Research of surface wettability of plating on the ceramic shell
The wettability of coating surface has important significance in the spreading situation of piece of sticky piece, and the welding state of Au-Sn solder. Wettability of solids is expressed with wetting contact angle. In this paper, by studying the wetting angles of the water droplets on the surface of the different ceramic shell, assess the wettability on the surface of the ceramic shell, and the ways to improve the wettability is proposed through experiments. The results of the experiment show that the presence of organic matter reduces the wettability of the coating surface, so the wetting angles of the coating surface are large in the analysis process. After the plasma cleaning, organics were washed subsequently, and the wettability of the surface coating increased, so the wetting angles are decreased.
The stabilisation of aqueous suspensions of coal particles
Abstract Dilute suspensions of coal particles having average diameters of 1 μm have been prepared from coals from the Shanxi Province, the People's Republic of China, and from the UK. The suspensions were stable only in the presence of surfactant repellants. Measurements of zeta potentials showed suspensions stabilised by non-ionic and ionic surfactants to behave very differently. The effects of the concentrations of repellant and of electrolyte, of the rank and maceral group composition of the coal and of the pH of the medium are contrasted for suspensions stabilised by a polyether, by CTAB and by a lignosulphonic acid. The non-ionic, polyether repellant which formed monolayers on the coal surface, each molecule being bound at more than one site, probably to oxygen groups, readily stabilised the colloidal system by pushing the zeta shear plane away from the coal surface. Larger concentrations of the ionic repellants were needed to confer stability, which they did by the formation of complex charged species on the coal surface.
Formation and Strength of Magnesia Whiskers
The formation of single-crystal magnesia whiskers during the compressive deformation of single crystals at room temperatures is described. These whiskers can have strengths of the order of millions of pounds per square inch. They are formed during fracture as a result of the discontinuous propagation of cracks which are mechanically relieving internal stresses resulting from plastic flow