The xZnO-(1-x)alpha-Fe2O3 and xZrO2-(1-x)alpha-Fe2O3 nanoparticles systems have been obtained by mechanochemical activation for x=0.1, 0.3 and 0.5 and for ball milling times ranging from 2 to 24 hours. Structural and magnetic characteristics of the zinc and zirconium-doped hematite systems were investigated by X-ray diffraction (XRD), Mössbauer spectroscopy and conductivity measurements. Using the dual absorber method, the recoilless fraction was derived as function of ball milling time for each value of the molar concentration involved. As ZnO is not soluble in hematite in the bulk form, the present study clearly illustrates that the solubility limits of an immiscible system can be extended beyond the limits in the solid state by mechanochemical activation. Moreover, this synthetic route allowed us to reach nanometric particle dimensions, which makes these materials very important for gas sensing applications.

The salt damage such as the snow melting salts in winter or the sea salt particle flying in the coast region has significant effect on the corrosive environment of the automobile. Moreover, the corrosive environment of the automobile become more severe by the wet/dry cyclic condition, for example, a car gets wet with the splash water and dryness by the thermal loading while driving. On the other hand, the further application of the high strength stainless steel to the automobile parts is expected because it can contribute durability and lightening. Then, it is important to clarify the corrosion characteristic of this material under the salt damage environment. In this study cold rolled type304 stainless steel pipe with shot peening were used to investigate the corrosion property of high strength type304 stainless steel for automotive applications in a salt damage environment. The hardness of the pipe was about HV450, and a clear difference was not admitted in the thickness direction. A crevice was created between the outside of the pipe and an O-ring, and the pipe was applied stress by press fitting of another part. The corrosion property of the sample was evaluated in an automotive field test in Okinawa. Cracking from a corrosion pit was observed in the crevice. The Electron Prove Micro Analysis（EPMA） indicated that pitting corrosion was caused by chloride (from sea salt) concentrated in the crevice. The crack occurred in the residual compressive stress layer created by shot peening. In this regard, it was confirmed by the XRD analysis that about 85% of the metallographic structure had been transformed into the martensite. And the observation of the metallographic structure by the Electron Back Scatter Diffraction（EBSD） clarified the crystal grain was greatly transformed by the strong processing. It means that the accumulation of strain occurred. These two factors are considered to raise the receptivity to the crack generation of this sample. A crack generated at a corrosion pit was reproduced in a wet/dry cyclic corrosion test after one flash of artificial seawater. To investigate the crack generating mechanism, a corrosion pit was previously generated on the sample by cyclic corrosion test, after which a cathodic charge test in artificial sea water was done. Similar cracking from a corrosion pit was observed on the sample after this test. Therefore, the cracking is presumed to be Hydrogen Embrittlement-Stress Corrosion Cracking（HE-SCC）

In the past work of authors, a cold rolled type304 stainless steel pipe with shot peening was prepared. A crevice was created between the outside of the pipe and an O-ring, and the pipe was applied stress by press fitting another part. Cracking from a crevice corrosion pit was observed in a chloride environment, and it was presumed to be Hydrogen Embrittlement-Stress Corrosion Cracking（HE-SCC）. Provided that the crack is caused by HE-SCC､it is thought that hydrogen is generated by corrosion reaction and the SUS304 pipe absorbs it more than its critical level. Generally, the hydrogen distribution in the steel is analyzed in the condition that the hydrogen concentration of the environment is constant as the high-pressure hydrogen gas environment etc. In the case of HE-SCC described above, however, the hydrogen concentration is presumed to change with pitting growth, and there is no example of analysis in such condition. In this work, cyclic corrosion tests were conducted using the samples with no press-fitting part. The hydrogen density at the initiation point of crevice corrosion and cracking was estimated by following technique. First, the amount of hydrogen diffused from the corrosion pit was measured using Thermal Desorption Spectroscopy（TDS ）, and the number of pits was measured. Then, the average hydrogen quantity in a pit was derived. On the other hand, it is thought that hydrogen is generated by the hydrolysis of a metallic salt and the cathode reaction of the hydrogen ion in the pit. Therefore, the amount of the hydrogen is proportional to the quantity of corrosion amount. Then, assuming that pitting corrosion takes the form of half sphere shape and grows with time, the simulation model was made that the hydrogen absorbed and diffused from the pit surface with the development of corrosion. The profile of the hydrogen density in SUS304 from pit initiation till crack initiation was calculated based on this model. The calculated profile of the hydrogen density was compared with the amount of hydrogen measured by cyclic corrosion test. As a result, the hydrogen concentration at the crack starting point was derived 0.3ppm. At this density level, He-SCC can occur in high strength SUS304.

Measurements of nanoscale friction between silicon AFM tips featuring an in-situ solid state heater and silicon substrates (both with native oxide) were performed. The temperature of the heater was varied between room temperature and approximately 650 °C. For these temperatures and the silicon substrate, the temperatures at the point of contact are estimated to range from room temperature to approximately 120±20 °C. Experiments were carried out in ambient atmosphere (˜30% relative humidity) and under dry nitrogen. Tests under constant load revealed that in the presence of ambient, friction increased with heater temperature whereas it did not change in dry nitrogen. For experiments carried out for different tip velocities (40 to 7800 nm/s), friction decreased with velocity in ambient and did not change in dry nitrogen. Both trends can be explained by thermally-assisted formation of capillary bridges between tip and substrate and the kinetics of capillary condensation under ambient conditions.