Porous NiTi alloy prepared from elemental powder sintering

1998 ◽  
Vol 13 (10) ◽  
pp. 2847-2851 ◽  
Author(s):  
Bing-Yun Li ◽  
Li-Jian Rong ◽  
Yi-Yi Li

An elemental powder sintering (EPS) technique has been developed for the synthesis of porous NiTi alloy, in which Ni and Ti powders are used as the reactants and TiH2 powder is added as a pore-forming agent and active agent. Effects of various experimental parameters (sintering temperature, sintering time, and TiH2 content) on the porosity, pore size, and pore distribution as well as phase composition in experimental alloys are investigated. It is found that in order to avoid the formation of carcinogenic pure Ni phase, the porous NiTi alloy should be synthesized over a temperature of 1223 K. This gives NiTi as the main phase without any elemental phase. Substitution of Ti by TiH2 is more economic and more favorable to obtain homogeneous porous NiTi alloy. A proper selection of initial powders, ball-milling, pressing, and sintering process makes it possible to achieve the porous NiTi alloy with desired properties.

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 438
Author(s):  
Shuwei Yang ◽  
Bingliang Liang ◽  
Changhong Liu ◽  
Jin Liu ◽  
Caisheng Fang ◽  
...  

The (1–x)Ca0.61La0.26TiO3-xNd(Mg0.5Ti0.5)O3 [(1–x)CLT-xNMT, x = 0.35~0.60] ceramics were prepared via microwave sintering. The effects of sintering temperature and composition on the phase formation, microstructure, and microwave dielectric properties were investigated. The results show that the microwave sintering process requires a lower sintering temperature and shorter sintering time of (1–x)CLT-xNMT ceramics than conventional heating methods. All of the (1–x)CLT-xNMT ceramics possess a single perovskite structure. With the increase of x, the dielectric constant (ε) shows a downward trend; the quality factor (Qf) drops first and then rises significantly; the resonance frequency temperature coefficient (τf) keeps decreasing. With excellent microwave dielectric properties (ε = 51.3, Qf = 13,852 GHz, τf = −1.9 × 10−6/°C), the 0.65CLT-0.35NMT ceramic can be applied to the field of mobile communications.


2012 ◽  
Vol 70 ◽  
pp. 142-145 ◽  
Author(s):  
Muhammad Hussain Ismail ◽  
Russell Goodall ◽  
Hywel A. Davies ◽  
Iain Todd

2011 ◽  
Vol 48-49 ◽  
pp. 331-334
Author(s):  
Cheng Long Gong ◽  
Jing Zhuo Wang ◽  
Yuan Feng

This paper introduces a computer control network system which can control sintering process of four PTFE molding furnaces accurately. System in-out signals such as sintering temperature, on-off signals of dial motor and aeration motor were connected to Lonworks via net nodes, and network variables were used to construct a configuration and interlinkage between the net nodes. We chose a combined-control strategy in which On-off control or Fuzzy-control or Fuzzy-PID control strategy were selected automatically, so the needs to sintering time, cooling speed, steady-state precision etc were accurately achieved.


2018 ◽  
Vol 2018 ◽  
pp. 1-9
Author(s):  
Chen Lu ◽  
Yue Wang ◽  
Xiaofan Wang ◽  
Jianfeng Zhang

As an effective and novel rapid sintering technology with the advantages of fast heating speed and short sintering time, SPS has been applied to the research and development of various materials. After sintering at 1325°C, Ti5Sn3and Sn occurred as impurities accompanying the synthesis of Ti2SnC with a raw powder mixture of Ti/Sn/C = 2/1/1 (molar ratio). But by addition of 0.2 molar Al, and further optimization of sintering parameters at 1400°C for 10 min, almost fully pure Ti2SnC was obtained with a clear layered microstructure. The reaction mechanism analysis suggests that this beneficial effect of Al could be attributed to the suppression of decomposition of Ti2SnC by formation of Ti2SnxAl1−xC solid solution at a high sintering temperature. The present study reports a novel route to synthesize Ti2SnC by PL-SPS with a self-designed graphite die, and Al was also proposed as a sintering aid to remove impurities.


2014 ◽  
Vol 541-542 ◽  
pp. 25-29
Author(s):  
Jin Qin ◽  
Gang Chen ◽  
Zhi Ming Du ◽  
Jia Hong Niu

The sintering temperature of 8YSZ (8mol% yttrium stabilized zirconia) is very high, usually above 1500°C. BAS (BaO-Al2O3-SiO2) microcrystalline glass can be used as sintering aids to reduce the sintering temperature of 8YSZ. In this research, large proportion (30-50wt%) BAS was added in 8YSZ to observe the influence of the sintering aids. The change rules of mechanical properties such as density test, bending strength and toughness in different material component and sintering process were researched. The results show that physical and mechanical performance improvement with the increase of sintering temperature and sintering time, density and bending strength decreases with the increase of BAS mass fraction. The optimal mechanical properties are obtained by sintering temperature 1300°C, sintering time 0.5h and 30wt% BAS.


