Narrow Results

The deposition of lanthanum boride (LaB₆) thin films by the d.c. magnetron sputtering were studied. XRD, AFM and Stylus Profiler were used to characterize the properties of the deposited films. The XRD was used to study the crystallinity. The results of the XRD showed that the dominant crystal face is (100) face. The crystallinity decreased with the increased bias-voltage value, but the influence of bias-voltage on the films is different on different crystal face. The intensity (100) face was influenced by the bias-voltage more obviously than other faces except the influence of thickness. The diffraction peak maximal intensity of (100) face changed from 1256(on 0V) to 580(on -150V), but the intensity of (110) face changed from 614(on 0V) to 486(on -150V). The rel. int(100%) of (110) face changed from 38.70 to 74.52. The deposition rate decreased with the increased bias-voltage value, but the decreased was not obviously. The maximum and minimum of the deposition ratio were 17.53nm and 13.75nm respectively. Surface morphology of the films was studied by the AFM. The crystallite of the films was less than 50nm. The maximal roughness of the films decreased firstly and increased afterward, and it got the maximum on the -50V bias-voltage.

The Ni–Zn–P alloy coating has excellent physical and chemical properties that have been exploited for various industrial applications. Using sodium citrate as a complexing agent and lactic acid as a stabilizer, the effects of temperature and pH on the deposition rate and corrosion resistance of electroless plated Ni–Zn–P coating were studied. The results indicated that, when the temperature was 85${}^{\circ }$C, a good deposition rate was obtained with stable plating solution. pH value of 9.0 is preferred for the coating process by considering the stability of plating bath and deposition rate. The Ni–Zn–P alloy coating deposited with plating temperature of 85${}^{\circ }$C and bath pH of 9.0 has good quality, and a uniform and smooth surface texture without porosity.

In this study, the problems of the low deposition rate and bath instability in chemical deposition can be effectively solved by using the pulsed current-assisted chemical deposition process when preparing Ni–P alloy coating. Orthogonal experiments were designed by changing the average current density, pulse frequency and duty ratio of the pulses to study their effects on the deposition rate and hardness of the coatings. Compact Ni–P coating with uniform surface morphology and good performance was prepared by parameter optimization. The results show that our method can greatly improve the deposition rate while ensuring the surface quality and performance of the deposited layer.

The deposition of lanthanum boride (LaB₆) thin films by the DC magnetron sputtering were studied. XRD, AFM and Stylus Profiler were used to characterize the properties of the deposited films. The XRD was used to study the crystallinity. The results of the XRD showed that the dominant crystal face is the (100) face. The crystallinity decreased with the increased bias-voltage value, but the influence of bias-voltage on the films is different on different crystal faces. The intensity (100) face was influenced by the bias-voltage more obviously than other faces except the influence of thickness. The diffraction peak maximal intensity of the (100) face changed from 1256 (on 0 V) to 580 (on -150 V), but the intensity of (110) face changed from 614 (on 0 V) to 486 (on -150 V). The rel. int (100%) of the (110) face changed from 38.70 to 74.52. The deposition rate decreased with the increased bias-voltage value, but the decrease was not obvious. The maximum and minimum of the deposition ratio were 17.53 nm and 13.75 nm respectively. Surface morphology of the films was studied by the AFM. The crystallite of the films was less than 50 nm. The maximal roughness of the films decreased first and increased afterward, and the maximum was obtained on the -50 V bias-voltage.

The deposition kinetics and microstructure of chemical vapor deposition (CVD) of Nb on the Mo substrate at different deposition variables is investigated. The morphology of CVD Nb is columnar, it exhibits a strong preferred orientation and its growth direction is perpendicular to the substrate surface, the deposition rate and grain size increased with the increase of deposition temperature. The deposition rate conforms to the Arrhenius formula, the activation energy $(\mathrm{\Delta }Q)$ at high temperature and low temperature is 0.85 kJ/mol and 7.2 kJ/mol, respectively. The rate-limiting step for CVD Nb at high temperature is chemical reaction step, whereas that is the mass transport step at low temperature. Chlorination temperature has a weak influence on deposition rate and grain structure, the deposition rate and grain size of CVD Nb increased with the increase of the chlorine flow and hydrogen flow, the maximum deposition rate is $13.3\mathrm{\text{g}}\cdot {\mathrm{\text{h}}}^{-1}$, thus, the optimum deposition temperature is 1200${}^{\circ }$C, chlorination temperature is 350${}^{\circ }$C, hydrogen flow is 400 ml, chlorine flow is 200 ml.

A numerical study is needed to gain insight into the growth mechanism and improve the reactor design or optimize the deposition condition in chemical vapor deposition (CVD). In this study, we have performed a numerical analysis of the deposition of gallium arsenide (GaAs) from trimethyl gallium (TMG) and arsine in a vertical CVD reactor. The effects of operating parameters, such as the rotation velocity of susceptor, inlet velocity, and inlet TMG fraction, are investigated and presented. The three-dimensional model which is used in this investigation includes complete coupling between the thermal-fluid transport and species transport with chemical reaction.

The nano-SiC/Ni–P composite coatings (nSNCCs) were fabricated on the surface of Glass substrates with the assistance of different electromagnetic fields. Then, the deposition rates of the nSNCCs were calculated by the weighing method. Morphology, chemical composition and crystal structure were characterized by SEM, EDS and X-ray diffraction (XRD), respectively. Experimental results show that the nSNCCs are all built by the accretion of spherical co-deposition product of Ni solid solution and nano-SiC particulates. Moreover, at the same plating time, the deposition rates of the nSNCCs increase with the increasing magnetic strength, and reach the peak by 17.5g/h$\cdot$m${}^{-2}$. Meanwhile, the spherical particle size and the spaces between spherical co-deposition decrease, which result in the formation of the dense layers. The addition of magnetic fields in preparation process not only promotes the deposition of the nSNCCs, but also has a great influence on the orientation of the deposited products, which is favorable for the formation of a compact and uniform composite coating.