The application of refractory coating is critical in the foundry production process. In order to prevent sand sticking and other defects, improve the surface quality of castings, and reduce the rejection rate of castings, a layer of fire-resistant coating applied to the surface of the mold and core is an important process measure. Casting coatings have become increasingly popular in recent years, particularly in the production of cast steel and iron castings. Foundry coatings are produced by a large number of companies in developed countries. At the moment, the majority of the Foundry coatings research being conducted in China is focused on coatings for cast steel and iron castings, with less attention being paid to coatings for large aluminum castings.A large aluminum casting's surface roughness, sand sticking, and sand inclusion are all caused by the casting's complex structure, wide wall thickness difference between the walls, large weight, and large surface area. Some industries require high surface quality and dimensional accuracy from their castings, and some industries do not https://www.diecasting-mould.com/zinc-die-casting zinc alloy die casting. As a result, it is extremely important to investigate a coating for aluminum alloy castings that has high surface strength, low gas evolution, and is capable of preventing casting defects from forming.There is a layer of dark oxide film on the surface of the die-casting aluminum parts, and some oil stains, such as release agent, are adhered to the surface, as well as some local burrs in the aluminum. As a result, surface treatment is required for these aluminum castings. We have carried out numerous experiments on the surface chemical polishing of these aluminum parts using a chemical method, determined the appropriate formula and process conditions, and put them into mass production to demonstrate their effectiveness. The chemical polishing process is capable of meeting the needs of the manufacturing industry.The most important technological process in surface treatment is oil removal followed by water washing, alkali corrosion followed by water washing, polishing followed by water washing, ash removal followed by water washing, oxidation followed by water washing, drying followed by calendering, and finally the finished product.2. The conditions of the formulation and processingIn the surface treatment of aluminum alloy castings, all of the raw materials used are commercially available products. All solutions are prepared with tap water, and between processes, cold tap water is used to wash the equipment and clean the surfaces between processes.2.1 cleaning and degreasingQuancheng brand slurry detergent produced by Jinan toothpaste factory, which is mixed with 10% water solution flow and treated at room temperature for 10-30 minutes or heated to 80% for 10-30 minutes, is used as the degreasing  https://www.diecasting-mould.com die casting mold agent. The control of temperature and time is primarily dependent on the presence of an oil stain on the surface of the aluminum alloy casting. As an example, consider the principle of clean treatment.2.2 Alkali corrosion is discussed.The purpose of alkali corrosion is to remove the oxide film that has formed on the surface of aluminum castings, on the one hand, and to remove any remaining oil that has not been removed during the degreasing procedure, on the other. The solution used for alkali corrosion is 10% na0h, the temperature of the water solution flow is 40-80°C, and the time required is 0.5-3 minutes. In order to avoid overcorrosion, the time should not be too long.polishing (2.3)After alkali etching, the workpiece can be cleaned with water before being immersed in the polishing solution for polishing and finishing. There are four types of inorganic acids in the polishing solution, which are: phosphoric acid, sulfuric acid, nitric acid, and boric acid, among others. The polishing process takes 1-4 minutes. After polishing, the surface of the workpiece is smooth and free of burrs, but there is a layer of black floating ash on top of it. In part due to the fact that the silicon contained in ZL105 casting aluminum is insoluble in the polishing solution, it precipitates in the workpiece after it has been polished. Because surface ash cannot be removed by simply washing it away with water, it must be treated specifically in the ash removal liquid in order to remove the surface ash.2.4 Removal of ashIt is an acidic solution that contains fluoride, which is used in deashing. When it is treated at room temperature, there is no need to heat it up before use. The reaction time is only one and a half seconds. It should be noted that, as long as the floating ash is removed, uniform gray surface tiles can be obtained after the ash has been removed from the surface. The treatment of the surface with oxidation can be done in the oxidation https://www.diecasting-mould.com/ custom die casting solution if the treatment of the surface is required. The water can be thrown dry as soon as possible after washing, and the water can be dried naturally in the dry bath if oxidation treatment is not required. It goes without saying that drying equipment is not required. Upon drying, the surface of the workpiece should be gray in color and uniform in appearance.2.5 The process of oxidationUsing chemical oxidation, the goal is to form a dense oxide film on the surface of the casting in order to increase the corrosion resistance of aluminum casting. There are 47g of sodium carbonate in 1L of solution, 14g of sodium chloride in 1L of solution, and 0.06g of sodium silicate in 1L of solution. The oxidation temperature ranges between 90 and 100 degrees Celsius, with an oxidation time of 10-15 minutes. The surface color of the workpiece is essentially unchanged or only slightly altered after it has been subjected to oxidation treatment.2.6 Following treatmentMechanical calendering can be used to achieve the bright silver gray surface that has been achieved through chemical polishing and oxidation.