Ti-N films of various compositions (N/Ti ratios of 1.09∼0.41, oxygen contents of 0.8∼6.5 at%, and carbon contents of 5.7∼9.4 at%) were prepared by ion plating onto silicon wafers, and the residual stresses of the films were investigated. In TiN single-phase films, the compressive stress reached a maximum at an N/Ti ratio of 1.0, and decreased as the N/Ti ratio increased or decreased of 1.0. At N/Ti ratios lower than 0.8, compressive stress again began to increase as Ti2N phase was deposited in the TiN, but decreased as α-Ti phase appeared in the films. At an N/Ti ratio of 0.41, the film consisted of Ti2N and α-Ti, and the residual stress in the film was tensile. Compressive stress increased with increasing oxygen or carbon contents of the film.
A study was conducted on the outgassing behavior from Ti thin films deposited by ion plating and on H2 adsorption on the clean or partially oxidized Ti film surface using thermal desorption spectroscopy (TDS). Desorption from the initial surface were mainly H2 molecules, which were considered to be generated by the thermal decomposition of titanium hydride compounds on the surface. Relatively small amounts of H2O, CO, and CO2 desorption were also detected. On the cleaned Ti film surface, adsorption of residual H2 gas from the vacuum vessel was observed. Analysis of TDS spectra showed that the reaction order of desorption is second order and the activation energy of desorption was estimated to be 1.52eV. The amount of H2 adsorption decreased as the O2 dose increased, which indicating that gettering of H2 occured only on the Ti metal surface and not on the oxide.
It is well known that resistance of stainless steel to atmospheric corrosion is influenced by the surface finish, and this has been attributed to Cr depletion near the surface and changes in surface film composition. There has, however, been little quantitative investigation of this phenomenon. The author has previously proposed a quick and easy electrochemical technique for measuring the depth profile of Cr near the surface of Fe-Cr and Fe-Cr-Ni alloys. In the present study, the depth profiles of Cr were measured by this method for SUS 304 stainless steel samples with various surface finishes. Accelerated atmospheric corrosion tests were also carried out to estimate the corrosion resistance of the various samples. These tests showed that the resistance to atmospheric corrosion changed in accordance with the Cr concentration at the surface of SUS 304 matrix. For example Cr concentration was 18.08% in the matrix, but was 15.7% with dry emery polishing and much rust formed on the surface. With wet emery polishing in 30% HNO3, however, it was 17.25% and virtually no rust formed.
The effects of surface morphology, silica codeposition and silane coupling treatment on the rubber adhesion of electroplated zinc have been studied using shear tensile tests and ESCA. No primer or adhesive was used at the interface of the rubber and the deposit. While the adhesion strength of rubber to the non-silane-coupled zinc deposit, with or without codeposited silica particles, was too small to measure, its adhesion strength to smooth and fan-shaped zinc deposits treated with 3-mercaptopropyltrimethoxysilane (3-MPS) was 2.7MPa and 3.4MPa, respectively. After shear tensile tests, however, adhesion failed commencing at the interface of the rubber and the deposit. When the fan-shaped zinc contained 1.6wt% of silica and was treated with 3-MPS, rubber adhesion strength increased to 5.3MPa, and the percentage of the area detached after the shear tensile tests was 70% at the deposit-to-rubber interface, and 30% at the rubber. ESCA analysis of electroplated zinc-silica composite surfaces with and without 3-MPS treatment indicated that some of the 3-MPS reacted with the silica particles and some bonded with OH radicals contained in the surface oxide of the zinc matrix.
It was found that bright tin-lead alloy deposits were obtained by the addition of polyoxyethyleneglycol (average molecular weight 3000) 1.0g/L and formaldehyde 0.6mL/L to pyrophosphate baths containing SnSO4 0.145M, Pb (CH3COO)2 0.055M and K4P2O7 0.5M. The further addition of EDTA to the bath suppressed the preferential deposition of lead and yielded fine-grained deposits at current densities of 10mA/cm2 or less. The optimum EDTA-to-lead concentration ratio for bright tin-lead alloy plating was from 1 to 1.5. The lead content of the deposits increased and the cathode current efficiency decreased with increasing concentrations of EDTA and K4P2O7 in the baths. The lead content of the deposits was virtually the same as that in the baths at current densities from 5 to 15mA/cm2. The cathodic polarization curve for lead deposition was more noble than that for tin without the EDTA and other additives, but shifted to a less-noble potential than that for tin deposition with their addition. It was concluded that the presence of EDTA suppresses the preferential deposition of lead.
To study the effect of beryllium on the reaction between solid iron alloys and liquid aluminum, specimens of three kinds of carbon steels, cast iron and Fe-0.43% Be alloy were immersed in molten baths of pure aluminum, Al-0.035% Be and Al-0.24% Be alloys at 770°C for 0.5∼128h. The thickness, composition and hardness of the reaction zone formed on the iron surfaces and the weight loss of the specimens due to corrosion by liquid aluminum were measured. Neither the weight loss of the iron specimens during the reaction nor the crystal structure in the reaction zone was significantly influenced by beryllium in the liquid aluminum or solid iron, but the thickness of the reaction zone decreased greatly with increasing beryllium content for immersion periods less than 8h. It was concluded that the presence of beryllium had no effect on the rate of formation of the Fe2Al5 alloy layer on the iron surface, but accelerated the rate of dissolution of the alloy layer into the liquid aluminum.
It has been found experimentally that the corrosion weight loss Y of cast irons in 0.5mol H2SO4 can be summarized by the equation. Y=0.0557X+4.503 Where X: ratio of the cathodic area (graphite) to the anodic area (iron).
Deposition efficiencies in the presence of magnetic fields increased with longer on-time and higher current density, but an supplementary, magnetic field effect appeared when off-time was prolonged. It was demonstrated that one of the magnetic field effects was due to the fact that Lorentz force caused replenishment of copper ions on the cathode. Magnetic fields can not be expected to produce any positive effects on pulse plating.