Huang Hongjun

A modified method for evaluation of materials containing volatile corrosion inhibitor

A systematic research on a modified method that was developed to evaluate the effectiveness of volatile corrosion inhibitor(VCI) materials was carried out. The metal specimen in size of 50 mm × 25 mm × 2 mm was level mounted on the top of a beaker by transparent adhesive tape and the assembly was placed in a constant temperature water bath and kept at approximately 40 °C to accelerate the vaporization of VCI and distilled water, which was placed at the bottom of the beaker at the same time. The experimental results show that the reproducibility of rust appearance and corrosion rate calculated by specimen’s mass loss is perfect. The outstanding characteristic of the rust appearance based on different VCI formula is discovered that is very important in studying the mechanism of VCI and the synergism of chemical reagent. The accelerated ratio is increased greatly as compared with the traditional method and the value is approximately 15 as compared with Shijiazhuang atmospheric environment corrosion test. The modified method is suitable for formula screening test and quick effectiveness evaluation of VCI materials.

Rheological properties of magnetorheological fluid prepared by gelatin — carbonyl iron composite particles

Gelatin — carbonyl iron composite particle was prepared by micro emulsion method. The analysis of scanning electron microscope(SEM) shows that the ultrafine particles are spheroids coated by gelatin, and the average sizes of particles are 3 – 10 µm. The specific saturation magnetization σs is 130.9 A · m2/kg, coercivity Hc is 0.823 A/m, and residual magnetism r is 4.98 Am2/kg for the composite particles. It is shown that the particles possess properties of soft magnetic. The yield stress of magnetorheological fluid (MRF) with composite particle reaches 70 kPa at 0.5 T magnetic induction. Magnetorheological effects are superior in lower magnetic field intensity and the subsidence stability of the MRF is excellent compared with pure carbonyl iron powder.