The sub-committee of materials engineer in chemical process industry has been composed of materials and its relating engineers in chemical companies, its retirees and professors of university, and have actively continued more than 15 years. The field material related problems proposed by the member are discussed seriously in this committee. The results of these discussion are summarized and are accumulated in “Q&A data base” that is carried at this committee’s homepage, and is applied by the members. Through these activities, the member's ability to solve the materials problem could be improved, and technical knowledge would be transferred and also the knowledge base would be prepared.
The slow strain rate testing (SSRT) on JIS Class 1, Class 2, Class 3, and Class 4 of commercially pure titanium (CP-Ti) was carried out in a hydrogen gas under high temperatures to 300℃ and high pressures to 75MPa. The degree of embrittlement in the hydrogen gas was evaluated from the tensile strength, the elongation and the reduction of area with respect to those measured in air at the same temperatures but under atmospheric pressure. It was revealed that the tensile strengths of the CP-Tis did not reduce regardless of their classes even in the hydrogen gas at a high pressure of 75MPa. The elongation and the reduction area at 100℃ rather increased in the high-pressure hydrogen gas than those in air.
An ultrathin two-dimensional polymer coating was prepared on a passivated iron electrode and then the passive film was healed by immersion treatment in 0.1 M NaNO3. The time required for passive film breakdown, tbd was measured by monitoring the open-circuit potential in 0.1 M solutions of four anions. The protective efficiencies of the passivated, polymer-coated and healed electrodes were extremely high, around 99.9% before tbd and hence, complete protection against corrosion of iron was accomplished, unless the passive film was broken down. On the other hand, the tbd values of the passivated Fe electrode, tbd0 have been determined in 0.1 M solutions of 14 different anions. In the present investigation, the tbd values of the passivated electrode covered with the polymer coating, tbd1 and those of the passivated, polymer-coated and healed electrode, tbd2 are estimated from tbd0. These values are discussed using classifications of anions based on the hard and soft acids and bases principle. Further, the effect of anion concentration on the tbd2 value is discussed.