Page 73 - Synthesis of Functional Nanoparticles Using an Atmospheric Pressure Microplasma Process - LiangLiang Lin

Titanium Nitride Nanoparticles Synthesis - an Advanced Model Study towards Nitride Nanomaterial
The microplasma was characterized by optical emission spectroscopy and electrical measurements. A detailed study on chemical composition, microstructure and morphology of the synthesized products was carried out employing various analytical methods. Besides, comparisons of the process with preceding techniques were also carried out.
4.2 Experiment Section
4.2.1 Experimental
The microplasma setup for the synthesis of TiN nanoparticles was improved based on the setup of the chapter 3 by adding a H2 flow (line 3) to study the influence of H2 on precursor dissociation process and a N2 flow as the reacting gas (line 4). The detailed information of the setup can be referred to the Figure 2.2. In this study, TiCl4 (≥99.0%, Sigma-Aldrich) was employed as the precursor being injected into the plasma with continuous argon flow through the line 1. The bubbler vessel containing liquid precursors was installed on the top of an electronic scale (Sartorius, type R 300 S) to quantify the TiCl4 mass flow rate. A separate argon flow was used as a dilution gas to control the precursor concentration and maintain a constant total gas flow rate (line 2). All gas flows were individually controlled by mass flow controllers (MFCs) and mixed before being injected into the reactor for reaction. To prevent precursor condensation to pipelines, the oven temperature was set at 353.15 K during the experiments.
In a typical experimental procedure, the reactor was flushed with Ar before operation to remove oxygen impurities. The total gas flow rate was fixed at 110 sccm, enabling us to maintain a constant residence time. The plasma was switched on for a certain time (20 min) to ensure stable conditions before adding the precursor. After a desired process time (40 min), the plasma was switched off and the SS mesh was carefully taken out by tweezers, with obtained products collected into a small bottle by carefully knocking the mesh. The feeding rate of the precursor was quantified by measuring the precursor holder weight before and after experiment. Table 4.1 lists the processing parameters for the synthesis of TiN nanoparticles. In most cases, experiments were carried out at the condition 1 to produce TiN nanoparticles with N2 and TiCl4. Furthermore, the influence of H2 was also investigated by changing H2 partial concentrations.
Table 4.1 Processing parameters for the synthesis of TiN nanoparticles
Condition
Line 1 Line 2 (TiCl4 and Ar) (Ar)
(sccm) (sccm)
Line 3 (H2) (sccm)
0 1 3 5 10
Line 4 (N2) (sccm)
25 25 25 25 25
TiCl4 feeding rate (g/h)
0.0732 0.0732 0.0732 0.0732 0.0732
1 1.5 83.5
2 1.5 82.5
3 1.5 80.5
4 1.5 78.5
5 1.5 73.5
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