2013 ◽  
Vol 11 (1) ◽  
pp. 283-291 ◽  
Author(s):  
Haochuan Zhao ◽  
Wenqi Zhong ◽  
Guanwen Zhou ◽  
Yingjuan Shao ◽  
Tiancai Wang ◽  
...  

Abstract A quantity of steel rolling sludge (SRS) produced in the rolling mill is harm to the environment and difficult to dispose. This article is devoted to study on utilization of SRS in sintering process. A sinter pot system with capacity of 75 kg was established. The sintering time, the flue gas temperature, the sintering temperature and the suction pressure in sintering process were measured. Besides the sinter quality, air pollutants discharged from the sintering process with the mass fraction of SRS ranging from 0 to 3% was investigated. The results showed that the CO2 concentration is corresponding to the sintering process, the SO2 concentration has a self-sustaining characteristic and the NOX concentration maintains stability. Increase in mass fraction of SRS leads to the decrease of sintering temperature, particle size, tumbler index and basicity of the sinter. Besides, the sintering time and the average concentration of NOX decrease first and then increase, while the suction pressure appears an opposite trend with increasing mass fraction of SRS. Moreover, the average concentration of CO2 and SO2 both decrease with increasing mass fraction of SRS, and the fuel consumption per sinter produced is the least when the mass fraction of SRS is 2%. Therefore, when the mass fraction of SRS was 2%, the sintering process had the best performance in consideration of sinter quality, emission of air pollutants and behaviors in sintering process.


2011 ◽  
Vol 337 ◽  
pp. 163-167 ◽  
Author(s):  
Yan Chen ◽  
M.M. Zhang ◽  
Z.Q. Liu

The magnetic abrasive prepared by sintering method, the aim is to change the internal structure of abrasive particles by sintering method, make the abrasive particles parceled on the surface of magnetic iron particles, and compared with the abrasive particles phase to get a kind of magnetic abrasive particles with high durability, strong magnetic, which can be magnetized in a magnetic field and improve processing efficiency and surface quality in magnetic abrasive machining. Sintering is used to prepare magnetic abrasive in this paper, to make iron particles, abrasive particles mixed with some binder, after suppression, drying, sintering, cooling, crushing and screening. This paper makes analysis for surface morphology and composition of the magnetic abrasive particles by scanning electron microscopy and discusses the effect that the abrasive particles size ratio, sintering time, sintering temperature on the magnetic abrasive, and the preparation of the magnetic abrasive process has been optimized.


2014 ◽  
Vol 46 (3) ◽  
pp. 307-313 ◽  
Author(s):  
N. Djordjevic ◽  
N. Obradovic ◽  
D. Kosanovic ◽  
M. Mitric ◽  
V.P. Pavlovic

Cordierite (MAS) is difficult to sinter because of the very narrow sintering temperature range (1300-1400?C). Because a low temperature process is desirable, it is necessary to find functional ads which can allow easier sintering process at lower temperature. The influence of MoO3 on the preparation process of cordierite ceramics was investigated. 2MgO-2Al2O3-5SiO2 was researched by sintering followed binary systems: MgO/MoO3, Al2O3/MoO3 and SiO2/MoO3 (all sintered at 850?C and 1100?C, sintering time 2h). Composition of these systems was 80 mass% of oxide and 20 mass% MoO3. The effects of sintering, the composition and morphology were followed by X-ray diffraction and SEM microscopy. It has been found that MoO3, beside liquid phase, forms intermediary unstable compounds with MgO and Al2O3, which is the significance information for further research. MAS ceramics were sintered with 20 mass% MoO3 at 1100?C, 1200?C and 1300?C, during 2h.


2021 ◽  
Vol 14 (3) ◽  
Author(s):  
Andhika Abdan Rahmanullah ◽  
Pawawoi Pawawoi ◽  
Djoko Hadi Prajitno

This research was conducted to determine the effect of the addition of Titanium (Ti) and the sintering temperature variation on MMC Cu-C alloys as reinforcing elements. The process of this research uses powder metallurgical method with an alloying technique in Mechanical Alloying using a Planetary Ball Mill (PBM) machine with a speed of 600 rpm for 2 hours, the ratio of powder to ball mill is 10: 1. The compacting process is carried out using dies 11 mm in diameter and compacting pressure of 90 Kg/cm2. The sintering process is carried out 3 times, with variations in sintering of 800oC, 900oC, and 1000oC with sintering time for 1 hour in the tube furnace in the argon gas vacuum environment. The number of samples used in this study amounted to 9 samples with variations in alloy and temperature sintering, consist of MMC Cu-C alloy with dopping of  Ti 0%, 0,5%, 1,5% (T=800 oC), MMC Cu-C with  dopping of Ti 0%, 0,5%, 1,5% (T=900 oC), and MMC Cu-C with dopping of Ti 0%, 0,5%, 1,5% (T=1000 oC). The tests included Vickers hardness testing, metallography testing, XRD testing, and SEM-EDS testing. The addition of Ti elements and varying sintering temperature had an effect on the hardness value of MMC Cu-C material with the highest hardness value in samples with 1.5% Ti alloy (800oC) which is 87.25 HV, and and the lowest porosity value is 2.491% in sample of 1.5% Ti (1000oC).


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