Post-annealing temperatures

SPS has been confirmed to be a viable technique to synthesize PLZT transparent ceramics. An example is the preparation of PLZT(8/65/35) ceramics [227]. The PLZT powder was synthesized by using a wet-dry combination method. Due to the contamination of carbon from the graphite mold, the samples after the SPS sintering should be annealed in air or oxygen. Optical properties of the samples were affected by the SPS temperature, as well as the post-annealing temperature. It was found that 700 °C was the optimal sintering temperature when transmittance was considered. 

OSC with sol-gel-derived ZnO prepared using zinc acetate in 2-methoxyethanol with post annealing temperature below 200 C. The device structure of glass/ITO/ZnO/PCDTBT PC7oBM/MoOi/Ag achieved average PCE of 6.08%, 5.86% and 5.10% for post annealing temperatures of 200 C, 150 C and 130 °C respectively. This method used relatively low annealing temperatures for the ETL and demonstrated that the ETL produced can function efficiently in inverted OSCs. 

The major drawbacks to standard sol-gel synthesis include slow growth rate and the typically amorphous product, rather than defined crystals, which requires crystallization and post annealing steps. Growth rate and crystallization of the fabricated hybrid can be improved via solvothermal, reflux [224], sonication, and microwave [225] treatment. However, the air oxidation of CNTs (600 °C) and graphene (450 °C) may still be lower than MO crystallization temperature. Moreover, it has been shown that the MO coatings on CNTs can drastically affect their thermal oxidation, particularly with easily reducible metal oxides (e.g. TiOz = 520 °C, Bi203 = 330 °C) [180]. It appears that metal oxides can catalyze the oxidation of CNTs via a Mars van Krevelen mechanism, limiting the maximum temperature of their synthesis as well as applications (i.e. catalysis, fuel cells). 

Film Critical Current Densities Critical current densities of thin films have been reported by several hundreds of papers a few representative but by no means inclusive are noted here in addition to those mentioned above. Desirable attributes of thin films for technology are high transition temperature to zero resistance, high critical current, low substrate temperature during deposition, no high temperature post anneal, and atomically smooth surface without pinholes. A thermal coevaporation of yttrium, barium, and copper in an oxygen atmosphere have been deposited by Berberich (34) on substrates at 650°C with Tc s of 91 K on MgO and 89 K on SrTiOs without post anneal. Although critical currents of 106 A/cm2 were obtained at 4 K, values of 104 A/cm2 were found at 77 K. However,... 

The selectivity of the nickel(l 1 1) surface may thus be controlled by modification of the number of free step sites, and this notion was tested experimentally by blocking the steps with small amounts of silver (84). In other STM investigations it was found that when silver was deposited on nickelfl 1 1) at room temperature, the silver preferentially nucleated and grew as islands at the step edges. When this system was post-annealed to 800 K, the silver atoms were observed to become highly mobile and decorate all the step edges of nickelfl 1 1), as shown in Fig. 6b. 

Figure 14. Plots of the glass transition temperature of the soft segment phase, Tffs, Young s modulus E, and SAXS intensity, l(cps), vs. post-annealing time for a commercial polyester polyurethane (MDI/BD based), R53 (Hooker Chemical Company) (fixed s = 0.042 A 1 for SAXS data) (97).

Here RT growing of the ITO films and high temperature up to 700 °C post-annealing are studied. After the heat treatment of the film in air atmosphere there are some... 

Ceria only exhibits weak luminescence therefore, doping wifh rare earths such as Eu can enhance the visible emission required for imaging. Babu et al. reported the Eu + doped 10 nm ceria NPs s)mthesized by room temperature chemical precipitation and post annealing at 500 and 900 °C (Babu et al., 2008). A fraction of Ce exisfs in fhe ceria NPs, and if decreases after annealing. Emission intensity varies with the wavelength of excitation and observed transitions indicate the presence of Eu in different symmetry environments. 

In contrast to the dry methods, there are other conventional methods related to post heat treatment from precipitates from the aqueous solutions. The ambient aqueous routes and the hydrothermal methods at elevated temperature usually lead to rare earth precipitates like hydroxides, carbonates, instead of oxides. In fact, the hydrothermal treatment of rare earth oxide powders results in a hydration process to form hydroxides. Subsequently, the precursor could be used to produce rare earth oxide nanocrystals with post annealing at varied temperatures and in appropriate atmosphere. 

When solid state (Ba,Sr)C03 and TiO are formed, the formation of (Ba, Sr)Ti03 from these two phases by solid state reaction usually requires a temperature higher than 1100°C, which is unacceptable in the DRAM capacitor process. One factor to consider is that the actual chemical bond status of the carbon in the films may not be that of stable (Ba, Sr)C03 but can be more unstable which renders the elimination of the carbon or related impurities more feasible by a proper post-annealing than thermodynamics predicts. One must consider the atmosphere and surface status of the films during the aimealing... 

MOCVD process as well as the oxidation problem of the diffusion barrier, the low temperature MOCVD process is required which usually results in amorphous or weekly crystallized as-deposited thin films. Therefore, high temperature post-annealing is an absolute necessity. The upper limit temperature of the post-annealing is about 800°C considering the interdiffusion between the BST and electrodes at higher temperature and process integration issues such as degradation of the metal contact resistance. 

Luo, Cui and Li (1999) addressed the problem of temperature sensitivity of IBAD of ACPs and their subsequent crystallisation forming hydroxyapatite. Post-depositional annealing temperatures were decreased to 400 °C. The crystallisation of calcium phosphate coating is a hydroxyl ion diffusion-controlled process, thought to be the mechanism responsible for the decrease of the crystallisation temperature. The detailed study of the crystallisation process of calcium phosphate coatings shows that the crystallinity of the hydroxyapatite coating can be well controlled by adjusting the post-heat-treatment time. 

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