Coating powders types

Transition-metal -phthalocyanines as catalysts in acid medium. To prevent carbonate formation by the carbon dioxide in the air or that produced by oxidation of carbonaceous fuels, an acid electrolyte is necessary hence it is important to find electrocatalysts for an acid medium. Independently of Jasinski, we were soon able to show 3>4> that under certain conditions the reduction of oxygen in dilute sulfuric acid proceeded better with phthalocyanines on suitable substrates than with platinum metal. The purified phthalocyanines were dissolved in concentrated sulfuric acid and precipitated on to the carbon substrate by addition of water. This coated powder was made into porous electrodes bound with polyethylene and having a geometrical surface of 5 cm2 (cf. Section 2.2.2.1.). The results obtained with compact electrodes of this type are shown in Fig. 6. 

This gains its name from its appearance as a charcoal ball. This is manufactured by coating a black powder type composition many times on an ordinary and rather small shell. During the coating process pieces of hemp are wound around the sphere for reinforcement. This is quite labour intensive, but the effect is very pretty(Fig.8). The fuse of this shell is apt to misfire due to the absorption of moisture during coating, and some device is necessary to avoid this. 

Hercules Powder Co., Wilmington, Del., A Survey of the Paint, Varnish and Lacquer Industry, 1945. Production of surface coatings by type and materials used in manufacture of surface coatings. 

The CVD method involves a chemical reaction in a vapor phase which results in deposition of a solid on a heated surface. Various PVD processes such as ion plating, sputtering, molecular beam, evaporation, and epitaxy might be also included in CVD processes [112]. The various CVD methods are powerful processes used for the fabrications of a wide variety of thin-film materials including solar cell materials and semiconductor materials for electronic applications, as well as the manufacture of coatings, powders, fibers, and monolithic components. There are two types of CVD reactors, the differential reactor and the starved reactor, according to the value of the flow rate (F,) defined as... 

Similar processes took place in the case of porous YSZ coating (powder and polymer ratio of 5 1). The only difference is the amount of nanocrystalline YSZ derived from the polymer was not sufficient to fill all space in the initial YSZ framework resulting a porous ceramic material with well-developed connection between particles (Figure 3-3c). This type of material cannot be used as an oxygen separation membrane because it has open porosity, but it can be useful as the YSZ skeleton for the electrodes, as it has high effective surface area for exchange with the gaseous phase. 

Table 3.4. Production of thermosetting coating powders in 1995 classified according to binder types...

Aluminum pigments, polymer coated (PCA-type) PVC, powder coating, thermoplastic resins, thermosetting resins Improved chemical resistance and outdoor durabihty better resin compatibility... 

The vast majority of thermosetting coating powders are prepared by melt muting. Some thermoplastic powders are also produced by this method but most are manufactured by the dry-blend process as shown in Figure 1. Production methods based on spray drying from solution (86) and precipitation from solution (87) have been evaluated but never achieved commercial success because of difficulties in solvent and/or water removal from the powders. Many types of coating powders are still manufactured in small batches, eg, 50-1500 kg, due to differences in color or chemistry, where chemical processes are not economical. 

Nickel hydroxide active material is provided by reacting nickel sulfate solution and an alkaline solution. A part of nickel of nickel hydroxide is substituted for Zn and Co for the improvement of the battery performance. The theory capacity of nickel hydroxide is 289 mAh/g by supposing one electron reaction. The utilization of nickel hydroxide of a sintered-type electrode is approximately 100 %, but that of a pasted-type electrode without a conductive additive is around 65 %. The improvement of the utilization is enabled by forming CoOOH conductive networks between nickel hydroxide particles. The cobalt compound (Co, CoO, Co(OH>2) is filled into the formed nickel substrate with nickel hydroxide as an additive. The Co compounds form a conductive network as CoOOH by charging. To improve the conductivity of the cobalt conductive layer, Co(OH)2 layer coating to the surface of nickel hydroxide particles and the oxidation treatment in an alkaline solution of this coated powder are suggested. 

---