regarding particle size, contamination and magnetic properties of the powder. The effect of milling time, speed of rotation, ball-powder weight ratio (BPR) and amount of wet agent was investigated. The highest influence was shown to be from attritor speed of rotation, ball-to powder ratio and combined effect of milling wet agent and rotating speed. Unified parameter of estimated number of total ball impacts was calculated, which allows predicting the final particle size of the powder at different milling speeds. Magnetic moments of powders were measured.

scholarly journals Effect of Ball Size on the Microstructure and Morphology of Mg Powders Processed by High-Energy Ball Milling

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1621
Author(s):  
Jesus Rios ◽  
Alex Restrepo ◽  
Alejandro Zuleta ◽  
Francisco Bolívar ◽  
Juan Castaño ◽  
...  
Keyword(s):  
Ball Milling ◽  
Morphological Evolution ◽  
Weight Ratio ◽  
High Energy ◽  
Milling Process ◽  
High Energy Ball Milling ◽  
X Ray Diffraction ◽  
Ball Size ◽  
Powder Particles ◽  
Energy Ball

Commercial powders of pure magnesium were processed by high-energy ball milling. The microstructural and morphological evolution of the powders was studied using scanning electron microscopy (SEM), energy dispersive spectrometry (EDX) and X-ray diffraction (XRD). From the results obtained, it was determined that the ball size is the most influential milling parameter. This was because balls of 1 mm diameter were used after a previous stage of milling with larger balls (i.e., 10 and 3 mm). The powder particles presented an unusual morphology with respect to those observed in the Mg-milling literature and recrystallization phenomena. Moreover, the result strongly varied depending on the ball-to-powder weight ratio (BPR) used during the milling process.

High-Energy Ball Milling and Hot Pressing of the Ni-48Ti-2Sn and Ni-45Ti-5Sn Powder Mixtures

2014 ◽  
Vol 802 ◽  
pp. 29-34
Author(s):  
Leandro Koji Kayano ◽  
Daniel Murusawa ◽  
Gilda Maria Cortez Pereira ◽  
Alfeu Saraiva Ramos
Keyword(s):  
Ball Milling ◽  
Hot Pressing ◽  
Weight Ratio ◽  
High Energy ◽  
Milling Process ◽  
High Energy Ball Milling ◽  
Wet Milling ◽  
Powder Mixtures ◽  
Energy Ball ◽  
Steel Balls

This work presents the results on the high-energy ball milling and hot pressing of Ni-48Ti-2Sn and Ni-45Ti-5Sn (at-%) powder mixtures. The milling process was performed in a planetary ball mill using stainless steel vial (225 mL) and hardened steel balls (19 mm diameter), rotary speed of 300 rpm, and a ball-to-powder weight ratio of 10:1. Samples were collected into the vial after different milling times: 60, 180 and 300 min. In the sequence, wet milling (isopropyl alcohol) was adopted up to 720 min in order to increase the powder yield into the vials. The as-milled and hot-pressed samples were characterized by X-ray diffraction, electron scanning microscopy, and energy dispersive spectrometry. Results indicated that the ductile particles were promptly cold-welded during the initial milling times. XRD patterns of the Ni-48Ti-2Sn powder mixture indicated that the peaks of Ni, Ti and Sn disappeared after milling for 3h. Following, peaks of NiTi and Ni4Ti3were preferentially formed during milling of Ni-Ti-Sn powders. A large amount of fine powders was yielded into the vial after wet milling for 720 min only. No significant carbon or oxygen contamination was detected by EDS analysis. Hot pressing produced homogeneous and dense samples which presented microstructures containing a large amount of the NiTi compound.

Effect of Ti Addition on the Fracture Toughness of Al-Ti-B Alloys Synthesized by High-Energy Ball Milling and Spark Plasma Sintering

2005 ◽  
Vol 486-487 ◽  
pp. 420-423
Author(s):  
Ji Hui Kim ◽  
Kwon Yeong Lee ◽  
Gyung Guk Kim ◽  
Seon Jin Kim
Keyword(s):  
Fracture Toughness ◽  
Ball Milling ◽  
Spark Plasma Sintering ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Neutron Shielding ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Energy Ball ◽  
Ti Addition

Al alloys containing boron or its compound are attractive for neutron shielding materials since boron exhibits high thermal neutron absorbing capability. However, poor fracture toughness and low ductility of boron compounds restrict their usage as structural materials. By adding Ti as a third element, it is expected to improve the toughness of Al-B alloys. The present study investigates the effect of the Ti addition on fracture toughness of the (Al+Xat%Ti)2at%B (X = 0.5, 1, 1.5 at%) alloy fabricated by high energy ball milling and spark plasma sintering (SPS). The SPS method was used to consolidate (Al+Xat%Ti)2at%B (X = 0.5, 1, 1.5 at%) alloy with the pressure of 50 MPa. Charpy impact tests showed that the fracture toughness of the 1 at%Ti added-alloy was 4 MPam1/2 , and that it was three times higher than that of Al-B alloys. Further reduction of the Ti addition down to 0.5 at% at 1.9 MPam1/2 or up to 1.5 at% at 2 MPam1/2 slightly decreased the fracture toughness. The microstructures of the present specimens were investigated by FE-SEM and TEM to describe the relationship with fracture toughness.

