Effect of deposition parameters on micro-and nano-crystalline diamond films growth on WC-Co substrates by HFCVD

The characteristics of hot filament chemical vapor deposition（HFCVD） diamond films are significantly influenced by the deposition parameters, such as the substrate temperature, total pressure and carbon concentration. Orthogonal experiments were introduced to study the comprehensive effects of such three parameters on diamond films deposited on WC-Co substrates. Field emission scanning electron microscopy, atomic force microscopy and Raman spectrum were employed to analyze the morphology, growth rate and composition of as-deposited diamond films. The morphology varies from pyramidal to cluster features with temperature decreasing. It is found that the low total pressure is suitable for nano-crystalline diamond films growth. Moreover, the substrate temperature and total pressure have combined influence on the growth rate of the diamond films.

Effects of deposition parameters on HFCVD diamond films growth on inner hole surfaces of WC-Co substrates

Deposition parameters that have great influences on hot filament chemical vapor deposition (HFCVD) diamond films growth on inner hole surfaces of WC?Co substrates mainly include the substrate temperature (t), carbon content (φ), total pressure (p) and total mass flow (F). Taguchi method was used for the experimental design in order to study the combined effects of the four parameters on the properties of as-deposited diamond films. A new figure-of-merit (FOM) was defined to assess their comprehensive performance. It is clarified thatt,φandp all have significant and complicated effects on the performance of the diamond film and the FOM, which also present some differences as compared with the previous studies on CVD diamond films growth on plane or external surfaces. Aiming to deposit HFCVD diamond films with the best comprehensive performance, the key deposition parameters were finally optimized as:t=830 °C,φ=4.5%,p=4000 Pa,F=800 mL/min.

RemotesensingstudiesintheHaikouBayCalculationofthedepositionparameters

By making use of the distinguishing features of repetitive imagery of the same area by satellite remote sens-ing, a method of extracting water areas at different tidal levels from the images of bays at different times was adopted toestablish a calculating model for tidal surface and a method of finding a sum by layers was used to establish a calculatingmodel for the deposition parameter. Moreover, by making use of the calculating models for the deposition parameter andfor tidal level, the deposition parameter for the sea area less than 0 m was calculated for the Haikou Bay at two differentperiods of time: during the period of 1965 ￣ 1984 the total amount of deposits was 4 . 8 x 106 m3, and the sedimentationrate was 2 . 5 x 105 m3/a; during the period from 1984 to 1990, the total amount of deposits was - 8 . 9 x 105 m3 and thesedimentation rate was -1 . 5 x 105 m3/a.

Platinum-Iridium Alloy Films Prepared by MOCVD

Platinum-Iridium alloy films were prepared by MOCVD on Mo substrate using metal-acetylacetonate precursors. Effects of deposition conditions on composition, microstructure and mechanical properties were determined. In these experimental conditions, the purities of films are high and more than 99.0%. The films are homogeneous and monophase solid solution of Pt and Ir. Weight percentage of platinum are much higher than iridium in the alloy. Lattice constant of the alloy changes with the platinum composition. Iridium composition showing an up-down-up trend at the precursor temperature of 190~230℃ and the deposition temperature at 400~ 550℃. The hardness of Pt-Ir alloys prepared by MOCVD is three times more than the alloys prepared by casting.