مقاومت به فرسایش جرم های ریختنی دیرگداز

What Affects Erosion Resistance Of Refractory Castables?

چه چیزی مقاومت به فرسایش  جرم های ریختنی دیرگداز را تحت تأثیر قرار می دهد؟

ABSTRACT

The wear of refractory linings is often a critical problem in process units where transfer lines are subjected to high velocity gas stream containing solid particles. Knowledge regarding erosive wear of refractory linings under these conditions is restricted and, as consequence, the technological development is slow and, in general, carried out in an empirical way. The objective of the present work is to review relevant aspects related to erosive wear in industrial applications and to investigate the erosion resistance of refractory castables currently used by the aluminum industry and in petrochemical cracking units. Among the erosion variables tested are: the particle impingement angle, line pressure, particle size and hardness, the microstructure of the refractories, the binding agent content, type of aggregate, thermal history and porosity. It was found that the higher erosion was attained at 90º of impingement and decreased slightly when the angle was close to 30º. The results also pointed out that erosion was proportional to the particle velocity, its hardness and size. In addition, it was observed that the refractory erosion resistance is mostly affected by reducing the porosity.

 

رفتار سینترینگ و خواص دی الکتریکی سرامیک ها

Sintering behavior and dielectric properties of BaTiO3 ceramics with glass addition for internal capacitor of LTCC

رفتار سینترینگ و خواص دی الکتریکی سرامیک های BaTiO3 با افزودنی شیشه برای خازن داخلی LTCC 

ABSTRACT

The addition effects of ZnO–B2O3–SiO2 (ZBS) glass on both the sintering behavior and dielectric properties of BaTiO3 were investigated in developing low-temperature-fired BaTiO3-based ceramics for LTCC devices. X-ray diffractometer (XRD), scanning electron microscopy (SEM), and a dilatometer were used to examine the effect of ZBS glass on BaTiO3 densification and the chemical reaction between the glass and BaTiO3. The results indicate that ZBS glass can be used as a sintering aid to reduce the sintering temperature of BaTiO3 from 1300 to 900 ◦C without secondary phase formation. The dielectric properties of BaTiO3 with ZBS glass sintered at 900 ◦C show a relative density of 95%, a high dielectric constant of 994, and a dielectric loss of 1.6%.