Preparation of Ni-Ti-Mo and Ni-Ti-Mo-Zr Alloys by High-Energy Ball Milling and Subsequent Hot Pressing

2012 ◽  
Vol 727-728 ◽  
pp. 233-238
Author(s):  
Gilda Maria Cortez Pereira ◽  
Marisa Aparecida de Souza ◽  
Tomaz Manabu Hashimoto ◽  
Vinicius André Rodrigues Henriques ◽  
Alfeu Saraiva Ramos
Keyword(s):  
Ball Milling ◽  
Hot Pressing ◽  
Weight Ratio ◽  
Graphite Crucible ◽  
High Energy ◽  
Milling Process ◽  
High Energy Ball Milling ◽  
Energy Ball ◽  
Rotary Speed ◽  
Steel Balls

This work discusses on the preparation of Ni-45Ti-5Mo, Ni-40Ti-10Mo and Ni-46Ti-2Mo-2Zr (at-%) alloys by high-energy ball milling and hot pressing, which are potentially attractive for dental and medical applications. The milling process was performed in stainless steel balls (19mm diameter) and vials (225 mL) using a rotary speed of 300rpm and a ball-to-powder weight ratio of 10:1. Hot pressing under vacuum was performed in a BN-coated graphite crucible at 900°C for 1 h using a load of 20 MPa. The milled and hot-pressed materials were characterized by X-ray diffraction, electron scanning microscopy, and electron dispersive spectrometry. Peaks of B2-NiTi and Ni4Ti3were identified in XRD patterns of Ni-45Ti-5Mo, Ni-40Ti-10Mo and Ni-46Ti-2Mo-2Zr powders milled for 1h. The NiTi compound dissolved small Mo amounts lower than 4 at%, which were measured by EDS analysis. Moreover, it was identified the existence of an unknown Mo-rich phase in microstructures of the hot-pressed Ni-Ti-Mo alloys.

Formation of Ni3Ta, Ni2Ta and NiTa by High-Energy Ball Milling and Subsequent Heat Treatment

2016 ◽  
Vol 869 ◽  
pp. 423-428
Author(s):  
Hanna Stefanni Nunes Benites ◽  
Bruna Pereira da Silva ◽  
Antonio Augusto Araújo Pinto da Silva ◽  
Belmira Benedita de Lima ◽  
Gilberto Carvalho Coelho ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Ball Milling ◽  
Weight Ratio ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Subsequent Heat Treatment ◽  
Mechanically Alloyed ◽  
Heat Treated ◽  
Energy Ball ◽  
Steel Balls

The present work reports on the formation of Ni3Ta, Ni2Ta and NiTa by high-energy ball milling and subsequent heat treatment. The elemental Ni-25Ta, Ni-33Ta and Ni-50Ta (at.-%) powder mixtures were ball milled under Ar atmosphere using stainless steel balls and vials as well as 300 rpm and a ball-to-powder weight ratio of 10:1. Following, the as-milled samples were uniaxially compacted and heat-treated under Ar atmosphere at 1100°C for 4h. The characterization of as-milled and heat-treated samples was conducted by means of X-ray diffraction, scanning electron microscopy, and energy dispersive spectrometry techniques. Supersaturated solid solutions were formed during ball milling of the Ni-25Ta, Ni-33Ta and Ni-50Ta powders. A large amount of Ni3Ta, Ni2Ta and NiTa was formed in the mechanically alloyed heat-treated Ni-25Ta, Ni-33Ta and Ni-50Ta alloys, respectively.

The Effect of Ball Milling on Properties and Sintering of Nanostructured TiB2

2021 ◽  
Vol 21 (7) ◽  
pp. 3934-3937
Author(s):  
Seong-Eun Kim ◽  
In-Jin Shon
Keyword(s):  
Relative Density ◽  
Ball Milling ◽  
High Energy ◽  
Planetary Mill ◽  
Sintering Behavior ◽  
High Energy Ball Mill ◽  
Crystallite Structure ◽  
Energy Ball ◽  
Short Time ◽  
High Frequency Induction

TiB2 powder was milled in a high-energy ball mill (Pulverisette-5 planetary mill) at 250 rpm for various time periods (0, 1, 4, and 10 h) and consolidated by the high frequency induction heated sintering (HFIHS). The effect of milling on the sintering behavior and crystallite size of TiB2 powders were investigated. A nanostructured dense TiB2 specimen with a relative density of up to 98% was readily achieved within very short time (two min). The ball milling effectively refined the crystallite structure of TiB2 powders and facilitated the subsequent consolidation. The sinter-onset temperature was reduced remarkably by the prior milling for 10 h. Accordingly, the relative density and mechanical properties of TiB2 compact increased as the milling time increased.

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