Investigation On Materials Selection For Waterborne Zinc-Aluminum-based Metal Powder Coatings

At present the metal protection industry receives the stern pressure stemming from environmental protection and energy conservation and so on, ultimately the coating industry is developing to environmental protection day by day. The river character metal-based fine powder coating,using the laminated metal fine powder, taking the inorganic salt or the organic solvent as the cementing agent, joins other surface active agent and so on for pulp, then is spreaded on the metal, forming the metal-based coating after the agglutination. The river character metal coating has gradually become the hot spot studies now, for its outstanding corrosion resistance, the thermal stability, without the hydrogen embrittlement, overcoatability and the construction convenience and so on.The paper on the foundation of summarizing the predecessor research work's discovered that there are some blind spot and unfairness in the component choice and in the shape level principle of the river character metal-based coating's research and application, which has affected this kind of coating technology development and the application.In view of this, this paper started with the principle of selection, analyzed the performance and the role of the materials in each group as well as its impact on coating performance, researched the method and principles of the selection of the material selection, and determined a more reasonable and scientific method and principle of the material selection. It was found that, Smaller surface tension non-polar organic wetting agent on the wettability of the metal powder is better, and the wetting agent must be met,any immiscible with water; thermal decomposition of the coating after curing of the coating without residual; dispersant solution can improve the coating of organic and inorganic pigment dispersion of solid particles to prevent the settlement of solid particles and condensation to form a stable suspension, the experimental F selected dispersant has good dispersion; for thickener selection, lower prices and better quality of the coated cellulose thickener thickening fluid well, and coated solution without side effects.Papers focus on the selection of the binder and study the Molybdate, phosphate, and borate and silicate binder coating formation. The study found that the main force between the substrate binding and a binder coating consists of molybdate, phosphate and borate are:Interface static gravity, the van der Waals force between Coating and matrix elements, Mechanical force. The bond strength is low.There is also chemical bonding except for the three forces above, and its bond strength is bigger than the other three.Through the analysis of the inorganic binder types mentioned above, we find that the Composite binder which is Mixed by a few kinds of inorganic binders has a good ability of Compatible and co-existence.the new coating has a solid three-dimensional structure coating, Its binding forces include Van der Waals force, mechanical force, electrostatic force and chemical bonding. Its overall performance is superior to several other single binder coating.The property of this metal zinc aluminum base river character fine powder coating which is obtained through the experiment is very fine, for its physical property and resisting corrosion:The coating surface is smooth, even, assuming the brilliant white, the strong coating binding force, the fine anticorrosion performance.We observed the micromorphology of the coating bonding state with the matrix,Spatial location and analyzed the chemical components of the coating statistically and effect of each component to the coating,by using moden measuring methods such as Stereo microscope,SEM,energy spectrum analyzer. The results indicated that, the aluminium flake placed on top of one another basically, while the Spherical zinc placed among the spaces of the aluminium flakes unevenly and the metal powder.Baseding on the above fingdings raised the mechanism of shaping and corrosion of Waterborne Zinc-Aluminum-based Metal Powder Coatings:Waterborne aluminium-based metallic micro-powder coating have no electric crystallization in the forming processof coatings,and no high-temperature metallurgy react, it's mechanism of shaping different from the tradition crystallization way,So technology belongs to one kind of among the technology of obtaning the dense plural alloy-layer by way of there is no crystallizationing. Mechanism of corrosion resistance at both barriers and protective sacrificial anode. The technology is expected to become a new type protective coating that having environmentally friendly.