Table 5. Comparison of properties of Type 304 with those of stainless steels to save Ni.

A gas tunnel-type plasma jet has a higher temperature than any other plasma jets; a high-power stabilized plasma beam can be easily obtained. Moreover, it is possible to inject various materials from the center electrode toward the center of this plasma beam. These properties of the gas tunnel-type plasma jet apparatus are of great advantage to the application to the thermal spraying of high melting point materials such as ceramics. The fundamental characteristics of this new type of plasma spraying apparatus were determined through experimentation, and a variety of ceramic coatings produced using this apparatus were studied. Since this system is very effective in heating and melting sprayed powder, high-quality ceramic coatings can be easily produced even at a small power using argon as the working gas. At 30 kW or more, the Vickers hardness of the various ceramic coatings is 30% greater than that produced with a conventional-type plasma spraying apparatus. For example, a Vickers hardness value of 1200 has been achieved for Al2O3 coatings.

The analogy between magnetic froth (cellulardomain patterns ingarnet films) and the two-dimensional soap froth is used to develop an elementary model for the former system. Simulations are performed using this model: they have many features in common with recent experimental results and can be further illuminated by simple calculations in the spirit of mean-field theory. An analysis of topological cell statistics is also presented.

Internal friction of Fe-Cr-Mn alloys have close relations with chemical compositions, constituent phases and cold work degree. In Fe-Cr-Mn alloys, phases are composed from y, E and a depending on chemical compositions. In solution annealed specimens, internal friction was higher when a phase was included. This suggests that a phase behaves as ferromagnetic phase and also introduces fresh dislocation surrounding it. In cold worked specimens, internal friction increases dependent on cold work degree and it was became highest when E phase is maximum. This result suggests that the stacking fault energy is minimum in this case, and the extended half dislocations are more mobile than other cases. In cold worked specimens the contribution of a phase was negligible. This alloy has damping capacity higher than 1%, with high strength (more than 1000 MPa) and high corrosion resistance.

No abstract