Chemical modification of diamond surface was performed using benzoyl peroxide with CN group containing compound. When acetonitrile was used as the solvent for a radical reaction, the CN group was introduced on the diamond surface. On the other hand, when benzonitrile was used as the solvent for a radical reaction, no CN group was introduced on the diamond surface. Acetonitrile has an alkyl group in the structure. The radical species derived from benzoyl peroxide must abstract the hydrogen atom in the alkyl group, and then the radical species generated from acetonitrile should react with the diamond surface. Bensonitrile has no alkyl group in the structure. No hydrogen abstraction reaction, therefore, must proceed in the reaction process. This should be the reason for the nonintroduction of the CN group on the diamond surface.
Potentiostatic catholic electrodeposition of CdTe on gold-plated substrate was studied at 700°C or more using basic aqueous electrolytic baths in which Cd (II)-and Te (IV) -species were dissolving to form Cd (dien)22+ and TeO32- ions, respectively (dien: diethylenetriamine). The stoichiometry of CdTe electrodeposited can be controlled by changing the Cd (II)/Te (IV) concentration ratio, pH, and/or the diethylenetriamine content of the baths. Differences in the deposition behavior between two basic media with different complexing agents, diethylenetriamine and ammonia, were discussed thermodynamically with potential-pH diagrams drawn for the Cd-Te-dien-H2O and the Cd-Te-NH3-H2O systems. The deposition mechanism was also discussed in terms of interionic interaction between Cd (II) and Te (IV) species. The use of diethylenetriamine instead of ammonia made it possible to raise the temperature of electrolytic baths to 90°C, resulting in highly crystalline CdTe deposits without any post-treatment under a wide range of experimental conditions.
A relationship between corrosion potential and surface finish of Invar (Ni36%-Fe bal. alloy) etched in ferric chloride solutions was studied. The Invar was attached to a rotating disk electrode equipment. The rotation rate was set at 1600rpm in order to approximate the actual etching process. A principal ingredient of etchants was FeCl3. The concentration of FeCl3, FeCl2, free HCl and Ni2+ were 40 to 48mass%, 1.87±0.08mass%, 0.20±0.04m (molality) and 0.43±0.02m, respectively. The temperature was maintained at 60 to 80°C. We found a strong correlation between the surface finish and corrosion potential of Invar. When it was more noble than 200mV (SHE), the surface finish was smooth, while a rough finish was observed at less noble than 150mV. The difference of surface finish was shown distinctly in SEM photographs.
In the plasma nitride processing that uses direct current glow discharge, the sample is heated and ruggedness is generated on the sample surface because the ions in plasma bombard against the sample surface. To minimize the ruggedness, we heated the sample by an external electric heater during plasma nitride processing. The sample material was SACM 645 steel. NH3 gas was used for nitriding. We examined the generation of nitrified layers and surface roughness under various conditions of NH3 gas composition from 20 to 60%, nitriding temperature from 743 to 843K and nitriding time from 1.8 to 43.2ks. In general, higher nitriding temperature led to higher surface hardness. Moreover, the total case depth hardened by nitriding became from 0.2 to 0.3mm. Longer nitriding time led to higher surface hardness and the total case depth hardened by nitriding became from 0.075 to 0.35mm. No layer of nitrides of iron was generated until the NH3 gas composition became 40%. When the NH3 gas composition was 60%, 1.3μm layer was generated and the surface roughness was Rz 0.24μm. No nitride was identified by X-ray diffraction. However, higher NH3 gas composition led to larger half value width of α-Fe at peak. This suggested that nitrides mainly composed of minute nitride chromium were being precipitated.