Effects of slurry pack cementation temperature on microstructure and wear resistance of Ti-Al co-deposited coating on copper plated nickel layer

In order to improve the wear resistance properties of copper substrate, a layer of electroplated nickel was firstly deposited on copper substrate, subsequently these electroplated specimens were treated by slurry pack cementation process with a slurry pack cementation mixture composed of TiO2 as titanizing source, pure Al powder as aluminzing source and also a reducer for titanizing, an activator of NH4Cl and albumen （egg white） as cohesive agent. The Ti-Al coating was fabricated on the surface of electro-deposited nickel layer on copper matrix followed by the slurry pack cementation process. The effects of slurry pack cementation temperature on the microstructures and wear resistance of Ti-Al coating were studied. The results show that the microstructure of the coating changed from NiAl＋Ni3（Ti,Al） to NiAl ＋Ni3（Ti,Al）＋Ni4Ti3 to Ni4Ti3＋NiAl, and to NiAl＋Ni3（Ti,Al）＋NiTi with slurry pack cementation temperature ranging from 800 ℃ to 950 ℃ in 12 h. The friction coefficient of Ti-Al coating decreased and the hardness increased with increasing the slurry pack cementation temperature. The minimum friction coefficient was 1/3 and the minimum hardness was 5 times larger than that of pure copper.

Study on the rheology of coal-oil slurries during heating at high pressure

Using the self-developed viscosity measuring device, the viscosity variations of coal-oil slurries with temperature increasing during coal-oil co-processing were studied. The results show that the viscosity of coal-oil slurries prepared by different kinds of oil varies differently during heating. The viscosity of the coal-oil slurry prepared by the catalytic cracking slurry （FCC） generally decreases during heating. However, the viscosity of the coal-oil slurry prepared by the high-temperature coal tar （CT） will peak at 338 ℃ during heating. The differences in viscosity variations of coal-oil slurries are analyzed. In addition to the temperature, the properties of the solvents and coal are the main influencing factors. Because the used coal contains a large number of polar functional groups, the swelling behavior of the coal in polar solvent （CT） is stronger than that in non-polar solvent （FCC）. The swelling effect of the coal can result in the appearance of the viscosity peak. Therefore, before 100 ~C, the solvent molecules entering into the coal pores is the main influencing factor of coal-oil slurries viscosity variations. After 100 ℃, the increasing of particle size of coal particles is the main influencing factor of coal-oil slurries viscosity variations.

Facile Adjusting for Cells of Lightweight Isocyanate-based Polyimide Foam and Operable Combination between Different Distinctive Acoustic Foams for Higher Performance

New ambient sound absorption material,lightweight isocyanate-based polyimide foam(IBPIF),was fabricated by operable combination between different distinctive acoustic IBPIF.Cellular structure of IBPIF was facilely and obviously adjusted by increased slurry temperature corresponding to change in distinctive acoustic properties.Moreover,density of all IBPIF kept at only 12-17 kg/m3.With increasing slurry temperature from 0℃to 40℃,cell size and window opening rate gradually increased from 553μm to 791μm and from 6.85%to 58.46%,respectively.In this study,IBPIF generated by slurries at 0℃(marked as PIF-2)and 40℃(marked as PIF-6)showed best and distinctive acoustic behavior in 315-800 Hz and 800-6300 Hz regions,respectively.After acoustic behavior study of combined IBPIF prepared by stitching combination between two distinctive acoustic IBPIFs,results showed that only when PIF-6 sheet used as sound receiving surface even though with thickness of only 10 mm could the combined IBPIF possess the best acoustic level in 800-6300 Hz region as PIF-6.Furtherly,acoustic behavior in 315-800 Hz region could be significantly enhanced by increasing thickness of PIF-2 and could reach or close to the best acoustic level.