The purpose of this study is to add a peelable property to the hard-coated glass pressing mold, by plating self-lubricant nickel-graphite composite film on the surface of the mold. In order to deposite a composite plating film, it is required that the surface of the depositing particle interact with depositing metal ions.Since the graphite particle more or less show hydrophobicity, it is necessary to introduce a hydrophilic functional group on the surface of the graphite particles. In this work, the graphite particles were heat-treated and acidic functional groups were introduced. The acidity or the pKa value of these groups was determined by the potentiometric titration method. It was clarified that the interaction between Ni2+ and the surface groups is enhanced with a pH increase of the plating solution. It is also clarified that the weight percentage of the graphite particles in the depositing film slightly increases with the solution pH.
In the present work, the authors studied the effects of thermal treatment temperature and thermal treatment duration on endowment of a hydrophobic property to TiO2 treated with alkyltrimethoxysilane solutions by a dry method. Also, the relationship between M value, a parameter of hydrophobic property, and fixation of ATMS onto TiO2 was examined. The main results obtained are as follows : (1) M values of TiO2 treated with n-BTMS and n-PTMS solutions increase with the increase in time elapsed, in another words, average polymerization degree, and finally reach a stagnant stage. The elevation of thermal treatment temperature and its duration also positively affect the M value of TiO2. On the other hand, the M value of TiO2 treated with n-DTMS was kept constant despite the change in thermal treatment conditions. (2) Amounts of fixed n-BTMS or n-PTMS onto TiO2 treated with these solutions increase with the increase in average polymerization degree. Since M value increases with the elevation of temperature even at the same level of fixation amount of coupling agent, it is assumed that the elevation of temperature affects the condensation onto the TiO2 surface. (3) ATMS Oligomer of lower molecular weight evaporated during the mixing and thermal treatment processes of TiO2 and ATMS solutions. This phenomenon was suppressed with the increase in average polymerization degree, resulting in the increase of fixed amount of ATMS onto TiO2. The decreasing sequence is expressed as n-PTMS>n-BTMS>n-DTMS. However, thermal treatment temperature is almost independent of vaporization amount.
Fabrication of the micro-disk electrode probe, which is convenient for micro-electrochemistry of localized surfaces or in small amounts of solution, has required special equipment or technical skills. In order to fabricate a micro-disk electrode probe simply, nickel electroless plating in a glass pipette was applied. After activation of the inside of a glass pipette heated and pulled off, nickel electroless-plating solution was successively introduced to deposit nickel in the pipette. Polishing the tip of the pipette and/or electroplating Ni, Cu or Pt obtained a disk surface with a diameter less than a few tens of micrometers. Cyclic voltammetry of the disk electrode showed a sigmoid curve and gave a limiting current which was identical with the theoretical value as a micro-disk electrode, indicating that this method was promising for fabrication of micro-disk electrodes. The electroless-plating micro-disk electrode was employed as a probe for scanning electrochemical microscopy to demonstrate its performance.
The interfacial pH during Ni plating from the Watts bath was measured by using a rotating ring disk electrode system where the Sb-plated ring electrode acts as a pH sensor. It was clarified that a linear relationship exists between the electrode potential of the Sb-plated ring electrode and the pH in the range from 2.0 to 6.5 and was also clarified that the Sb-plated rotating ring electrode could be used as a pH sensor for the electroplating process in these pH ranges. The Ni-Al(OH)3 composite film was electrodeposited by controlling current density under certain conditions, while the rise of interfacial pH during the plating process was estimated from the in situ pH measurement described above. The results of the SEM/EDX observations showed that minute particles, probably aluminum hydroxide, could be deposited with nickel from Al3+ contained in a non-turbid Watts bath under certain conditions determined by the interfacial pH measurement described herein.
The thermal spraying technique is widely used for various mechanical parts as a surface reforming technique. The operating environment is becoming increasingly harsh for superior mechanical performance, so the use environment of the sprayed coating has become severe. Therefore, the demand for technology that is checked non-destructively has become more insistent. For the purpose of this investigation, we reduced the thickness of the thermal sprayed coating by abrasion with blasting and used a bottom reflection echo in ultrasonic inspection for effective measurement of the quantity of abrasion of the thermal sprayed coating. The results obtained are summarized as follows. When the thickness of the thermal sprayed coating becomes thinner, the echo height increases. The reason is that the ultrasonic energy is absorbed by the thermal sprayed coating. The ultrasonic energy by which Al2O3 is absorbed compared to that of Fe-13Cr is small. The echo height when the thermal sprayed coating is in water is lower than when the thermal sprayed coating is in air. As mentioned above, the quantity of the thermal sprayed coating thickness could be estimated by ultrasonic inspection.
2-ethyl-1-hexanol increases the wettability of LiBr solution on a copper surface and improves the thermal efficiency of absorption refrigeration. The corrosion inhibition efficiencies for copper were investigated with various inhibitors in the LiBr solution containing 2-ethyl-1-hexanol. When 2-ethyl-1-hexanol was added in the LiBr solution, 1, 2, 3-benzotriazole (BTA), tolyltriazole (TTA) and 5-chlorobenzotriazole didn't show corrosion inhibition efficiency for copper. However, 2, 5-dimercapto-thiadiazole (DMTDA) and bismuthiol-II showed corrosion inhibition efficiency for copper in the LiBr solution containing 2-ethyl-1-hexanol. BTA is extracted by 2-ethyl-1-hexanol. Contrary to this bismuthiol-II and DMTDA are not extracted by 2-ethyl-1-hexanol, because bismuthiol-II and DMTDA are stable in the LiBr solution. DMTDA showed corrosion inhibition efficiency for copper in temperature range from 30ºC to 100ºC.